WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.

January 2010 Archives

Two snow systems help Chicago greet February

|
Winter 2009-10 opened with a snowy flourish with more than 28 inches falling in December and early January, but since then, only meager snow amounts have been recorded as the area's snow cover has dwindled to an inch or less.

Despite the recent lack of snowfall here, major snowstorms have buried the South and current national snow cover stands at 70 percent, the highest value recorded since observations began back in September 2003.

While no major snowstorms appear in the offing for Chicago, two systems have the potential to deliver accumulating snow. The first on Monday night and Tuesday should be a minor event bringing an inch or two with heavier totals expected north and west of the city. The second one, slated to arrive Friday night, could start out as rain but change to accumulating snow as colder air returns on Saturday.

Extreme cold lacking

With two-thirds of meteorological winter behind us, the city has officially recorded only one day with below zero readings: a low of minus one on Jan. 3. By this time last winter the city had recorded nine subzero days, including a low of 18 below zero on Jan. 16.
FEATURE02012010.jpg

Is this our cloudiest winter?

| | Comments (3)
Dear Tom,
Is it my imagination or has this been the grayest, cloudiest winter ever?

-- Erin O'Connor


Dear Erin,
Your impressions are right on. It has been a very cloudy winter to date. However, as dreary as it's been, it has been worse.
According to Chicago climatologist Frank Wachowski, since Dec. 1, this winter has logged 27 totally sunless days. Since the inception of sunshine records in 1894, only three winters have had more cloudy days through the end of January: 1997-98 with 33, 1968-69 with 30 and 1940-41 with 28.
Wachowski noted that this winter has featured extended sunless periods; an eight-day string from Dec. 17-24 and more recently a seven-day stretch from Jan. 20-26.
 

Few lake flurries here while South battered by snow and ice

|
Cold weather continues to grip the Chicago area this weekend, but aside from a dusting of lake-effect snow in the city and northern suburbs Friday night and early Saturday, dry weather was the rule. In sharp contrast, the South is reeling from another major winter storm that left a three-day, 1500-mile-long legacy of snow and ice from Kansas and Oklahoma all the way to the Atlantic coastal areas of Virginia and the Carolinas. More than a foot of snow fell in many areas including 13 inches at Lynchburg and Forest, both in Virginia, and 13 inches at Mills River, N.C. South of the snow, a heavy glaze caused extensive damage to trees and power lines and created an icy havoc on roads. This is the second major storm of the winter to blast these areas, the first occurring in the days leading up to Christmas.

Snowy primary day shaping up
The next weather system is likely to spread its wintry precipitation farther north, bringing some snow to the Chicago area Monday evening and continuing into Tuesday, the day of the Illinois primary. While a major snowfall does not appear to be in the offing, it does appear that at least a couple of inches of snow could accumulate here by Tuesday afternoon.
FEATURE01312010.jpg

Can February have two full moons?

|
Dear Tom,
Last December we had two full moons, the second one being on New Year's Eve. When was the last time February had two full moons? Wouldn't it have to be in a leap year?
--Pamela Eiten

Dear Pamela,
The answer is never. By nature of the 29.5306-day lunar cycle, February, with 28 or 29 days, can never host two full moons. In fact, it is the only month of the year that can be without a full moon. When this occurs, both January and March will sport double-full moons. That last two times this happened were in 1961 and 1999, and future occurrences will be in 2018, 2037, 2067 and 2094. Astronomer Dan Joyce of Triton College's Cernan Space Center tells us that in general, two full moons in one month occur about every 32 months; the next time being in August 2012.

Weather word of the day

|
20100129weatherword.jpg

A whole season's snow in one storm- Virginia Beach, Va.

|

Thanks to Tony Russo of Virginia Beach, Virginia for passing along these photos of the snowstorm that is hammering the area. Tony reports heavy snow mixed with sleet still occurring Saturday afternoon with 7.5 inches on the ground- more than that area typically gets in an entire winter.

Modified IMG_0224 [640x480].jpg

Modified IMG_0228 [640x480].jpg

Photos by Tony Russo

January moves into its final two days this weekend, closing as it opened--COLD! The bitterly cold readings are easing slowly with time. Daytime high temperatures warmed from 13 to 21 degrees Thursday to Friday, and even higher readings are on tap Saturday and Sunday. But while the mid to upper 20s predicted both days continue the recent temperature upswing, they will fall nearly 20 degrees shy of last weekend's unseasonable mid-40s.

Flurries continue fluttering earthward as Saturday gets underway. A modest lake-effect snow event is in place--but the depth of the day's cloud layer is shallow compared to those which have produced more prolific and heavier snows in the past. Barring the unexpected, accumulations appear likely to remain limited, both in depth and areal coverage. Winds are to become even less supportive of lake snow development as the day proceeds, allowing precipitation to taper to sporadic flurries this afternoon and evening.
   
Longer days, strengthening sunlight hits milder temperatures ahead
 
It takes a while to transition from one season's temperature regime to the next.  But the astronomical groundwork for the move to spring is falling into place.  Days are lengthening and the strength of sunlight is on the rise. Chicagoans can look forward to an additional hour and 15 minutes of daylight in the next 30 days--and to two hours and 45 additional minutes of sun two months from today. Though it may seem an eternity to the winter weary here, Chicago weather records reveal the average final 32-degree temperature occurs on or about April 19th at Midway Airport and April 26 at O'Hare Airport.  And the majority of daytime highs reach or exceed 70 degrees in Chicago 50 percent or more of the time beyond May 23.
 
Winter woes from Mid-Atlantic westward into the Midwest
 
While chilly here, Chicago's weather problems pale in comparison to those of recent days along a 2,000-mile swath extending from New Mexico and Oklahoma east to the Carolinas and Virginia. There, heavy wind-driven snow accumulated to a depth of as much as 14" in spots. Snowfall Friday piled up quickly in North Carolina, reaching 9" at Asheville by nightfall. Storm tallies since Thursday include 14" at Gruver, Texas; 10" Enid, Okla.; 11" Ingalls, Kan., and 8" Henderson, Tenn.
 
Snow could fly Monday night and Election Day (Tuesday)
 
 An eastbound disturbance off the Pacific may be the next to deliver snow to the Chicago area. The period in question is Monday night into Primary Day (Tuesday). Temperature changes at high altitudes offer forecasters clues on the potential extent/intensity of snowfall a weather system may produce. Projections from computer models in the Monday through Tuesday time frame is hinting at fairly impressive warming at high levels of the atmosphere (around 40,000 feet). It's a development which suggests air within the system is likely to be rising vigorously enough to support sticking snow. The system will be monitored in coming days as it proceeds toward the Midwest.
FEATURE01302010.jpg

Is snow sticking ... around?

| | Comments (1)
Dear Tom,
I recall growing up in the Chicago area in the 1960s and '70s that the snow hung around a lot longer, sort of like this winter. Am I correct?
--Jim Gross

Dear Jim,
Time will tell, but so far this winter is off to a snowy start. Days of snow cover are a good indicator for gauging the severity of a winter. Many days of snow cover not only equate to substantial snowfall, but also indicate little thawing and overall lower winter temperatures. According to Chicago climatologist Frank Wachowski, the city's average number of days per winter with 1 inch or more of snow on the ground is 43. Chicago's snowiest winter -- 1978-79 with 89.7 inches of snow -- also holds the record for the most days of snow cover with 100. In contrast, the winter with the least days of snow cover was 1948-49 with eight. So far this winter we have logged 41 days with a lot of winter still ahead.

Snow piling up in the North Carolina mountains

|

WGN-TV/Chicago Tribune Meteorologist Richard Koeneman reports that snowfall in the mountains near Asheville has reached to about 6 inches and is still falling at a heavy rate. Snow totals are expected to top 12 inches before the storm ends. 

ashville snow.jpg

Photo by Richard Koeneman

Perigee moon in all its splendor

|

Thanks to Dolores Hager of Hanover Park for sending us this great host of tonight's full moon. This full moon is to appear the biggest and brightest of the year because the moon is currently at perigee- its closest point to the Earth in its elliptical orbit.   

Moon [640x480].JPG

Photo by Dolores Hager

A wintry scene in Nashville

|

Not too many sunbathers and swimmers in the Nashville area today as a winter storm is lacing the area with heavy snow. This picture was sent to us by  former Chicagoan Lisa Nisevich. The photo was taken by her husband who was attending a conference in Nashville.

Nashville Snow [640x480].jpg

Snowstorm in the mountains of North Carolina near Asheville

|

Our WGN Weather Center colleague Richard Koeneman just sent in these pictures of the beginning stages of what promises to be a another major snowstorm in that area. By the time the storm ends later this weekend, snowfall totals are expected to be in the 10-14 inch range. That area was also hit by a 15-inch snowstorm back in December just before Christmas.

20100129ashevillesnow02.jpg


20100129ashevillesnow01.jpg

Photos by Richard Koeneman

Tim's Weather World: Winter Storm Slams South

| | Comments (1)

It could always be worse....

At least seventeen southern states have some form of advisory/watch/warning for a major winter storm that is producing freezing rain, sleet and snow from New Mexico to North Carolina

Click on the picture of ice below for more details about this storm.

 

Watches.jpgParts of Oklahoma had an inch and a half of ice that snapped tree limbs that fell into power lines and left thousands of people without power.  More than a foot of snow fell in the Texas Panhandle yesterday. Raleigh, North Carolina is bracing for as much as 4 to 8 inches of snow.  Some of the areas impacted by this storm have little if any snow removal equipment.  Having worked in New Bern, North Carolina, I can attest to how easily a half inch of snow can cripple communities there.

 

Here is me in my North Carolina days circa early 1990's-

 

menc.jpgWe will get cloud cover from the storm today and the circulation around the southern system will bring us north/northeast winds.  Those winds might produce some light lake effect snow tonight and early tomorrow. 

A modest lake-effect snow set-up appears to be trying to come together for Chicago and the lakeside counties of southeast Wisconsin, northeast Illinois and northwest Indiana in the next two days. Friday is to dawn with sunshine on display in the city and over much of the metro area---sun which is to begin mixing with clouds in lakeside areas as the day proceeds. Flurries may follow later in the day and from time to time over an approximately 28 hour period extending into Saturday night.

Lake effect snow flurries have been fluttering to earth across the western Michigan snow belt southward into north-central Indiana since Thursday. A change in wind direction, dictated in part by the influence of a powerful storm system passing well to Chicago's south and lambasting the Plains with ice and snow, may encourage those flurries to begin building westward in the hours to come. Frigid northwest winds driving snowflake development in Indiana and Michigan are predicted to back slowly Friday---first to the north and then to the northeast. The effect will be for lake clouds blowing Friday morning into sections of the Indiana and Michigan snow belt to gradually shift west---ultimately moving them closer to Chicago. Predicted wind profiles suggest the first lake-effect flurries could reach the western shore of Lake Michigan---including the city---as early as mid afternoon to early evening.

A wind speed increase is to follow just above the ground Friday night into Saturday. It's at this point flurries may build at times into some heavier snow showers. That would happen as faster- moving air coming off the lake converges with winds slowed by the frictional drag encouraged as they contact land. A pileup of air results when faster winds converge with slower-moving air and upward motion soon follows. That cools the air to condensation increasing cloud development, at the same time allowing snowfall intensity to increase. As with all lake-effect snow situations, it's unlikely to snow continuously. Snow is most likely to fall in distinct spells. But, some accumulation may occur if the situation unfolds as predicted.
   
 
75 percent of Chicago's winters have produced a colder temperature by now
 
Weather records reveal 107 of the 139 winters on record here since 1871 have produced a colder temperatures by this date than the 1-below which stands as THIS season's coldest.  Thursday's high of 17-degrees occurred at midnight---a peak reading of 13-degrees occurred during daylight hours. It was the coldest air to engulf the city in the 26 days since Jan. 2. Winds chills---other than the readings taken at midnight---failed to break above 0-degrees---falling as low as 11-below around 7 a.m.
 
Oklahomans jarred by temp plunge; spring warmth replaced by ice, wind and snow
 
A nightmarish scene unfolded Thursday across sections of the southern Plains. The region had basked in spring like 60s only the day before. But the same arctic air mass behind Chicago's frigid temperature regime dove into Oklahoma and north Texas, sending temperatures plunging as sleet, freezing rain and wind-driven snow hit the area. Temperatures Thursday afternoon in Oklahoma City dipped into the 20s amid howling northeast winds amid heavy sleet and freezing rain. Readings 24 hours earlier had topped out at 65-degrees.

The inch and a half of ice which built-up on many outdoor surfaces in Oklahoma brought trees and power lines down across the region inducing widespread power outages. Among the areas hardest was Jackson County, southwest of Oklahoma City, were at least 200 power poles snapped.

It was heavy snow which was big news in the Texas Panhandle, northern Oklahoma and southern Kansas. Top accumulations had reached 13 inches by nightfall Thursday.
 
 
 


 

Area shivers through lowest temperatures in 26 days

|
FEATUREGRAPHIC012910.jpg

ELECTIONDAYSNOW012910.jpg

Rapidly moving clouds

|
Dear Tom,
I looked at the sky this morning and the clouds were moving fast. Does that mean there will be a storm?

Sam Ganzel (age 8)

Dear Sam,
Rapidly moving clouds do not necessarily mean a storm is coming. Clouds appear to be racing across the sky because they are close to you, in other words, they are low clouds and not very far above the ground. Here is an example to illustrate the point. You are able to see very low clouds -- clouds generally within 500 feet of the ground -- only when they are within a mile or two of you. If those clouds, at 500 feet, are moving at 25 mph, they will be within your field of vision for about 10 minutes, at most. But high, wispy cirrus clouds, often above 30,000 feet and moving at 60 mph, can be seen from 50 miles away. Despite their speed, it will take them at least 1 1/2 hours to move through your field of vision.

