tag:weblogs.wgntv.com,2009-04-10:/chicago-weather/tom-skilling-blog//349 2009-11-20T04:42:36Z WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area. Movable Type 4.1 tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146565 2009-11-20T04:41:27Z 2009-11-20T04:42:36Z

Friday marks the 17th consecutive day of milder than normal temperatures in Chicago--one of the five longest such spells on record in the month of November at Midway Airport. Weather observations there date back to 1928. With above normal readings...

wgnweather

A stubborn low pressure responsible for five consecutive days of cloudy skies has lifted out of the area--but, moisture lingers in its wake. And, while clouds may break for passing sun in coming days, spells of overcast skies aren't likely to exit the area completely--fitting in a month which is historically the second cloudiest of the year (December is the cloudiest).


Daytime temperatures are predicted to rise several degrees in each of the next three days. But, indications of change in the weeks ahead abound. Two key cold weather indexes, which look at cold air availability in the arctic as well as the predicted buckling of the jet stream over the North Atlantic---a development which frequently ends up sending cold air spilling southward over the eastern U.S., including the Midwest---have turned negative. It's an indication of colder weather on the way. The chill appears likely to hit in bursts---the first to produce a rain-generating disturbance here late Monday into Tuesday. That push of cold air is to last through through Thanksgiving (next Thursday) and may deliver this area's coldest readings of the season to date. There are growing indications flurries or snow showers could sweep at least parts of the metro area Wednesday and Thursday. Still colder air appears a threat as December hits 12 days from now. That chilly spell could allow some sticking snow at some point in December's opening 5-days, according to several preliminary computer forecast scenarios.
 
West Coast hit by driving rains, huge mountain snows, 100 mph wind gusts
 
The storm pounding the West Coast Thursday has prompted warnings for all manner of extreme weather---from heavy rain and flooding, to mountain snows measured in feet, and high winds responsible for huge waves lashing the coastline. Gusts hit 103 mph at Rogue Valley International Airport near in southern Oregon near Medford Thursday.
 
]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146564 2009-11-20T04:39:09Z 2009-11-20T04:40:37Z

wgnweather

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146563 2009-11-20T04:27:07Z 2009-11-20T04:29:49Z

wgnweather Dear Tom,
I was married on Dec. 8, 1945 and it was a very warm day. A week later when my friend got married on Dec. 15 it was below zero. Can you provide the details?
Delores Faltynek Antioch
 
Dear Delores,
We asked climatologist Frank Wachowski to check the weather archives and he found your recollections to be right on---illustrating how quickly Chicago weather can change this time of the year. You wedding day was indeed very mild with a balmy high of 53 degrees. Your friend was not as fortunate as winter hit with a vengeance in the following week. A cold front dropped temperatures into the 20s and a major snowstorm followed on Dec.13 and 14 bringing about 4 inches of snow. Your friend's Dec. 15 wedding took place on a very wintry day with a high of just 11, a low of 2 below zero and 4 inches of snow on the ground.

 ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146542 2009-11-19T04:38:13Z 2009-11-19T04:39:13Z

Clouds cover area skies a 5th consecutive day Thursday and periods of rain are to continue. Wednesday's 0.17 inches at O'Hare made it the wettest day since late October. The day's 47-degree peak reading was the third consecutive day in...

wgnweather
To say it's been dreary is a bit of an understatement. Chicagoans have seen only 1 percent of the area's possible sun since Sunday---and November, typically the second-cloudiest month of the year here, is showing every sign of living up to its cloudy reputation over the coming week. The sluggish storm which has spun in place all week shrouding the area under a veil of clouds, is finally to lift out of the Midwest Friday. But computer models hold a fair amount of moisture in the lowest 5,000 feet of the atmosphere in the wake of the departing storm. This is more than adequate to produce clouds and could make sunshine a comparatively rare commodity.  What's more, suggestions that a wet new storm is to come together across the Midwest Monday is hardly a boon to those in search of sun. Though the details of its development aren't yet carved in stone, a number of forecast scenarios predict  strengthening over eastern Iowa and Missouri Monday, leading to the onset of chilly rains in Chicago Monday night and Tuesday.

Temperatures over much of the coming two weeks remain above seasonal norms, but display a downward glide. One lobe of chilly air is likely to be drawn into the Midwest on the blustery backside of next week's storm, producing a cool Wednesday and Thanksgiving Day. It's possible mid-week cooling will be sufficient to introduce snow or rain showers. But even colder air may loom beyond that. Though temperatures are likely to moderate after Thanksgiving (next Thursday,) preliminary indications suggest December---which is just 13 days away--may open on a wintry note as even colder air descends into the Chicago area. 
 