Are you Cheimaphobic?

|
WWCheimaphobia012910.jpg

Arctic blast keeps southern storm away but brings sub-0 chills

|
Arctic air tightens its grip across the Midwest Thursday. A highly-reflective fresh cover of snow all but assures sub-zero wind chills will dominate the day despite the presence of sunshine.

Sunlight typically heats air indirectly, warming the ground onto which it falls first. A fresh accumulation of snow defeats that process by reflecting solar energy back to space. Wednesday afternoon and evening snowfalls included 1 inch in Plainfield and Yorkville as well as at Schererville and Highland in northern Indiana. Other Wednesday snow totals included 0.9 inches at O'Hare, 0.8 at Peotone. 0.6 at Oak Brook and 1.2 inches in Portage Ind.

Computer trajectory forecasts, which track the movement of air indicate Thursday's chill originated in the Dakotas 24 hours ago. There, temperatures flirted with zero Wednesday. With news snow in place, it's likely the air mass will retain its arctic character as it arrives in Chicago allowing temperatures here to rise no higher than the teens and to drop sub-zero away from the lake Thursday night. Gusty northwest winds of 10-22 mph Thursday assure wind chills will remain between 0 and 12 below. 

Arctic air deflecting major snow and ice storm south of Chicago

The blast of arctic air is having a major impact on the track of the latest Pacific storm to come ashore in the United States. The system emerges from the southern Rockies into the southern Plains Thursday and proceeds east assuring its formidable snows and accumulations of ice remain well south of Chicago. In Oklahoma, where residents basked in springlike 60s Wednesday, plunging temperatures and howling east winds are to deliver ice and snow Thursday. The storm's impact may not completely bypass Chicago. Its winds are to interact with a Canadian high pressure producing a north-to-northeast flow which begins sweeping into Chicago off Lake Michigan late Friday through Saturday. Over that 28 hour period the potential for lake-effect snow showers and flurries rises here. Some accumulation is not out of the question.
 
El Nino taking a big bite out of seasonal snow tallies here
 
Each El Nino has its own character.  The differences from one such period to the next can be formidable. But, as a general proposition, El Ninos are known to produce storms which crash into the West Coast---last week's storm parade serving as a spectacular example---then tracking through the southern states. It's a development which boosts cold season snowfall in the Plains but often slashes snowfall in the Midwest. Data from these regions on snowfall to date indicates how closely this season's snowfall is tracking with many past El Ninos. Snowfall is substantially lower in Chicago and the area which surrounds it this year versus last. O'Hare's snowfall (prior to Wednesday's system) is more than 13 inches lower than a year. Other declines include Rockford: down 23.7 inches from a year ago, Milwaukee off 27.5-inches and South Bend with a seasonal tally down 23.2 inches.
 
 


 

Lake snows shift from Indiana to Chicago late Friday

|
FEATUREGRAPHIC012810.jpg


PREDICTEDOWS012810.jpg


TEMPFORECAST01281001.jpg

Chicago's record cold in January 1985

|
Dear Tom,
My mother always tells me how much it was snowing just before I was born on Jan. 25, 1985, but she never wrote down any details. Just how bad was it?

Kathleen McCoy, Naperville

Dear Kathleen,
Though there was snow on the days leading up to your birthday, the real story in Chicago that month was the record cold. Over the three-day period from Jan. 16 to Jan. 18 the city received about 5 inches of snow. Another 1.2 inches fell Jan. 24 and an additional inch on your birthday, bringing the city's snowpack to 8 inches. But, five days before you were born, on the morning of Jan. 20, the official thermometer plunged to minus 27 degrees, the city's lowest reading ever, and coupled with strong winds, wind chills hovered near 80 below zero. Readings did not break freezing the rest of the month, which closed with a low of minus 12 on Jan. 31.

Definition of "Frazil"

|
Frazil012810.jpg

Tim's Weather World: Big Snow of '67

| | Comments (5)

This is the 43rd anniversary of the single biggest snowfall on record for Chicago.  The blizzard began around 5 AM on the morning of January 26th, 1967 and continued until about 10 AM the next morning.  Only 4" was forecast but when it was all said and done, almost 2 feet of snow fell with drifts up to nearly 20 feet high.

 

67 blizzard.JPGI remember barely being able to see my neighbor's house across the street.  In Schaumburg they came down our street with a front loader to remove drifts as tall as two story houses.  Nearly 50,000 cars and 800 buses were just abandoned right in the middle of the street.

 

For more pictures and an article about the storm, check out

http://www.chicagotribune.com/news/politics/chi-chicagodays-1967blizzard-story,0,1032940.story

Check out http://www.youtube.com/results?search_query=67+blizzard&search_type=&aq=f for a look back at the storm.

www.facebook.com/TimMcGillWeatherGuy

 

http://twitter.com/WGNWeatherGuy

Not since 1999 has there been a longer spell of cloudy January weather in Chicago. Clouds have blocked the sun here the past 7 days, noteworthy even in a month which typically ranks among the year's three cloudiest. All clouds of recent weeks have impacted temperatures, slashing daytime highs while buoying overnight lows. January's average temperature, until several weeks ago, well below normal, has rebounded---a trend which may slow or even reverse in coming days as the latest cold surge tightens its grip on the area.  For the moment, the month is in surplus territory.

It comes as little surprise to most Chicagoans that January's sunshine tally has been truly dismal. For record-keeping purposes, sunshine is measured in minutes--and January 2010 has managed only 4,438 minutes compared to a possible 14,778. That's only 30 percent of the the month's possible sunshine and far short of the 43 percent which normally occurs.

Tuesday's 24-degree O'Hare high was the coldest in 16 days---and 20 or more degrees below this past weekend's mid 40s. In the nights ahead, inland readings will drop to single digits Wednesday night and sub-zero Thursday night. 

Despite prospects of a new outbreak of arctic air the next few days, the 2009-10 cold season has widened its temperature lead over a year ago. Readings since Dec. 1 have averaged more than 5-degrees milder than the same period a year ago. A winter-to-winter comparison of the coldest temperatures to date underscores the warming which has taken place this season. The coldest low temperature to date has been minus 1-degree on Jan. 3 versus the  bone-chilling minus 18-degree which had been registered by this time a year ago.
   
Plains & South brace for a wintry assault
 
The latest storm to sweep from the Pacific onto the U.S. mainland is on track to hit areas of the central and southern Plains and northern Gulf Coast region hard with ice and heavy, wind-driven snows. In Oklahoma City, where on Christmas Eve (Dec. 24)---a little over a month ago---a blizzard deposited more than 13 inches of snow amid 60+ mph  gusts---the most on record there in a single storm. The snow/wind combo was devastating for those who hoped to travel,  blocking thoroughfares through the region. Winter storm watches have been hoisted in advance of the new storm and forecasters warn of accumulations which could top 12 inches in areas hardest hit.

Chicago may not entirely escape the system's reach later this week---particularly its winds. While the storm is predicted to pass well to Chicago's south, the north to northeast winds it may help establish here could be enough to draw winds off the lake, activating the lake-effect "snow machine" Thursday through Friday---first in the Indiana and Michigan snow belt on Thursday.  Snows may then shift west Friday into Saturday bringing flurries or snow showers to Lake Michigan's Illinois, Indiana and southeast Wisconsin shorelines.
 
Warmth will come sooner than you think!
 
Wednesday marks the first time since last Halloween (Oct. 31) that the sun will set at 5 p.m., a by-product of slowly lengthening days. But there are other signs winter is maturing and that milder days edge closer. Days are lengthening and "normal" temperatures are on the rise---having bottomed out last week (Friday, Jan 22). If coming months behave in line with long-term averages, a high temperature of 70-degrees may only be around 58 days away and the Chicago area's first 80 is likely to hit in 85 days on April 22.
 
 


 

FEATUREGRAPHIC012710.jpg

SNOWOUTLOOK012710NEW.jpg

Dear Tom,
All the recent heavy lake-effect snow in northern Indiana reminded me of a huge storm that paralyzed Michigan City, Ind., in the 1950s or '60s. Can you provide details?

--Larry Robinson

Dear Larry,
On Feb. 15 and 16, 1958, one of the biggest Lake Michigan snow events on record buried Michigan City with more than 40 inches of snow during a period of about 36 hours. The strong winds blowing arctic air down the full length of the lake piled the snow into huge drifts, some as high as 15 feet. The snow was so deep that bulldozers were needed to help the town dig out. The area of the exceptionally heavy snow was small and neighboring communities thought the snowstorm was a hoax because skies as close as Gary were clear. Nearby LaPorte received 5 feet of snow in February 1958, much of it falling during that storm.

Definition of "Slush"

|
Slush_012710.jpg

Frozen yard

|
Sharon Colwell sent us this picture of her frozen yard; she tells us:

In this wintry weather, my husband was unable to remove the Christmas decoration that was frozen to the ground in thick ice.   He was only able to remove the figures from the nativity scene.  So he left a sign on the display.  Thought you'd enjoy it!
012610snowbox.jpg
Photo courtesy of Sharon Colwell


Fox on Crystal Lake carrying a muskrat

|
Check this out!  Grant Bevill writes us: 
 
"My wife Judith and 8 year old daughter Kathryn took this picture of a fox with a recently captured muskrat in his mouth. It was a real life nature program. The muskrat had made a home in our sump discharge so the fox was more than welcome."
 
It's not everyday we receive a shot like this. MANY THANKS for sharing this, Grant---and our best to both Judith and Kathryn!
 
 
Tom Skilling
 
blog01271001.jpg 
Photos courtesy of Grant, Judith and Kathryn Bevill, Crystal Lake, Illinois
 
Blizzard conditions, the product of 50+ mph winds which sent 4 to 6 inch snow accumulations airborne across Iowa late Monday, slashed visibilities to zero and brought travel to a standstill. In some areas, officials ordered snow plows off highways because of multi-car pile-ups. I-35 north of Des Moines and a section of I-90, from Albert Lea west to the South Dakota border, were closed.

The cold air's return marked the end of a two week break in frigid arctic air which had dominated so much of early and mid January. The latest frigid blast follows on the heels of 44 and 46-degree highs Saturday and Sunday---the mildest temperatures here in the nearly 2 months since early December. The recent mild interlude nudged Chicago's meteorological winter temperatures (the readings logged since Dec. 1) to more than 5-degrees ahead of a comparable period a year ago.

Bursts of snow accompanied the cold air's arrival here producing accumulations of 1.1 inches at south suburban Beecher and Peotone, 1 inch Schneider, Indiana, 0.6 inches Downers Grove and 0.4 in Oak Brook.
   
Disturbance to bring flurries Wednesday; lake snow threat grows with an even colder push late week

Peeks of sun may emerge at times from flurrying clouds by Tuesday afternoon. But a frontal system's arrival Wednesday re-establishes an overcast and ignites a new round of flurries. What follows Thursday and Friday is still colder air which is likely to push nighttime readings near or below 0-degrees outside the city Thursday and Friday night. 
 
Storm projected at present to track to the south, a forecast which will be monitored

That surge of colder arctic air later this week has driven the  predicted track of a storm landfalling on the West Coast Tuesday farther south. If that projection holds up, it would keep the system's biggest snows well to the south of the Chicago area. But, track forecasts will be monitored. Any northward jog in the system's path would bring its snow farther north too.

What seems even more plausible at the moment is the possibility the storm's circulation in combination with a cold Canadian high to the north may encourage snow showers to blow off Lake Michigan into Indiana's snowbelt Thursday---and possibly into Chicago and the Illinois shoreline late Thursday night and Friday.
 
Anniversary of Chicago's worst snowstorm: The Great Blizzard of 1967

It was 5:02 a.m. in the morning on this date 43 years ago that a snowstorm destined to become the Chicago area's worst on record got underway. By the time its blizzard-like snowfall ebbed, the city had been buried beneath 23.0 inches of snow. The infamous Blizzard of '67 brought the city to a standstill, stranding 50,000 cars and 800 CTA buses in drifts on the city's thoroughfares. Only two days before, on Jan. 24, area residents had enjoyed a record-breaking 65-degree high.
 
FEATUREGRAPHIC012610.jpg

2WEEKTEMPFORECAST012610.jpg


How rare are tornadoes in California?

|
Dear Tom,
Recently there were tornadoes in California? How rare is that?

--Mary King, Lisle
Dear Mary,
Since 1950, California has averaged about six tornadoes a year, a far cry from the 125 to 140 each year in Texas or the 27 twisters that typically occur each year in Illinois. California twisters tend to be weak, most of them F0 or F1 on the Fujita scale; not the F4 and F5 monster storms that roam the Plains, Midwest and the South. Even so, they are capable of doing significant damage in a small area. Like any other tornadoes, the California storms occur when cold, dry air collides with moist tropical air, a common situation when strong storms batter the California coast. While the peak tornado season in Tornado Alley is in the spring, most of the California twisters tend to occur in the winter.

Defining "Climate"

|
Climate012610.jpg

The same system that is clobbering much of Iowa with blizzard conditions this afternoon is headed for Chicago.  What kind of impact will this storm have on the Chicago area?  Follow the link below to the WGN Severe Weather Blog for the very latest

 http://weblogs.wgntv.com/chicago-weather/severe-weather/

 

 

Tim's Weather World: Cold Week But Warm Decade

| | Comments (6)

Temperatures will tumble this week as Arctic air returns.  Highs on Thursday & Friday will not get out of the teens.  In the midst of this big chill it might be hard to grasp the fact that this past decade was the warmest globally since 1880.  According to NASA, the decade from 2000 to 2009 was the warmest since reliable data keeping began back in 1880. Global average temperatures have increased about 1.5 degrees Fahrenheit since 1880 according to a statement released by NASA.  Despite that warming, we still experience periods of colder than average weather.  This past December was a good example as much of the U.S. saw bitterly cold weather.  Scientists point out though that the 48 contiguous states only cover about 1.5% of the world's total area.

 

warmdecade.jpgSpeaking of warm...

 

According to NOAA's Climatic Data Center the global ocean surface temperature was the second warmest on record for December going back to 1880.

www.facebook.com/TimMcGillWeatherGuy

 

http://twitter.com/WGNWeatherGuy

Turning point of Winter as February approaches

|

By the end of the week, there will be just one month left in meteorological winter (Dec1-Feb.28). The last week in January signals the beginning of a slow upswing in average temperatures and entry into the last half of the "normal" snow season. Today marks the exact mid-point of Chicago's snow season with 50 percent of the annual average 36.9 inches(125 years,1884-2009) occurring after this date.

First snow, then cold arrives
As low pressure moves off to the northeast, a broad band of low-level moisture and strong westerly winds will follow, spreading clouds and snow or snow showers over northern Illinois today and tonight. Snow should end early Tuesday. With considerable blowing, not much more than an inch total accumulation is expected here. After a storm system passes well to the south brushing the Chicago area with a period of snow Wednesday, the remainder of the week Chicago will rest on the southern flank of an arctic air mass centered just north of the Great Lakes. Temperatures Wednesday through Saturday will average close to 10 degrees below normal.

Last week in January marks turning point in winter

|
FEATURE01252010.jpg

Groundhog Day: Is it accurate?

| | Comments (1)
Dear Tom,
Is there any validity to the legend about Groundhog Day?
Jim Kuypers

Dear Jim,
In American folklore, Groundhog Day is an indicator of the weather for the remainder of the winter. The hibernating groundhog digs out of his burrow at sunrise on Feb. 2, so the legend goes. If he sees his shadow (a sunny morning), he heads back into his burrow, thereby indicating another six weeks of wintry weather. A cloudy morning creates no shadow and the groundhog stays out, indicating an early and mild spring.

In short, "Shadow, go; cloudy, howdy!" The Feb. 2 appearance of Punxsutawney Phil (of Punxsutawney, Penn.) is the most popular of many Groundhog Day celebrations.

Is the legend reliable? The authoritative American Meteorological Society, says, "There is no convincing statistical evidence to support this (Groundhog Day) belief."

Rain melts snow cover, raises flood threat

|
Low pressure and the associated cold front will move east through Chicago Sunday morning. Overnight rains will continue this morning before diminishing behind the cold front this afternoon. The combination of 40-degree-plus temperatures and dewpoints, strong winds and up to an inch of rain should be enough to pretty well eliminate any snow cover over northeast Illinois. Much of this rain and water from snowmelt will run off, causing pooling in low-lying, poorly-drained areas, as well as rises on rivers and streams, many of which are already near bank full.

Cold air and snow follow

As temperatures fall into the 20s, wrap-around snow behind the departing low pressure system will hit early Monday and continue into Tuesday. With blustery northwest winds gusting to 30 mph, there will be considerable blowing, but a thin inch or so coating of snow could accumulate. Cold air will hold the remainder of the week, with a possibility of an accumulating snow reaching into northern Illinois Thursday.

Ice/snow further north

Freezing rain, 40 to 50 mph winds and heavy snow hit North Dakota and northern Minnesota Saturday downing power lines and creating near blizzard conditions. Additional snow will continue over these areas through Sunday.


Record seasonal snowfall for selected U.S. cities

|
FEATUREGRAPHIC012410SUN.jpg

Dear Tom,
What type of weather is most damaging or dangerous to our community?

Zackary Schleyer
Dear Zackary,
Several answers are possible. Let's first consider cost. Surprisingly, the chill of winter is the most costly (though not most damaging) aspect of Chicago's weather because of the unavoidable expense of heating buildings. Regarding a specific kind of damaging weather, excessive rainfall and resultant flooding head the list. More generally, thunderstorms constitute our most costly weather events because they produce lightning, hail, high winds, flooding and tornadoes.
Finally, because weather-related highway accidents claim more lives and cause more injuries than other weather events, weather occurrences that contribute to auto accidents (rain, freezing rain, snow, fog) constitute the most dangerous kinds of weather.

Waves of heavy rain hit late Saturday into Sunday morning and are likely to spell doom for what remains of the city's snow pack. An inch or more of snow has covered the ground at Midway Airport the past 28 days. The snowpack has managed to survive since just after Christmas even with arctic air a no-show the past 11 days.

A wet storm, likely to unleash an inch or more of wind-driven rain across much of the Chicago area as darkness settles in Saturday evening,  spins up on the nose of the same powerful jet-stream-level wind max which has hammered the West with a week-long parade of vicious Pacific storms. The storm headed for Chicago develops over Arkansas Saturday, then lifts north into northern Illinois Sunday morning. Mild air is to rush into the area with the system -- but will be masked for a time in lakeshore areas by strengthening southeast winds slicing off chilly 33-degree lake waters. Rising temperatures and humidities are likely to speed the snow cover's demise Saturday night.  A combination of the snowmelt and heavy downpours is likely to produce tremendous run-off, making standing water a good bet into Sunday. 

The absence of snow isn't likely to last long here. A realignment of atmospheric steering winds is to reinvigorate arctic air, chased into North America's northernmost reaches the past two weeks. The chill is to crash southward over most of eastern North America over the next week. Slow cooling commences Sunday afternoon when temperatures are to back off low and mid 40-degree morning highs, settling into the mid-30s by nightfall. The cooling accelerates amid snow showers Monday when highs may fail to break out of the 20s. By Tuesday and Wednesday, frigid air will be back in full control with highs struggling to reach 20 Tuesday and the low 20s Thursday.

What happens next (mid and late week) will have to be monitored. Computer models suggest a potentially significant eastbound snow system could emerge from the Rockies midweek and swing into at least portions of the Midwest Thursday. The system has the potential of producing accumulating snow.
 
Parade of El Nino storms finally breaks out West

California residents, at the mercy all week of El Nino-enhanced storminess, have seen flooding rains and mudslides, hail with unusually energetic thunderstorms, a series of small but damaging tornadoes, and travel-inhibiting snows in the mountains.  Los Gatos, south of San Francisco, topped late Friday rainfall tallies for the week registering 16.30". Snowfall reached 90" (7.5 feet) at Mammoth Lakes, Calif. -- more snow that Chicago logged in its snowiest winter on record (89.7" in 1978-79). The big snows weren't limited to California. Flagstaff, Ariz., has been buried beneath 53.5" of snow, and heavy snows have occurred in the mountains of Utah, Colorado and New Mexico. Precipitation winds down across the region this weekend.
FEATURE01232010.jpg

Skiing in Hawaii ... on snow!?!

|
Dear Tom,
I believe skiing is possible on the summit of Mauna Kea in Hawaii, but my friends disagree. What is your opinion?

--Roger Harmon

Dear Roger,
You're correct. Air temperatures in the troposphere, the lowest layer of the atmosphere from the ground to 5 to 11 miles aloft, decline about 5 degrees per 1,000 feet of vertical ascent. The 13,796-foot summit of Mauna Kea ("White Mountain" in Hawaiian) is sufficiently high to receive skiable snow several times each winter despite its subtropical location.
Mauna Kea's summit temperatures, ranging from the 20s in winter to the 50s in summer, are never frigid, but winds frequently in excess of 60 mph create dangerous wind chill readings. Skiing is best immediately after a strong, wet frontal system crosses the islands, bringing Mauna Kea a heavy snow. However, the snow melts quickly and ski conditions deteriorate rapidly within a few days.

Heavy snow wallops Flagstaff, Ariz.

| | Comments (1)
We've received some wonderful photos of heavy snow from Flagstaff, Ariz.

The set of photos below comes from Paul Hellenberg, who reports the following:

"Schools and government offices are shut down. We received about 3 feet of snow and NWS Flagstaff is predicting a couple more feet before the end. Interstates 40 & 17 are closed due to heavy snow and blowing snow."

20100122flagstaffsnow01.jpg

20100122flagstaffsnow02.jpg

20100122flagstaffsnow03.jpg

20100122flagstaffsnow04.jpg

20100122flagstaffsnow05.jpg

Photos courtesy of Paul Hellenberg

These next photos show a great "before and after" sequence from Bob Boilini, a former Highland, Ind., resident who now resides in Flagstaff. The picture below is a beautiful shot before the storm...

20100122flagstaffsnowB01.jpg

The pictures below are after the storm; Bob reports that more than 4 feet of snow has fallen so far.

20100122flagstaffsnowB02.jpg

20100122flagstaffsnowB03.jpg

Photos courtesy of Bob Boilini, Flagstaff, Ariz.

Thanks to all who've sent in photos!

Los Angeles and Las Vegas are hardly areas which come to mind as meccas of record-breaking low pressure any more than Phoenix, Arizona is known for regular tornado touchdowns. These are exceedingly rare events in southern California and the deserts of the Southwest--- yet with the atmosphere over the region contorted into an abnormally stormy state by a jet stream bearing winds as high as 260 mph over the Pacific in recent days---velocities all but off-the-charts even at 30,000 ft.---these events were just a few of the weather anomalies which have plagued the West. A battery of four storms which have hit one after another have initiated California mudslides, played havoc with air traffic and buried Golden State mountaintops under 6 or more feet of snow. Gargantuan snowfalls haven't been limited to California's mountains. Measurements at the Grand Canyon in Arizona put Thursday's snow cover at 50 inches---more than 4 feet---and Flagstaff, in the northern section of the state, has been hit by more than 3 feet of snow since the El Nino-influenced storms began arriving.

Rare tornadoes touch down


What may have been a brief tornado touch down in a Phoenix area shopping center 6 miles west of Scottsdale Thursday, is only the latest report of a twister to dip from the West's turbulent skies this week. A Weather Service survey team dispatched out of the Oxnard, California forecast office to check into reports a tornado had touched down in nearby Ventura, hurling a car into trees there, confirmed the touch down. The EF0 intensity twister, bearing 65-86 mph winds, churned along a path a mile and a half long.

Thursday's weather played havoc with air traffic in the southwest. Flights were suspended much of Thursday at Burbank, Ontario and San Diego airports in California as well as at Tucson and Phoenix in Arizona. Winds---even outside of the day's frequent downpour-generating thunderstorms---often gusted above 60 miles per hour.

Rainfall in the hardest hit foothills around Los Angeles grew to more than 14 inches late Thursday while peak wind gusts in recent days have topped 106 mph at higher elevations in the Sierra.
  
The storm which slammed into California Thursday was the fourth in less than a week. It heads for the nation's Heartland and likely to bring Chicago strengthening winds over the weekend and Saturday sprinkles which build into possibly heavy rains at night. The system may deposit as much as 0.50 to 1.25 inches---much of it expected Saturday night into Sunday morning.
 

Chicago's winter among 25 percent coldest--but running milder and less snowy than last winter
 
The dramatic pullback of cold arctic air in the past 11 days hasn't erased the temperature deficit Winter 2009-10 is running to date. Despite overall temperatures at levels 2.8-degrees below the 140-year average since Dec. 1, El Nino has appears to have had some impact. The period is averaging an impressive 4.1-degrees milder the comparable period a year ago and has produced 13.3 fewer inches of snow.

Thundery  6-7-inch rains sweep north Florida
 
The West isn't the only region which has been hit with big rains. Thunderstorms, which towered to heights of 47,000 ft. and swept north Florida and the Southeast Thursday, generated 6 to 7 inches of rainfall in north Florida.

Mammoth western storm heads for country's Heartland

|
FEATUREGRAPHIC012210new.jpg

Potentialsnow012210.jpg


What is El Nino?

|
El_Nino012210.jpg

Dear Tom,
Could the amount of electricity in a lightning bolt power a house?

Ike Anderson
Dear Ike,
It's virtually impossible. Worldwide, lightning strikes the ground about 100 times per second. Lightning expert Dr. Martin Uman explains: "A maximum value for the total electrical power input to worldwide cloud-to-ground lightning is 1,000 billion watts. By comparison, the total capacity of all electric power generators in the United States in 1970 was about 500 billion watts. It is evident, therefore, that the power and energy available to lightning is appreciable."
Unfortunately we cannot capture that energy, for two reasons. It is impractical to capture any appreciable number of ground strikes; secondly, most of the energy in a stroke is converted along the lightning channel to thunder, heat, light and radio waves. Little energy remains at the channel base for capture and storage.

Iowa and sections of central Illinois bore the brunt of an ice-storm which only lightly glazed sections of the Chicago area Wednesday and Wednesday evening. Weather spotters across the south and west suburbs reported the heaviest accumulations of ice, including 0.2 inches at Portage, Indiana and 0.1 inch near Kankakee, Peotone, Pontiac and the northwest suburban town of Winnebago in Winnebago County. Precipitation began south of Chicago mid-afternoon and had worked into the city as the evening rush hour got underway. With temperatures hovering at or just below freezing, road chemicals were able to work at maximum efficiency and there were few problems reported on metro area thoroughfares. The scene was a very different one farther west. Icy morning roads led to the closing of schools in west central Illinois' Macomb. Freezing rain proved even more formidable across Iowa and into eastern Nebraska and sections of southern Minnesota. Hardest hit was the area west of Des Moines where as much as 0.8 inches of ice coated the landscape taking down large 10 to 12 inch diameter tree limbs in strong 30+ mph wind gusts. Power was knocked out to thousands of Iowa homes.

The system behind the wind and ice across the Midwest  was the first to ride the rare 240+ mph jet stream into the West Coast just three days ago. Sprawling Pacific storms which lambaste California and the West Coast are common features of El Nino cold seasons. This season's storms have been late in arriving. It's not uncommon for El Nino storm barrages to get underway in December.

The stronger than usual "SUB-TROPICAL" (southern) jet streams fostered by El Ninos lead to many of the events' most common winter weather abnormalities across the Lower 48 states, among them wetter than normal weather across the desert Southwest and active severe weather outbreaks across the Deep South. Both were in evidence Wednesday. Waves of downpour-generating thunderstorms produced 16 reports of tornadoes across sections of Texas and Louisiana.
 
 
California continues taking meteorological beating from El Nino-powered storms
  
The meteorological assault on California continued Wednesday. Electricity to 27,000 Sacramento area customers was out as a rare barrage of winter thunderstorms produced power line-downing wind gusts as high as 60 mph. Winds hit 59 mph at San Francisco and 61 mph at Elk Grove, just southeast of Sacramento. Even stronger winds have been clocked in recent days.    Velocities  as high as 104 mph whipped the crest of the state's Sierra range at Ward Mountain.

An automated Snotel sensor at Chagoopa Plateau reported snowfall since the parade of storms began late this past weekend had reach 73.6 inches---more than 6 feet---Wednesday. Snow and ice forced the closure of I-5 at the 4,100 ft. level of Tejon Pass east of Los Angeles. And two Southwest Airlines jets were struck by rare lightning Wednesday at the arrival gate of Burbank's Bob Hope Airport Wednesday.

Monterey California typically see three thunderstorms in an entire year---but six have swept the city in just the past three days.
 
 
Colder pattern threatens return of sticking snow beyond weekend
 
Computer models indicate sticking snow may return to the Chicago area over the coming two weeks. The twelve most recent runs of the National Weather Service's Global Forecast System model have generated total 2 week snowfall estimates averaging 6 inches.

Winter storm watches have been hoisted for the northern Plains beginning Friday night, continuing through much of the weekend. A foot or more of snow may occur there as another of the El Nino strengthened storms jumps the Rockies and spins into a formidable winter system likely to rain on Chicago---but expected to snow across the Dakotas and northern Minnesota.
FEATUREGRAPHIC012110.jpg

Snowoutlook012110.jpg

Ice crystal precipitation

|
Dear Tom,
On a totally clear (no clouds at all) and cold morning with the temperature at zero degrees, I noticed snow crystals in the air. Does this kind of snow without clouds have a name?

Bob Johnson, Buffalo Grove

Dear Bob,

It was not snow that you observed but a particular kind of precipitation known as ice crystals. They consist of exceedingly tiny, almost microscopic, particles of ice, usually in the form of needles, that slowly fall from a cloudless sky. Their fall speed is so slight that individual crystals appear to float in the air.

When illuminated by sunlight (or by moonlight or artificial light at night) they sparkle and glitter quite spectacularly and for that reason are also known as diamond dust.

Ice crystals form in very cold air, usually at subzero temperatures, that is also nearly saturated (relative humidity approaching 100 percent).

These are amazing pictures of the aftermath of the crippling Christmas blizzard which swept the Plains between Dec. 23 and 27, producing up to 2 feet of snow (40 inches in sections of western South Dakota) whipped by winds in excess of 70 mph in huge drifts. The storm impacted all forms of travel, closing highways and Interstates--even delaying train travel on the Amtrak system between Omaha and Denver. These pictures relayed to us by Eric Johnson, a colleague of mine at WGN and one of our talented directors, were taken by Mel Wilson.  In passing along these amazing photos, Mel writes: 
 
""These photos were taken on the Bellwood Subdivision, between Seward and David City, Nebraska on the BNSF RR, my employer. Seward is about 25 miles west of Lincoln, on the Ravenna Sub. A few blizzards and sub zero temperatures coupled with moderate winds made for a beautiful, but, flash frozen environment. A freight train was snowed in at David City and a rotary snow plow was sent to clear the track of drifts that varied from 6ft or less up to 12 ft in spots!! The photos were taken on Jan. 8th through Jan. 10th."
 
 
Amazing shots! Many thanks Eric and Mel!
 
Tom Skilling
 

rotaryplow0120109.jpg

rotaryplow01201001.jpg

rotaryplow01201002.jpg

rotaryplow01201003.jpg

rotaryplow01201004.jpg

rotaryplow01201005.jpg

rotaryplow01201007.jpg

rotaryplow01201006.jpg

rotaryplow01201008.jpg

rotaryplow01201012.jpg

rotaryplow01201014.jpg
Photos courtesy of Mel Wilson in Nebraska and Eric Johnson in Chicago











Freezing rain advisory for much of the Chicago area

|

A Freezing Rain Advisory is in effect from 3PM today until 6AM Thursday.  For the very latest on the icy precipitation follow the link below to the WGN Severe Weather Blog

 http://weblogs.wgntv.com/chicago-weather/severe-weather/

Tim's Weather World: Haiti Before & After Images

|

 NOAA, the National Oceanic and Atmospheric Administration, is helping in the relief effort in earthquake-torn Haiti.  The agency is flying a Cessna Citation II over the country to collect high-resolution images that will help responders assess damage on the ground and give them an idea where to concentrate their efforts. 

            Before  HaitBefore.jpg                                                        HaitiAfter.jpgAfter

 

 

 

 

  

NOAA has provided this type of help after other natural disasters such as hurricanes and tsunamis.  The National Weather Service is a part of NOAA. To find out more about NOAA's mission in Haiti, check out

http://www.noaanews.noaa.gov/stories2010/20100119_haiti.html.

www.facebook.com/TimMcGillWeatherGuy

 

http://twitter.com/WGNWeatherGuy

 

featuregraphic012010.jpg

Chicagoans have learned through hard experience winters here can be vicious. But a cold blast of the intensity of the one which hit 25 years ago remains in a league all its own. To this day it is the coldest spell of weather ever to grip the city. Temperatures that brutal 1985 morning plunged to 27-degrees-below zero amid 15 to 30 mph winds which generated a 77-below wind chill. (The wind chill index has since been revised and the same combination of wind and temperature would result in a still almost unimaginable 57-below wind chill today).

Never before Jan. 20, 1985 had a morning been so cold. Trees and buildings crackled in the bitter arctic air and movement in the city slowed to a crawl as cars and other vehicles failed to start in a level of chill which physically hurt.

That a 27-below reading was even possible here was surprising to many. Chicago's official temperature records date back to 1871--and there had NEVER been a reading as cold before. The mid and late 1970s produced a series of intensely frigid cold seasons and one---the 1978-79 season---delivered snow with such frequency, it was widely credited with producing a January blizzard which sent Mayor Bilandic packing, allowing Jane Bryne to move into City Hall. The season ended up the snowiest here ever with a total of 89.7 inches to its credit by the time it closed.

Collectively, the winters of the 1970s were the worst of any in more than a century of weather records. Then came Jan. 10, 1982 and the mercury slipped to the city's new all time low: -26-degrees with 40 mph wind gusts which pushed wind chills to an unimaginable 90-below. It was, area residents were told at the time, a once in 300 year event climatological event. Only a week later, readings slipped to -25-degrees, challenging the assertion. But it was this date in 1985 which ended up producing Chicago coldest temperature ever: -27-degrees.
  
Wednesday dawns nearly 50-degrees warmer. The first in the  series of stormy weather systems which have crashed onto the West Coast in recent days onboard a 200 mph jet stream, is bearing down on the Midwest and threatening freezing rain and ice. Ice storm warnings cover a good chunk of Iowa Wednesday into Thursday and freezing rain advisories have been hoisted in central and western Illinois.

Chicago's thickening Wednesday overcast precedes the disturbance and will hide the sun in time, bringing the area some freezing rain Wednesday night and Thursday. The system is to produce this area's strongest winds in a week. A more impressive storm follows this weekend and could douse the area with rains which begin in light, scattered patches Saturday and crescendo into heavier downpours Saturday night. 

There are growing indications cold air regains its control of Midwest weather next week. Scattered rain Sunday may switch to snow or snow showers Sunday night into Tuesday---and recent longer range computer projections into the 1 to 2-week time span suggest sticking snow is to become increasingly likely in the Chicago area and over a wide swath of the Midwest.

California blasted by powerhouse El Nino-enhanced storms; twisters, thundery downpours, 90+ mph gusts and huge mountain snows result
 
Tornadoes and severe thunderstorms swept ashore within the latest in a string of powerful Pacific storms Wednesday. Additional storms are expected to continue slamming into the West Coast the remainder of the week. California is at the epicenter of the meteorological assault. Three twisters were reported in the Los Angeles area Tuesday, including one which touched down at Huntington Beach, tossing boats 20 to 30 feet into the air and flipping a limo and SUV.  Lifeguards at nearby Newport Beach clocked 93 mph thunderstorm gusts. Winds reached 100 m.p.h. and rains approached 5 feet in the region's mountains and foothills. A 64 mph gust swept San Francisco's famed Golden Gate Bridge while 75 mph gusts occurred just north of the central California metropolis. Snowfall near Lake Tahoe approached three feet.

A phenomenal jet stream, boasting peak winds of 246 mph and strengthened by a huge north-to-south temperature spread between -60-degree Siberian temperatures to the north and El Nino-warmed air and water extending from western South  America westward nearly the length of the equatorial Pacific, is powering the storm eruption. 200+ mph winds extended late Tuesday more the 4,000 miles from the Baja California coast to the ocean waters east of Japan.
 


 

The term "hoarfrost"

|
Dear Tom,
The last few days I've heard the term "hoarfrost" being used. Where did that term come from?

-Daniel Miller

Dear Daniel,
Hoarfrost is the direct deposition of atmospheric moisture in the form of interlocking ice crystals on objects like wires, poles, tree branches and plants without the moisture ever passing through the liquid phase. It usually forms on clear, calm nights when the air temperature is below freezing. When low-angle sunlight illuminates the frosty landscape during the early morning hours, the views can be breathtaking, giving an area a fairyland-like appearance. The term hoar is a reference to the frosty coating and comes from the word hoary which means white or gray with age or showing characteristics of age, especially having white or gray hair.

Sharyne Tu sends along these incredible shots of Chicago's skyline as it look above the weekend cloud deck trapped beneath the strong temperature inversion in place now for days. Included among Sharyne's photos are lake ice shots taken near her home on Chicago's far North Side.  THANKS so much for sharing these with us Sharyne!!
 
 
Tom Skilling


011910chiclouds.jpg 
Chicloudsky011910.jpg


ice01191001.jpg

ice01191002.jpg

ice01191003.jpg
Photos courtesy of Sharyne Tu, Chicago
 





City skyline as snapped Sunday in the O'Hare landing pattern

|
What great shots!  These come to us from Joe Neville who tells us:
 
"I took a few photos with my i-phone Sunday as my plane circled in over Lake Michigan for landing at O'Hare.  There seemed to be a slight fog of some sort over the city as we approached the lakefront."
 
Joe's captured the sharp temperature inversion in place much of the past week. The relatively shallow haze and cloud layer marks the inversion, which involves a layer of comparatively cold, dense air just 2,000 to 3,000 ft. deep on top of which sits milder air, according to weather balloon measurements  THANKS for sharing these photos with us, Joe!
 
Tom Skilling
 

 
skyline01191001.jpg

skyline01191002.jpg
Photos courtesy of Joe Neville, Chicago


Bryan Pitstick sends us this photo taken near Copper Harbor in Michigan's Upper Peninsula this past Saturday (1/16/2010). He tells us it was 45-degrees and sunny compared to the 20s through which northern Illinoisans shivered!

THANKS for a beautiful shot, Bryan!

Tom Skilling

011910snowmobile01.jpg
Photo courtesy of Bryan Pitstick 

The area's been mired beneath clouds most of the past 5 days. Sun-blocking clouds have been trapped in place by an atmospheric setup referred to by meteorologists as a "temperature inversion."  Inversions occur when temperatures warm with height rather than cool as is typically the case. An INVERSION---as its name implies---is a "reversal" in the normal temperature distribution with height.  When that occurs, any attempt of moist air in the lowest reaches of the atmosphere to rise and mix with drier, cloud-dissipating air is impeded. In the absence of winds carrying drier air into the area, any clouds already in place frequently survive. That's what's been happening here in recent days.

Chilly air, saturated with moisture from melting snow over the past week and only about 2,400 feet deep, has supported widespread cloudiness. At times in recent days, the cloud deck has been so shallow that the tops of the city skyline has been visible to pilots and  airline passengers flying into the area---even as street-level observers have looked up to see the tops of buildings shrouded in clouds.

One result of the persistent cloud cover has been to block the sun. Chicagoans have seen just 17 percent of the area's possible sunshine over the past 5 days--an amount well below normal. Another impact has been the proliferation of tiny super-cooled water droplets in the haze and fog so often a part of the local weather scene of late. Water is said to be "super-cooled" when it remains in liquid form even when its temperature is below freezing. Super-cooled droplets quickly freeze into a layer of ice or ice crystals upon contact with any cold outdoor surface. That process is behind the spectacular hoar frost displays of recent days---the eye-catching layer of ice crystals which have covered trees, shrubs, fences, picnic tables, sheds, barns, and virtually every imaginable outdoor surface.

Some drying of the lower atmosphere Tuesday may permit clouds to thin out and at least some sunshine to emerge. Light winds are predicted and may be a drawback to any clearing.  Clouds can be slow to dissipate when light winds are present.

First of El Nino storms on West Coast unleashes 1-4 inches of rains,  gusts to 80 mph
 
Clues of Chicago's weather pattern later this week are evident on the West Coast and desert Southwest. The first in what promises to be a week-long wave of powerful Pacific storms embedded within an extraordinarily strong 230+ mph jet stream hammered California Monday. Severe thunderstorms there unleashed 80 mph wind gusts at a few locations while slopes, denuded by summer wildfires, grew waterlogged, threatening mudslides. Though conditions eased late Monday, additional waves of storminess are on the way. By the time the week ends, 20+ inches of rain threatens to fall on the hardest-hit westward facing mountain slopes while snows at higher elevations may be measured in yards rather than feet.

The first of a series of disturbance expected to jump the mountains and reform to the lee (east) of the Colorado Rockies Tuesday threatens to churn eastward into Missouri and Illinois by Thursday. A huge pressure variation between that system and a strong, chilly Canadian high to the north is predicted to produce strengthening winds in Chicago Thursday. The flow threatens to tug cold air in at lower atmospheric levels as moisture-rich air rides up and over. It's a setup which may lead to freezing rain or a mix of freezing rain and sleet Thursday which would trend to all rain by Friday.

A stronger system is due with additional rain here Saturday into Sunday. The cold air that system may drag into the Lower 48 on its back side Sunday night into next week could bring snow to the Chicago area later Sunday night and Monday.
 
 



 
FeatureGRAPHIC011910.jpg


"Air pockets" in aviation terminology

|
Dear Tom,
I just flew to Chicago from Seattle and the flight was quite turbulent. I overheard a passenger saying it was because of "air pockets." What is an air pocket?

Steve Capurro

Dear Steve,
Air pocket is a term from the early days of aviation, and it originally was applied to downdrafts because it caused an airplane to drop suddenly. Pioneering pilots imagined those downdrafts to be "pockets" in which there was insufficient air to support the plane. It is now known that localized downdrafts are a common occurrence, even in clear air. They can cause a rough flight even for today's powerful jet aircraft.

In modern aviation terminology, an air pocket has three meanings: a local downdraft, an abrupt reduction of an aircraft's headwind or an abrupt increase in its tailwind, all of which can cause the craft to drop suddenly.

A dusting of frozen fog crystals

|
Carolyn Szepanski sent us these pictures from Whiting, Indiana. She tells us:

I took a few pictures Sunday afternoon of the frozen fog crystals from Whiting, IN. The minute crystals were floating around in the air, like very fine ash, and left a pretty dusting on everything.

 
Thanks for the great shots Carolyn!

picture011910t03.jpg

picture01191002.jpg
Photos courtesy of Carolyn Szepanski , Whiting, Ind.
Many thanks to Steve Newlin of Gurnee who snapped these incredible shots of the hoarfrost which coated the Devils Head Ski Resort in southern Wisconsin Sunday morning. They are beautiful!  Thanks for sharing them with us Steve!
 
Tom Skilling
 
devilshead01181002.jpg

devilshead01181001.jpg
Photos courtesy of Steve Newlin, Gurnee, Illinois



Beautiful winter scenes

|
Val O'Sullivan and his son sent us these pictures from Rockton, Ill.
januarywinter01181001.jpg

januarywinter01181003.jpg



---


Josh Keating from bonfield, Illinois sent us these pictures of the freezing fog taken Sunday:

freezfog01181001.jpg 

freezfog01181002.jpg


---

Claire Obrecht from Schaumburg sent us a shot of the scenery in Busse Woods:

woodsfor01181001.jpg

---

Brittany Svee sent us these shots fromin Lockport, Illinois:

01181003.jpg

01181002.jpg

01181001.jpg

---

Dave Nikolai sent us these pictures from Wisconsin. He tells us:

"We woke up this morning to a decent accumulation of hoarfrost in Burlington, WI. .. The scenery was spectacular, especially when the sun broke through the fog about 11am.  I was also able to capture a picture of a fogbow
"

fogbownshed01.jpg

fogbownshed02.jpg

Tim's Weather World: Fabulous World of Freezing Fog

| | Comments (3)

The past couple of mornings have featured a weather phenomenon that is not seen that often.  Freezing fog has made for some nice "Kodak moments" but it can also create slick spots and make travel tricky.  We might see more of it early tomorrow.

HoarFrost2.jpgRemember that fog is basically a cloud near the ground.  Water vapor in that cloud turns directly into ice crystals and forms on the surface or objects near the surface.  It occurs when the air near the surface has dew points below the freezing mark.  The result is called hoar frost. 

For more discussion on freezing fog, check out:

http://www.its.caltech.edu/~atomic/snowcrystals/frost/frost.htm

 

You can find me on facebook and twitter at-

 

www.facebook.com/TimMcGillWeatherGuy

 

http://twitter.com/WGNWeatherGuy

Much more clouds than sun in Chicago's forecast this week

|
While there will be some periods of sunshine, cloudiness will prevail much of the week ahead over northeast Illinois. Today will start off similar to Sunday, with clouds, fog and haze trapped under a persistent low-level temperature inversion (temperatures increasing with height). Similar to Sunday, the heat given off in Chicago should help improve visibilities and allow some sun to break through, while areas away from the city under a thick snow cover will again be much slower to improve. Veteran weather observer Frank Wachowski reported the sun broke through late Sunday morning at Midway Airport, and his equipment actually recorded 369 minutes or 65 percent of the possible daily sunshine.

Until next weekend, low pressure will be holding south with Chicago on the northern edge of cloud cover and precipitation.
 
Storms hit the California coast
The first in a series of storms hit the California coastline Sunday with rain (and snow at higher elevations) overspreading that state. This week a 230 mph jet stream will repeatedly fling strong low pressure systems at that same area in 24- to 36-hour intervals. By the end of the week a total rainfall of 4 to 8 inches is expected along and immediately inland of the California coastline as well as into much of Arizona. The foothills could see from 10 to as much as 20 inches of rain with mudslides likely in recent burn areas. Above 5,000 feet, several feet of heavy snow along with 70 to 100 mph winds will slow travel to a crawl.

FEATURE01182010.jpg

Icicles on rooftops

| | Comments (3)
Dear Tom,
Driving around this past week, my husband and I noticed a lot of icicles, but they aren't uniform on homes: Some have them, some don't; some it's only on half the house. What causes icicles and how do they form? Why do some homes have a lot of them and some have none?

Betsy Summers, Glen Ellyn

Dear Betsy,
Icicles hanging from the roof of a house are a visual indicator of heat that has escaped through the structure's roof system. Broadly speaking, they are a reminder that the roof lacks sufficient insulation.
Icicles form when heat escaping through the roof melts snow that has accumulated on the roof. The resulting water drains down to an unheated portion of the roof (the overhang or the gutter system) and refreezes. Water dripping over the gutters freezes into icicles. Many other factors affect icicle formation, but the quality of roof insulation is the key.

Hoar frost in Romeoville

| | Comments (1)
Tom Powers of Romeoville shares these incredible pictures he took Sunday morning of hoar frost. Away from Chicago, hoar frost formed on branches, plant stems and wires--creating a beautiful wintry scene. Hoar frost--the deposit of interlocking ice crystals--forms in a similar fashion as dew except temperatures are below freezing, and the sublimation process changes vapor directly into a solid phase.

Thanks Tom for the wonderful photos!

20100117frostinromeoville01.jpg

20100117frostinromeoville02.jpg

20100117frostinromeoville04.jpg

20100117frostinromeoville05.jpg






Portions of the Chicago area may see the sun today...

| | Comments (2)

Tired of the fog and grey skies?  The Chicago area stands a little better chance at a few rays of sunshine today than we did yesterday.   Or you could rise above the clouds. 

For the very latest on Chicago's weather this Sunday morning, follow the link below to the WGN Severe Weather Blog.   Or, you can always Google "WGN severe weather blog".

http://weblogs.wgntv.com/chicago-weather/severe-weather/

Chicagoans experienced a cloudy chilly damp day Saturday. High temperatures were 10 degrees below forecasts, hitting only 28 degrees at Midway Airport with just 27 degrees recorded at the official O'Hare observation site. All the warmth and action occurred between 2000 and 3000 feet aloft over the city where southwest winds brought in 40+ degree air, establishing an extraordinary temperature inversion where readings increased from near 20 degrees F at 2000 feet to 45 degrees F at 3000 feet above the ground. The term "inversion" is used meteorologically to describe atmospheric conditions where temperatures actually increase with height instead of the normal decrease. The dense snow cover below along with light winds created this unusually stable environment that did not allow even a little of the normal mixing of air aloft with that on the ground.

Storms set to pound west coast


A 200 mph jet stream will direct a series of storms into the west coast during the week ahead. Total rainfall could range from 4 to 8 inches along the coast up to 10 to 20 inches in the foothills. Heavy snow will fall in the mountains, beginning at about the 5000 foot level. Snow accumulations up to 10 feet are forecast and that along with winds approaching 100 mph in mountain passes and higher terrain will create blizzard conditions bringing travel to a standstill.

 
WX-FEATURE011710.jpg

Dear Tom,
Regarding your recent column about melting snow, I moved here from Denver and have observed that Chicago's snow seems to melt faster than the fluffy "skiing snow" that falls in the mountains near Denver. That is not what one would expect. Am I not observing things correctly?

-Sam Graf

Dear Sam,
You're correct, but it's a complex issue. Mild, moist air melts snow more quickly than mild, dry air at the same temperature. Chicago's air tends to contain more moisture than Denver's air. But there's another factor: Sunlight can penetrate more deeply into "fluffy," low water-content snow ("skiing snow") and its heat energy is distributed through a deeper snow layer. This slows the melting process. Sunlight does not penetrate Chicago's more dense snow, and its heat is concentrated at the surface, speeding the rate of melting.  

What a difference a week makes in Chicago

| | Comments (1)
Last weekend the upper-level steering wind flow was straight out of the north, directing cold air from the arctic regions of northern Canada directly into the Midwest and western Great Lakes. High temperatures last Saturday and Sunday were 22 degrees and 18 degrees respectively, averaging about 10 degrees below seasonal normals. This weekend the upper-air pattern has evolved significantly, taking on a more El Nino look. Steering-level winds are westerly with the Pacific Ocean as a source region, the Rocky Mountains providing a drying-out mechanism, and the major storm track is far to the south. As a result, high temperatures this weekend will reach the upper 30s, some 10 degrees above normal.
 
Rains confined to opposite corners of the nation
A major low pressure system has developed in southern Texas and will move northeast through the southeastern Gulf Coast states this weekend. Heaviest rains on the order of at least 2 to 3 inches will occur along a corridor from approximately New Orleans to South Carolina. At the same time, the first vestiges of a series of storms developing under a 200-plus mph jet over the Pacific Ocean and targeted to batter the West Coast all of next week will hit the Pacific northwest with an inch or more of rain this weekend.
FEATURE01162010.jpg

January as winter's mildest month

|
Dear Tom,
Has any year produced a January that was the warmest of the three months of meteorological winter for that season?

Nick Recchia, River Grove

Dear Nick,
January, with an average temperature of 24.4 degrees, is the winter's (and year's) coldest month, followed by February (27.9) and December (28.9). Those are long-term averages, but weather-wise Chicagoans understand that, in the city's volatile climate, they don't live with averages; more often than not, day-to-day temperatures consist of wide fluctuations above and below the averages.
That holds for monthly average temperatures as well. A scan of 139 years of Chicago temperatures shows that December has been the winter season's mildest month 74 times (53 percent of the winters), January 17 times (12 percent) and February 48 times (35 percent). Most recently, the winter of 2005-06 featured January as its mildest month.

Tim's Weather World: Flying High to Improve Winter Forecasts

|

The National Center for Environmental Prediction will station jets in Japan for the next few months in an effort to help improve winter forecasting.  The Gulfstream IV aircraft will fly over the data sparse Pacific to collect data on atmospheric conditions there and then feed that data to computer models. 

gulfstream2.jpgThe plan is to "fill in the gaps" where data is short and improve the accuracy of winter forecasts.  The planes that are normally known for investigating hurricanes flew similar missions in early 2009.  They flew over 300 flight hours and the equivalent in miles of circling the earth five times.  

www.facebook.com/TimMcGillWeatherGuy

 

http://twitter.com/WGNWeatherGuy

 

Chicagoans gaze out at a cover of snow for a 21st consecutive day Friday. The milder temperatures which have arrived in recent days have begun melting snow here in the city---but slowly. Two inches disappeared in Thursday's snow-eating 40-degree temperatures. (The readings were the warmest here in the three weeks since a Christmas high of 43 degrees.) The melt decreased the city's snow depth at Midway Airport to just 3 inches according to veteran National Weather Service observer Frank Wachowski--an amount below the 5 inches measured only a day earlier--but a fraction of the 10 inches which was down in the area a year ago when the mercury rose no higher than -1-degree at O'Hare and +1 at Midway. The readings were the coldest of last winter.

Clouds are to shroud area skies much of Friday, though the shallowness of the moist layer in which they're forming hints some breaks may form allowing at least passing sunshine. For most of the Chicago area, a combination of reduced sunshine over the still-extensive snow cover argues for Friday highs a few degrees below Thursday's 40-degrees at O'Hare, 41 at Midway and 43 on Chicago's lakefront.

The critical role that snow plays in regulating daytime temperatures was on  display Thursday.  While the city hosted highs in the low 40s, the heavier suburban snow pack limited highs to 35 at northwest-suburban McHenry, 34 Rochelle, 37 De Kalb and Kankakee, 36 Morris, and 38 at Valparaiso.

Mild air resurges this weekend with 40-degree highs likely

With clouds expected to exit Saturday and stronger west to southwest winds likely to mix mild Pacific air down to the surface later Saturday morning and afternoon, the resurgence of 40-degree weekend temperatures appears a good bet. A cold front will approach the area with increasing clouds Sunday.  But the pileup of air which occurs just ahead of converging southwest and northwest winds along the front is expected to produce some "compressional warming"---an increase in temperature which occurs when a gas--in this case, the air we breath---is squeezed or "compressed" as winds of different direction collide.


Updates computer model forecasts introduce colder air early next week


Next week isn't likely to be as mild as earlier predicted. Newer forecasts have revised predicted highs Monday through Wednesday lower. While not even close to the temperatures area residents have braved much of the past three weeks, the modest new round of chilly air eliminates prospects for additional 40s the first half of the week---developing instead chilly winds off Lake Michigan Tuesday and Wednesday.

A Midwest disturbance expected to emanate from a parade of windy, potentially flooding West Coast storms capable of producing rains as heavy as 10 to 30 inches on some westward facing California mountain slopes next week could arrive in the Chicago area with a "cocktail" of wintry precipitation mid-week.

WX-FEATURE011510.jpg

Resurgingcold011510.jpg


WX-FEATURE011510.jpg

Resurgingcold011510.jpg

Melting snow and temperatures

|
Dear Tom,

My brother-in-law sent photos of 18-plus inches of snow covering his lawn in suburban Baltimore, but temperatures quickly warmed and Baltimore's snow was virtually gone a week later. Since we here in Chicago are hard pressed to get our temperatures up with snow pack on the ground, how could they melt all that snow so quickly?


Sylvia Cordes

Dear Sylvia,

Mild, moist air did the trick. Snow sometimes covers the ground hundreds of miles in all directions from Chicago and mild, "snow-melting" air is greatly chilled as it approaches. Baltimore, however, sits near the Atlantic Ocean and mild oceanic air has easy access to the city.

Moisture is also a big factor because moist air contains far more heat than dry air at the same temperature. Mild, moist air melts snow much more quickly than mild, dry air. Oceanic air blowing across Baltimore from the Atlantic is both mild and very moist.

Hats off to Jerrold Petrizzo of Lemont for this amazing shot taken back at the time of the full moon on December 29. Jerrold has managed to capture an in-flight jet passing across the face of the moon.  Commenting about the photo in his e-mail to us, he says:s
"It is very rare to get a picture with a jet plane going through the center of a full moon. "
 
 
You are SO RIGHT! What a GREAT SHOT! Thanks for sharing it with us, Jerrold!
 
Tom Skilling
 
moonjet011410009.jpg
Photo courtesy of Jerrold Petrizzo, Lemont, Illinois

A string of 314 consecutive hours of sub-freezing temperatures--the equivalent of 13.1 days---finally came to an end in Chicago Wednesday. The official thermometer at O'Hare registered at 12:21 p.m. its first 32-degree reading since New Year's Day. By mid-afternoon, a high of 35-degrees was on the books at the site. It was January's warmest reading to date and marked the first time in a stretch of nearly 20 days extending back to Christmas (Dec. 25) that daytime reading in the city had managed to break above freezing. Adding to the collective sigh of relief the warming produced across the metro area was the day's abundant sunshine. Wednesday hosted 100 percent of its possible sunshine making it the sunniest single day in 7 weeks.

Signs the tenacious arctic air mass behind much of the country's relentless streak of chilly air was losing its grip on the of the Lower 48 continue to grow. Satellite images were able to track the slow demise of the nation's expansive snow pack. National Oceanic and Atmospheric Administration (NOAA) scientists estimated that while 61 percent of the Lower 48 sat beneath a snowy veil Sunday, snow coverage had shrunk by 10 percent to just half the U.S. land mass Wednesday. 
 
Biggest chill in decades finally easing after setting duration records in Florida
 
Across Florida and the Deep South, as damage to vegetation and crops--not to mention countless vacations taken by the winter weary who had headed south hoping to escape winter's wrath--was being evaluated, temperatures finally began a slow ascent from one of the region's most stubborn cold outbreaks in decades. A storm, which promised to deliver warmer south winds, began taking shape in the western Gulf of Mexico.

Sunshine State residents and visitors in Miami, West Palm Beach and Fort Myers rose Wednesday to a record-tying 12th consecutive morning with sub-50-degree temperatures while Gainesville and St. Simons Island, Ga. near Jacksonville, logged a record-breaking 12 days of sub-freezing readings. Every Florida weather station has registered temperatures 12-16 degrees below normal since Jan. 1.
 
 
Increased certainty storms threaten the West Coast with drenching rains next week

 
Evidence that formidable, wind-driven rainfall and high altitude snows are likely to lambaste the West Coast and Southwest next week became even more impressive Wednesday. Computer projections of potential rainfall in the coming two weeks--much of it to fall in an impressive parade of El Nino-strengthened storms next week--indicate more than 8 inches of rain may be on the way in sections of California. Such tallies would eclipse all the rain which has fallen to date since Oct. 1 in Los Angeles , San Francisco and San Diego. The heavy precipitation  appears likely to extend into the Desert Southwest as well.
WX-FEATURE011410.jpg

February blizzard in an El Nino year?

|
Dear Tom,
Predictions from alleged "psychics", included a huge February blizzard for Chicago similar to the 1967 storm. Is that possible in an El Nino year?

Jana Ricketts  Westchester

Dear Jana,
Though Chicago's "El Nino winters" tend to be mild and tranquil, harsh winter weather can still occur though usually with shorter and less frequent doses. About 60 percent of Chicago's El Nino winters deliver above-normal temperatures and below-normal snowfall, which means that 40 percent bring normal or above normal bouts of snow and cold. Despite an ongoing El Nino this winter, snow and cold have been prevalent, with a milder trend only now beginning to surface. A paralyzing blizzard in Chicago would almost always come from a southern storm track--the predominate pattern in an El Nino winter--so it is certainly possible.

Mario Ortiz sent us these great pictures taken in Michigan.

Thanks Mario!

011410DSCF0088.jpg


011410DSCF0086.jpg
Photo courtesy of Mario Ortiz

Frost on the windshield in the Miami area of south Florida

|
These photos of ice on his car windshield in south Florida come to us from Marshall Huffman, one of our hard-working former WGN weather interns who now works at the National Hurricane Center just outside Miami. It's unusual to see frost so far south in Florida.  The icy covering is a product of the record long cold snap which has gripped Florida much of the month damaging plants and crops. Florida has experienced temperatures this cold before--but itS persistence sets cold blast aside in a league all its own. Many thanks Marshall for the great photos and hope you're managing to stay warm!

--Tom Skilling

0114100111000716.jpg


0114100111000715.jpg
Photos courtesy of Marshall Huffman, Miami area of south Florida


Tim's Weather World: Hurricane Prone Haiti

|

Our thoughts and prayers are with the people of Haiti as they attempt to recover from their devastating earthquake.  Earthquakes aren't the only natural disasters Haiti experiences.  Their place in the Atlantic many times puts them in the direct path of tropical storms and hurricanes. 

  Haitihurricane.jpgThere have been seven hurricanes to affect the region since 2008 with combined damage of nearly one billion dollars.  Four storms hit Haiti in 2008 alone.  Hurricanes Gustav and Ike and tropical storms Hanna and Fay struck during August and September that year killing nearly 800 people.

If you would like to help the earthquake victims in Haiti, here are a couple of organizations to check out:

http://www.redcross.org/

http://www.samaritanspurse.org/

http://www.worldvision.org/

To follow me on Twitter or Facebook, check out:

www.facebook.com/TimMcGillWeatherGuy

http://twitter.com/WGNWeatherGuy

 

Chill of past 3 weeks coldest in 11 years--but breaking

|
Arctic air is in retreat and not likely to occur here again until after next week. While winter's chill is hardly history--there are indications colder air may stage a comeback during January's final days in the week which follows-- the welcome development Wednesday closes the book on one of the coldest mid-winter periods in the Chicago area of the past 11 years. Since Dec. 26, the city's temperature has averaged 16.7-degrees--well below the 25.4-degree reading considered typical. Not since the 1998-99, cold season when readings averaged 13.6-degrees, has a comparable 18-day period been any colder. 

But as chilly as the just completed near-three week spell has been, the meteorological winter season which began Dec. 1 is still running 1.5-degrees milder and nearly 10 inches less snowy than a year ago---28.3 inches this season versus 38.2 inches to date last year.

Temperatures surge above freezing Wednesday for the first time in the 20 days since Christmas' 43-degree high. The "warmth" comes on the heels of Tuesday's 31-degree peak reading---January's first above normal daytime high. It will establish a new high for the month, which until Tuesday, hadn't managed a reading above 30 degrees. On Thursday, afternoon readings appear poised to flirt with 40-degrees and are likely to do so at times next week as well. Historically, temperatures at or above 40 have occurred in 93 percent of Januarys and weather history reveals the year's opening month averages seven days with peak readings of 40-degrees or higher.
 
 
Increasingly stormy Pacific indicates Chicago's quiet precipitation pattern could end later next week
 
Huge waves already roam the Pacific and 16-day computer rainfall estimates suggest storms, expected to batter the West Coast with increasing frequency could deposit totals of 8 or more inches of rain in sections of California, the majority of it to fall next week. Computer models continue to produce eye-catching jet stream-level wind speed forecasts for early next week.  The models suggest the El Nino-fortified jet expected to be roaring toward the southern West Coast at that time could boast rare 225 mph velocities at the 30,000 ft. jet airplane cruising altitude.

There's a relationship between the strength of high altitude winds and the storms which occur beneath them. Jet stream winds help produce the swift vertical motions which drop surface air pressures and lead to the flood of air which surges into vigorous storms. The stronger a jet stream's winds blow, the faster air ascends through the atmosphere. Low-level winds blowing into the storm must strengthen to compensate. Any storm which develops with a 200+ mph jet stream can be expected to produce especially strong winds and copious precipitation next week.

Already Tuesday, Pacific region forecasters were warning of possible 50 ft. breakers just off the shores of Hawaii in coming days and of 25 ft. swells along California coast--and this is days ahead of the most significant storminess expected to hit in a series of waves next week. The Navy's NOGAPS computer weather forecast model projects waves could approach five stories high in the Pacific just west of California next week, as the first surge of storminess related to the powerhouse 200+ mph upper winds surges toward North America's coast near California and Mexico's Baja California.


 
WX-FEATURE011310.jpg

What is Chicago's coldest high temperature?

|
Dear Tom,
What is Chicago's coldest high temperature?

Malcolm Vye
 
Dear Malcolm,
Two dates- Dec. 24, 1983 and Jan. 18, 1994 share the honor for the city's all-time lowest high temperature --a frigid 11 degrees below zero. A close runner-up is a high of minus 10 on Jan. 25, 1897.

Subzero high temperatures are rare events in Chicago, with only 45 on the books dating back to late 1870. Chicago climatologist Frank Wachowski tells us that all 45 of the subzero high occurrences are clustered in a 70-day period from Dec. 15 to Feb. 23, which encompasses the heart of the city's winter season.

Chicago's last encounter with subzero highs was last January 15 when the high topped out at 1 below zero. 

Chicago's lowest temperature on record is minus 27 on Jan. 20, 1985.

 
These shots of balls of ice along the Lake Michigan shoreline at Greenwood Beach are fascinating. They come to us from Steve Denenberg of Evanston who asks "what caused the ice to form this way?"

They form when small balls of snow develop and are blown into near freezing lake water where they can float and become coated with ice. When winds shift easterly, the balls of snow and ice are blown back onshore and pile up.  A similar phenomenon was reported by news services in Sweden in just the past week.
These are fascinating photos, Steve! THANKS for sharing them with us!
 
Tom Skilling
 
Lakefront4-11010.jpgLakefront2-11010.jpg


Photos courtesy Steve Denenberg, Evanston's Greenwood Beach


 


Graupel snow in Chicago Monday (1/11/2010)

|
Check out these pictures of graupel snow---the kernel-like grains of snow which occur when a snowflake falls through a warm layer and the outer branches of the snow crystals melt a bit while falling to earth.  This leads to the kernel of snow which is referred to by meteorologists as graupel. Many thanks to Brian Droege, the husband of the Executive Producer of our WGN 9PM News Diana Brodeur.  Brian took these photos on Chicago's northwest side Monday afternoon (1/11/2010).  Thanks Diana and Brian--GREAT shots!

--Tom Skilling

101210IMG_1979.jpg

011210IMG_1983.jpg
Photos courtesy of Brian Droege and Diana Brodeur, Chicago


Snowy scene in Westmont, Ill.

|
Alice Good sent us this snowy picture from Westmont, Ill. She tells us:

"Hey Tom...
I want you to know that my fiancee and I have a snowplow business here in the Chicago area,
"Snow Plus" Westmont IL and you are our guide to many a working night. Dave (owner) will not go to bed without your weather forecast. In fact, he often calls me if he knows I am by a TV to catch your noonday forecast as well.
"

Thanks for the great shot--and for watching!

101210DSC_0043.jpg
Photo courtesy of Alicia Good, Westmont, Ill.

First 32+ temps since Christmas ahead; 3 week cold spell easing

|
Arctic air's grip on Chicago's weather enters its 19th day Tuesday.  But far-reaching changes in critical upper level steering winds taking place on a continental scale are to undermine the frigid air's dominance. The break in arctic-level temperatures may span much of the coming two weeks. Not  until month's end may bitter winds of arctic origin return brutally cold air to the metro area.

Coming days will offer winter weary Chicago area residents a noticeable respite from the bitter air at the heart of January's 13.9-degrees average temperature to date--a reading more than 9-degrees below normal. But the "warming" predicted which is to include the city's first above freezing afternoon readings since Christmas (Dec. 25), may occur a bit more slowly than many might hope. The reason is simple. An uninterrupted cover of snow extending west 600 miles to the rolling plains of central Kansas and Nebraska, will reflect warming sunlight back to space as mild Pacific air surges into the Midwest. Were that snow not in place the incoming air mass would likely produce highs in the low and mid 50s here Wednesday and Thursday. Instead, Chicagoans will have to settle for mid and upper 30s. That's still quite an improvement over the 32-degree and lower readings which have dominated since Christmas Day--and more than enough to encourage some afternoon thawing.

The nearly three week period since cold air first arrived here has averaged more than 8-degrees colder than a comparable period a year ago and has boosted home heating an estimated 14 percent.  During that time, the city's seasonal snowfall has surged to 28.3 inches--nearly twice (191 percent) normal---yet behind the 36.6 inches on the books a year ago.
   
Cold spell gripping Florida one of longest on record
 
Cold air of record or near record proportions has dominated most of the U.S. east of the Rockies all this month---and nowhere more dramatically than Florida. Historically, the Sunshine State has seen colder winter outbreaks---but few if any have lasted as long. Tampa recorded a 51-degree high Monday--the 10th consecutive day which failed to reach 60-degrees. Never over the term of weather records there (extending back 1890) has there been a longer spell of sub-60-degree temperatures. Many sections of the state recorded record-breaking lows in the teens and 20s early Monday. Miami's 62-degree high followed 48 straight hours below 50-degree temperatures--one of the longest sub-50-degree spells since records began in 1839.


Signs El Nino-like pattern could begin pounding California with powerful storms by next week
 
Longer-range computer projections place jet stream winds approaching the California coast early next week at a rarely seen 225 mph. Powerhouse storms become a real threat when jet stream winds grow that strong. Computer estimates of potential California precipitation over the coming 16 days---much of it predicted to fall next week--exceed 8 inches. Windy, wet West Coast storms are a hallmark of El Nino cold seasons.
 
 


 
WX-FEATURE011209.jpg

Chicago's bitterly cold February 1981

|
Dear Tom,
I was at Navy boot camp at Great Lakes from January-March 1981 and remember it being unusually cold with a lot of snow. Can you help on the details?

Erik Miller Evanston
 
Dear Eric,
For the most part, the January to March 1981 period was "winter-as-usual" in Chicago, but your memories may have been influenced by a major snow storm that was followed by bitterly cold weather in February. Chicago was rocked by nearly a foot of snow on Feb. 10-11. Plunging temperatures in the wake of the storm brought back-to-back lows of minus 11 degrees, and  strong winds produced near blizzard conditions as blowing and drifting snow brought traffic to a standstill and created wind chills as low as 45 below zero. With the exception of that big storm the rest of the winter produced only minor amounts of snow.

 

Lake effect snow returns to Chicago and Northern Indiana

|

Up to 2 and 1/2 inches of snow fell over portions of the Chicago area Monday night.   For the very latest, follow the link below to the WGN Severe Weather Blog.  

http://weblogs.wgntv.com/chicago-weather/severe-weather/

Tim's Weather World: Lake Effect Snow 101

| | Comments (2)

Lake effect snow played a big part in last weeks snow storm.  Northern Indiana had the biggest snowfall amounts with some areas getting nearly a foot of snow.   There will be some light lake effect snow showers there tonight as well.

It could always be worse though.  Parts of western New York State get almost 200" of snow annually with most of that coming in the form of lake effect snow.

  Lakeeffectmailbox.jpgTo find out more about the science behind lake effect snow, check out this article from NOAA:

http://www.noaa.gov/features/02_monitoring/index.html

Check me out on twitter or facebook here-

www.facebook.com/TimMcGillWeatherGuy

http://twitter.com/WGNWeatherGuy

Light snow heralds a final arctic push

|
A long-awaited and much-anticipated end to Chicago's prolonged cold spell is at hand, but a final surge of arctic air must first be endured. It arrives this morning, accompanied by a dusting of snow and northwest winds gusting above 25 mph. Temperatures start upward on Tuesday, and readings are forecast to break above freezing (32 degrees) on Wednesday, ending an 18-day string of days at or below freezing.
 
Southeast in deep freeze
Just as in Chicago, the Southeast is struggling through a prolonged cold spell. Unlike Chicago, the southeastern chill is establishing new record-low nighttime and daytime temperatures. Miami, with temperature records dating back to 1839, has recorded only five days with high temperatures below 50 degrees. Sunday's high of 48 degrees was the sixth, and its Sunday morning low, 35 degrees, tied a long-standing record for the date. Snow flurries visited Orlando Sunday afternoon, and Tampa had rain and sleet on Saturday and again Sunday. Cold-sensitive vegetation continues to suffer both from the intensity of the chill and from its multiday duration.
-- By Richard Koeneman, WGN-TV Meteorologist
FEATURE01112010.jpg

Lake-effect snow elsewhere in the world

|
Dear Tom,
Is lake-effect snow unique to the Great Lakes or does it occur in other parts of the world?

George Smundin, Munster, Ind.

Dear George,
Geography has made the Great Lakes the world's epicenter for lake-effect snow because they lie directly in the path of bitterly cold arctic outbreaks. In addition, higher terrain in some locations downwind of the lakes (in Upper Michigan, for example) focus the snow, resulting in massive annual totals that exceed 250 inches.
However, lake-effect snow can occur anywhere in the world where cold air flows across a substantially large body of open water. That happens downwind of Great Salt Lake, Utah. Worldwide, some of the most significant lake-effect snows occur in Scandinavia off the Gulfs of Bothina and Finland, and in eastern Canada off of Hudson Bay and the Gulf of St. Lawrence.

Wintry central Wisconsin sunset

|
Thanks to John Kloch for passing along these sunset pictures taken in the central Wisconsin taken near Pittsville, Wisconsin. just west of Wisconsin Rapids.

setting sun 001 - Copy [640x480].jpg

setting sun 002 - Copy [640x480].jpg
Photos by John Kloch

Bitterly cold morning, Florida snow

|

Overnight lows fell well below zero across much of the Chicago area Saturday night and snow was spotted as far south as Miami on Saturday!   For the very latest, check out the WGN Severe Weather Blog

http://weblogs.wgntv.com/chicago-weather/severe-weather/

 

Icicle artistry

| | Comments (2)
Thanks to Ann Roos of Schaumburg for sharing these shots of icicles that have become  so common around the Chicago area in recent days.

IMG_1552 [640x480].JPG

IMG_1553 [640x480].JPG
Photos by Ann Roos

Chicago is poised to climb out of the deep freeze

|
Chicago has endured a prolonged cold spell and the city's temperatures have not been above freezing since the thermometer hit 43 degrees on Christmas Day. That was 16 days ago, and the city area has also had 14 to 20 inches of snow during that cold period. After widespread subzero readings early this morning in the coldest outlying locations, daytime temperatures, aided by abundant sunshine,  are set to recover rapidly to the middle and upper 20s in the afternoon. A short-lived but nonetheless potent reinforcing surge of Canadian air arrives early Monday, accompanied by a dusting of snow.
 
Cold pattern breaks; warmer days ahead

All cold things must come to an end, and computer models of the atmosphere indicate Chicago's lengthy cold spell has just about run its course. A relatively mild flow of Pacific air is heading this way and should arrive Wednesday. The city's string of days with temperatures at or below freezing will end at 18 on Tuesday as readings on Wednesday surge well into the 30s. And that's the start of a new pattern of "mild" days.

 

Ice Station Chicago: 11 days in the deep freeze January 1982

|
WX-FEATURE011010.jpg

What is the farthest south "polar expresses" have driven?

|
Dear Tom
What is the farthest south "polar expresses" have driven?

-Vic Mazylewski, Shorewood

Dear Vic,
Arctic outbreaks routinely penetrate into the Deep South and a few will sweep through Florida and Texas. However, some cold surges have reached Central America and the northern portion of South America. Topography plays a limiting role, with Central American mountain ranges halting the southern push of cold air. Some of the natural barriers include the Sierra Madre range and the Costa Rican mountains south of Lake Nicaragua. Afew vigorous cold outbreaks have made it to about 7 or 8 degrees north latitude where they were finally halted by the mountains of Colombia. At those low latitudes, the cold air is very shallow and greatly modified, and only lowers the temperature a few degrees.  

Cold and snowy, but not THAT cold and snowy

| | Comments (2)
We don't need to be told that we've been contending with a cold and snowy winter, but a review of Chicago's weather records reveals that it's been much worse on many occasions in the past. Through Jan. 8, this winter's average temperature, 23.9 degrees, ranks merely 28th coldest  since 1870-71, 27 winters have been colder in the Dec. 1-Jan. 8 period; the coldest: 16.4 degrees in 1983-84. Seasonal snowfall through Jan. 8 stands at 28.3 inches  sufficient to generate complaints from snow-weary residents, but only 8th snowiest. The greatest: 52.4 in 1951-52.
 
Lake snow smothers north Indiana
Lake-effect snows have been daily occurrences since Dec. 26 in the snow belt regions of northern Indiana. Snow totals there are impressive, even by the snowy standards of those areas. South Bend, Ind., recorded 23 inches during the first week of 2010, second only to the 27.3-inch total that fell during Jan. 1-7, 1999. Unofficial accumulations of 30-40 inches in the Dec. 26-Jan. 7 period have been reported in northern Indiana locations within 15 miles of Lake Michigan.
-- By Richard Koeneman, WGN-TV Meteorologist
FEATURE01092010.jpg

Colder than normal winter during El Nino

| | Comments (2)
Dear Tom,
Is it possible to have a winter with temperatures averaging below normal despite El Nino?

Ted Karamanski
Dear Ted,
It is possible. We're less than halfway through the current winter and so the jury is still out, but the winter thus far has been running considerably colder and snowier than normal. El Ninos (above-average water temperatures in the tropical Pacific Ocean) have occurred 17 times since 1950 and an 18th began in July 2009. It continues at present. El Ninos persist a year or two, with worldwide weather consequences.
On balance, Chicago's "El Nino winters" tend to be mild and tranquil, but that means only that significantly harsh winter weather conditions, although they still occur, visit the city less frequently than usual and with lessened duration. On average, about 60 percent of Chicago's El Nino winters deliver above-normal temperatures and below-normal snowfall.

Post-snowstorm sunset

|
Jeremy and Sarah of Lake in the Hills sent us this beautiful picture of sunset after our recent snowstorm. Thank you both for the great photo!

20100108sunset01.jpg

A wintry wonderland in Crown Point, Indiana

| | Comments (1)
Thanks to Roxanne Myers for passing along these wintry shots taken at Bass Lake at Lake of the Four Seasons in Crown Point, Indiana.

P1010158 [640x480].jpg

P1010150 [640x480].jpg

P1010162 [640x480].jpg

P1010151 [640x480].jpg
Photos by Roxanne Myers

New snowfall record for Chicago

|

For the very latest on the winter storm, follow the link below and check out the WGN Severe Weather Blog

 

http://weblogs.wgntv.com/chicago-weather/severe-weather/

 

 

Lake effect snow bring huge flakes to Gurnee

|
Thanks to former WGN Weather Intern Patrick Korellis for passing along these pictures of giant snowflakes that were falling as lake effect snow was moving into the Gurnee area late Thursday evening.

DSCF0006 [640x480].JPG

DSCF0009 [640x480].JPG

DSCF0005 [640x480].JPG
Photos by Patrick Korellis
Lake-effect snow falling at the rate of 1-2 inches per hour in southern Wisconsin Thursday evening was spreading south toward metropolitan Chicago. That promises to deliver several inches of additional snow on top of the 3-6 inches that had already blanketed the area Thursday evening. Morning commuters will have to contend with that.   
 
Mild "El Nino winter" still possible


An El Nino event (abnormally warm ocean water in the equatorial Pacific Ocean westward from South America) is in progress and Chicago's "El Nino winters" are usually milder than normal. That's not been the case so far, of course, because winter readings  thus far place December and early January temperatures among the city's colder 30 percent during that period. However, computer models suggest a major weather pattern change is likely to begin in 4-6 days. It's speculative at this point, but this might finally signal a break in the persistent pattern of sub-normal winter temperatures.  
WX-FEATURE010810.jpg

Dear Tom,
You once set the record straight that Chicago never had a month-long below-zero streak. However, didn't we have a string of below-freezing days that lasted more than a month?

Mel Theobald, Chicago

Dear Mel,

Chicago's temperature hit 37 degrees on Dec. 27, 1976, and then arctic air swept across the city and temperatures plunged. Little did Chicagoans realize on that December day that the city's longest period of continuously sub-freezing temperatures had begun. A record 43 days would pass before the temperature again climbed to freezing (32 degrees). The 43-day period from Dec. 28, 1976, through Feb. 8, 1977, stands as Chicago's longest string of consecutively sub-freezing days. Included within that period were 22 days with minimum temperatures at or below zero, and the worst day of all: Jan. 16, 1977, with frigid high/low readings of -7/-19 degrees.

Tough sledding in an unusually snow England

| | Comments (6)
Thanks to Sam Boateng for passing along these shots from a town west of London called Reading. Sam reports 21 inches of snow there so far this winter putting them on a par with the Chicago area. After the latest  storm brought a foot of snow, the mercury dropped to 4 degrees.
Sam reports that many people are snowed in and that trees are collapsing from the weight of the heavy, wet snow. The area seldom gets snow and there are virtually no snow shovels or plows available to remove it. Sam lived in Chicago for more than 9 years so he is quite familiar with wintry weather.

Still snowed in [640x480].jpg 

A local igloo [640x480].jpg

Our balcony [640x480].jpg

View outside our apartment [640x480].jpg
Photos by Sam Boateng

This storm has it all

|
Before it's over and quiet weather returns, Chicagoans will have sampled the full range of the atmosphere's winter weather arsenal: storm duration (it's to be a 3-day event: Thursday-Friday snow, Saturday cold), significant snow totals, additional lake-effect snow, blowing and drifting, poor visibility, treacherous highway conditions, low temperatures, biting winds and subzero wind-chill readings. We've experienced far worse, of course, but that's little consolation to those who will be contending with the weather in upcoming days.
 
And the chill has penetrated into the Deep South. Jacksonville, Florida, registered  21 degrees early Wednesday, tying a record from 1884; Tampa hit 27 degrees, establishing a new record for the date.
 
Chicago's 10-inch snowstorms

Chicago weather historian Frank Wachowski informs us that the city's winter-weather climatology (spanning 125 snow seasons from 1884-85 through 2008-09) includes 43 storms that produced at least 10 inches of snow - on average, one such storm every three years.
 
 
 

Chicago in for a windy, lake-enhanced snowstorm

|
WX-FEATURE010710.jpg


What does a 30 percent chance of precipitation mean?

| | Comments (3)
Dear Tom,
Exactly what does a 30 percent chance of precipitation mean?

Chris Barajas, Chicago

Dear Chris,

We hear this question frequently, so let's re-visit the issue. Regardless of its accuracy, a weather forecast fails if the user does not understand the forecaster's words.

The proper interpretation of a 30 percent chance of snow (or other precipitation), assuming the forecast verifies perfectly, is that you will have snow on your head three out of ten times that you hear such a forecast.

The forecaster may believe snow will cover 100 percent of the area if it arrives, but his confidence that it will arrive is only 30 percent. Alternatively, the forecaster might have great confidence that snow will occur, but he believes it will consist of scattered snow showers affecting only 30 percent of the area.

Regardless of the forecaster's rationale, the meaning for you is always the same: The chance of snow on your head is 30 percent.

The weather just won't give us a break. It's been cold for several days, and with an average temperature of 11.0 degrees, it's Chicago's 17th coldest Jan. 1-5 in 140 years. The persistent chill has set the stage for  a snowstorm that promises to become the season's biggest to date. Snow arrives here this evening and continues overnight, finally diminishing to flurries by Friday morning. The snow, falling in an especially cold environment, is likely to be "fluffy," with considerably less water content that usual. And as an added kicker, moisture from Lake Michigan may add 2-5 inches to local accumulations.
 
Major snowstorm in Seoul, South Korea

A sudden winter storm on January 4 blanketed portions of the Korean Peninsula with record snows. Seoul received 11-12 inches, the city's greatest single-day snowfall since Korea began conducting meteorological surveys in 1937.  Beijing, China, received 3 inches in the same storm and that was its greatest one-day total in 59 years.
 

Cold, snowy weather situation as storm sweeps through

|
WX-FEATURE010610.jpg


Dear Tom,
How far inland has lake-effect snow caused by Lake Michigan ever reached?

Douglas Hanbury, East Peoria
 
Dear Douglas,

Lake-effect snows typically fall within about 50 miles of Lake Michigan's southern shore when frigid arctic air sweeps southeastward across the lake. The heaviest snows usually target areas within about 20 miles of the lake in the snowbelts of north-central Indiana and southwest Lower Michigan.

However, satellite photographs show that plumes of clouds and flurries, often originating over Lake Superior and then strengthening as they pick up additional moisture in passage over Lake Michigan, generate clouds and snow as far away as the Appalachian highlands of northern Georgia. Weaker northeast-wind situations sometimes produce lake snows, but those snows they seldom make it beyond Peoria.
 

 

Cold, then snow, then colder

|
No relief is in sight for area residents growing weary of the extended cold spell. Temperatures are set to remain cold into mid-week, and then a new storm is likely to blanket the city with a half-foot of fluffy, low-water-content snow late Wednesday through Thursday. But that's not the end: Another strong surge of arctic air follows the snow and temperatures dive. 
 
 
Even Florida is freezing

It is not unheard of for Florida - even south Florida -- to experience brief periods of freezing or near-freezing temperatures each winter. Even coastal areas and coastal cities like Miami average a light frost every five years or so. Typically, though, the cold snaps rarely last beyond two days. What is noteworthy about the current cold spell is the duration of the event. Florida is likely to experience much below-normal temperatures and nighttime freezes and frosts for a period of seven days before the weather breaks. The Miami  National Weather Service advises that will be the state's longest cold stretch in 15 to 25 years.
 

 
WX-FEATURE010509.jpg

Dear Tom,
Does Chicago ever get a major lake-effect snow like they do in Michigan and Indiana?

Michael Nejedly
 
Dear Michael,
Arctic air usually arrives in the Midwest on northwest winds that direct the bulk of the Lake Michigan generated snowfall to Michigan and northwest Indiana. Chicago seldom receives a major dose of pure lake-effect snow, but it has lake-enhanced snow from a northeast flow as low pressure systems pass to the south of the city.

Weather historian Frank Wachowski reports that one of the city's biggest lake-effect snow events was on Dec. 19, 1973 when 5-12 inches fell in the city while amounts up to two feet socked areas along the west shore of the lake from Lake County, Ill. to Green Bay.
 

Tim's Weather World: Winter & Nighttime Tornadoes

| | Comments (1)

Today marks the 10th day in a row with at or below average temperatures.  During the last ten days, 9 of them have been below average with one right at average.  It looks like this streak will continue through the weekend with only minor moderation now and then.  It might seem like a strange time to talk about tornadoes but that's not what NOAA thinks.

tornado112907.jpgNOAA's Storm Prediction Center has announced they will now issue new public service outlooks whenever conditions are favorable for strong to violent tornadoes to occur overnight.  This being an El Nino winter, the chances have increased for tornadoes to occur in the deep south over Florida and the Gulf Coast region.  Last February's "Super Tuesday" outbreak that killed 57 people in Kansas, Tennessee, Kentucky and Alabama indicated people tend to minimize the threat of tornadoes during the winter.  The SPC wants to change that and these new outlooks should help.  To find out more about this, check out this link

http://www.noaanews.noaa.gov/stories2009/20091214_tornado.html

Check me out on twitter and Facebook here

www.facebook.com/TimMcGillWeatherGuy

http://twitter.com/WGNWeatherGuy

Deep chill to persist through week

|
The cold has been relentless since the day after Christmas and it's likely to continue for another week. In the short run, we'll experience incrementally higher temperatures through mid week before another reinforcing surge of arctic air  accompanied by a few inches of snow  arrives early Thursday and extends the life of the cold spell through the weekend.
 
A string of nine consecutive days with maximum temperatures no higher than 25 degrees  will have been tallied by Jan. 9, but that won't challenge the record: We experienced 17 consecutive days at or below 25 degrees from Dec. 16, 1983, through Jan. 1, 1984.
 
Lake-effect snow piles up
Cold air blowing across Lake Michigan has been depositing impressive snows in the snow belt areas of north-central Indiana and southwest Lower Michigan. Local 28-inch totals had accumulated in Michigan's Berrien County by Sunday evening, and heavy snow was continuing. Totals approaching four feet are possible by midweek.
-- By Richard Koeneman, WGN-TV Meteorologist
FEATURE01042010.jpg

When Chicago's coldest weather occurred

| | Comments (4)
Dear Tom,
I recall temperatures in Chicago in the 1980s on the order of 20 below zero, the likes of which we haven't seen since. When was the last time it hit 20 below zero here?

Robert Fox, Chicago
Dear Robert,
Chicago has registered 20 degrees below zero or lower on 15 occasions since the inception of records on Nov. 1, 1870. Our most recent occurrence was 16 years ago: 21 below on Jan. 18, 1994. However, your memory of intense cold in the 1980s is correct because nine of Chicago's 15 occurrences of 20 degrees below zero or lower occurred in the four-year period, 1982-1985. It was a remarkable and utterly unprecedented clustering of bitterly cold readings, and it included Chicago's all-time low temperature, 27 below zero on Jan. 20, 1985. Five other "minus 20 days" occurred here in the late 1800s, the last being 21 below on Feb. 9, 1899, and then a span of 83 years elapsed until the next one: 26 below on Jan. 10, 1982.

Coldest morning of the 2009-2010 winter in many areas

| | Comments (2)

Much of Chicago woke up to what is now officially the coldest morning of this winter season when the temperature dropped to 1 degree below zero (-1) at O'Hare Airport shortly before 7 o'clock this morning.  Prior to today, the coldest reading at Chicago's official reporting station was zero, which occurred on December 8, 2009.

For more on this weekend's cold snap, as well as the latest snowfall totals from Indiana and Michigan, follow the link below to the WGN Severe Weather Blog

http://weblogs.wgntv.com/chicago-weather/severe-weather/

 

With a steady supply of arctic air sweeping across Lake Michigan, the lake-effect snow machine has been running at high speed dumping heavy snow across portions of western Lower Michigan and north-central Indiana. Amounts up to 2 feet have fallen since New Year's Eve and the onslaught of flakes continues.Thanks to David Lastrucci of Mt. Prospect who has been witnessing his first real lake-effect snow event while taking visiting family from Italy on a tour of the area. These picture were taken in Saugatuck and Douglas. In David's own words..." What a snow!! Mother Nature is AMAZING!!"

P1010851.JPG [640x480].jpg

P1010844.JPG [640x480].jpg

P1010852.JPG [640x480].jpg

P1010848.JPG [640x480].jpg

P1010859.JPG [640x480].jpg
Photos by David Lastrucci

Deep chill persists but snow is 50 miles east

|
The cold spell that we are experiencing is noteworthy not for the intensity of its chill - we've experienced much worse -- but for its persistence. Ten 10 days will  pass before significantly higher temperatures arrive. And Saturday was perihelion day, the day on which the Earth makes its closest approach to the sun in its annual orbit about the sun. 
 
We're not alone in our cold-weather discomfort. Very cold air holds all of the nation east of the Rocky mountains in its frigid grip -- fully two-thirds of the Lower 48.
 
Surges of lake-effect snow swirling off Lake Michigan continue to cause problems for residents of the snow-belt areas of northern Indiana and southwest Lower Michigan, but they take that in stride even as local accumulations exceed 20 inches by Sunday night.
 
The chill plows south
 
Residents of the Deep South, however, are less accustomed to harsh winter conditions. Sub-freezing temperatures are pushing into northern Florida. Even Cuba is experiencing unseasonable chill.

 

2009-10 seasonal snow total to date ranks among 15 snowiest

|
WX-FEATURE010310.jpg
Dear Tom,
Have the levees around New Orleans been repaired since Hurricane Katrina? Is New Orleans now protected from future hurricane flooding?

--Richard Waller, Chicago

Dear Richard,

A major hurricane has not struck New Orleans since the Katrina disaster in August 2005, but Lt. Gen. Robert Van Antwerp, Chief of the Army Corps of Engineers, gives a mixed review. More than $14 billion is being spent to repair and build levees and other flood control structures in the New Orleans area, and work is under way. In October Van Antwerp said, "Protect the city, no; reduce the risk, yes. ... We can develop better early warning systems, better evacuation plans, better levees to hold back most of the water, but we cannot stop levees being overtopped and the city (being) flooded."

New Year's Eve full moon

| | Comments (1)
The second full moon of December illuminated the skies over Chicago on a cold New Year's Eve. The next time there will be a  New Year's Eve full moon will be in 2028. The last such occurrence was in 1990. Thanks to Katie Reeves  of Huntley Illinois for passing along this geat shot.

DSC_0076 [640x480].JPG
Photo by Katie Reeves

Arctic cold a good bet for next 7 days in Chicago

|
The atmospheric flow pattern at high as well as low levels aloft will take an almost direct path from the coldest regions of the Arctic south through the Canadian Provinces of Manitoba and Ontario into the western Great Lakes and Midwest. Even though the air will pass over snow-covered soils almost the entire route, it will modify somewhat with time. Saturday's forecast high of 9 degrees will be the coldest high temperature in Chicago since a 3-degree high observed almost a year ago Jan. 16. Chicago's daytime highs should be nearly 20 degrees below average this weekend and some 10 to 15 degrees below average next week. During this period, wind chill values will consistently run from the single digits to subzero.
 
Snow confined mainly to the Snowbelt

With a persistent northwest wind flowing over the Lake Michigan waters, almost continuous snow will fall along and inland of the northwest Indiana and western Lower Michigan shoreline. While snowfall totals in the snowbelt could range from one to three feet in the next seven days, current forecasts have a significant chance at snow for Chicago and northeast Illinois occurring only with the passage of low pressure to the south later Wednesday and Thursday.
FEATURE01022010.jpg

Bad weather and cold fronts

|
Dear Tom,
Why does most bad weather occur along a cold front?
Kathy Kastanes


Dear Kathy,
A cold front, so named because it is the leading edge (the "front") of an advancing mass of relatively cold air, is indeed the source of much of Chicago's "bad weather." This is so because clouds and precipitation invariably occur in an environment of rising air, and cold frontal zones provide such an environment.

In a typical cold frontal situation, cold air (because it is more dense than warmer air) hugs the surface as it advances, sliding under and lifting the milder air that it is replacing. If the lifting process and moisture are sufficient (and they usually are), clouds and precipitation develop. In addition, the wind field in a frontal zone (post-frontal northwest winds impinging on pre-frontal southwest winds) forces air upward in the frontal zone.

WGN Weather on Twitter