Historic odds of a trace or more of snow falling in November's 12 remaining days: 88 percent
 
The possibility of snow grows this time of year. Snowfall records in Chicago extend back 125 years to 1884.  At a least a trace of snow has fallen in 88 percent of those years between now and the start of December. Measurable snow (0.1 inches or more) has fallen in the same period in 60 percent of years and an inch of snow has fallen by December first 38 percent of the time.
 ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146541 2009-11-19T04:13:28Z 2009-11-19T04:15:19Z

wgnweather

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146540 2009-11-19T04:09:17Z 2009-11-19T04:11:05Z

wgnweather Dear Tom,
I am putting in a bid for sidewalk snow removal in the Lincoln-Belmont-Ashland shopping area. Can you provide the average frequency of the number of snows per season of various amounts?
Bill Haderlein, Chicagoland Deck Cleaning & Sealing

Dear Bill,
Indeed we can. The following statistics are derived from 80 years (1929-2008) of Midway Airport snowfall data, courtesy of Chicago weather historian Frank Wachowski.

On average, Chicago receives at least one-half inch of snow 17 times per snow season. Snow storms in the range of 1-3 inches occur about 7 times; 4-6 inches, twice; 7-10 inches, once; more than 10 inches, about once every other year.

A note of caution: The number of storms that might occur in any given snow season varies greatly from year to year. The extreme winter of 1978-79 put down 10 snows in excess of 4 inches and a season total of 89.7 inches. ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146538 2009-11-18T23:17:56Z 2009-11-18T23:21:32Z

Joan Knight sent us this a gorgeous sunset picture taken in Lombard this past Friday the Nov. 13th. Wow, what a great shot!Thanks Joan!Photo courtesy of Joan Knight, Lombard, Illinois...

wgnweather
Thanks Joan!


Photo courtesy of Joan Knight, Lombard, Illinois

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146537 2009-11-18T23:07:09Z 2009-11-18T23:12:09Z

Check this out! David Leonard sends us these shots of a rain gauge produced by his 2nd grade son Kyle as part of his science curriculum. Kyle's teacher is Mrs. Durkin of Willow Creek School in Woodridge, Illinois and provided...

wgnweather Check this out! David Leonard sends us these shots of a rain gauge produced by his 2nd grade son Kyle as part of his science curriculum. Kyle's teacher is Mrs. Durkin of Willow Creek School in Woodridge, Illinois and provided him the instructions on how to make the
instrument. Leonard writes:

" It was pretty cool to see how a seven year old went about the process of creating this rain gauge. The pop bottle cut off at the top and inverted to serve as a rain collector, water was filled to a certain level to compensate for the different shape at the bottom and the placement of the ruler at the water level. His measurement of the rain received last night was approx. 0.5 cm."

Very cool indeed--and congratulations Kyle on a job well done!

Tom Skilling





Photos courtesy of David Leonard, Woodridge, Illinois

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146529 2009-11-18T05:01:27Z 2009-11-18T05:02:40Z

Chicago's weather has turned wet for the first time in over two weeks bringing to an end the driest November open in a decade. Just 0.01 inches had fallen in the city up to the time rains arrived Tuesday afternoon....

Tom Skilling Chicago's weather has turned wet for the first time in over two weeks bringing to an end the driest November open in a decade. Just 0.01 inches had fallen in the city up to the time rains arrived Tuesday afternoon. Rainfall is predicted to continue in waves through Thursday totaling 0.40 to 1 inches making it the area's heaviest spell of precipitation in the 18 days since 0.81 inches fell October 30.


Northeast winds, so successful in halting the northward spread of rain Monday, proved no match for the deep-layered surge of moist air which pushed rain into the metro area by Tuesday afternoon. The most impressive area totals ranged from 0.91 inches at Rensselaer and 0.71 inches at Hebron, both in northwest Indiana---to 0.61 in De Kalb County's Sandwich. Chicago rains, while enough to wet the pavement, weren't nearly as impressive---totaling just 0.08 inches at Midway and 0.05 at O'Hare---but more was expected to fall overnight.

The stalled low pressure system responsible for the wet weather is a "cut-off low." The term originates from the fact the strongest upper levels winds, which might otherwise push such a disturbance along, become situated well to the north. Systems spin in place when this happens, unable to move very quickly.  The varied barometric pressures on the storm's north side were behind Tuesday's howling northeast wind gusts which approached 40 mph here and limited wind chills to the low and mid 30s. 

Areas downstate bore the brunt of storm's rainfall for a second consecutive day. Totals there were impressive. Westville in east-central Illinois' Vermillion County just east of Champaign recorded 3.23 inches of rain while Lincoln was soaked by 3.14 and Danville was hit by 2.45.  To put those amounts in perspective, the entire month of November in Chicago typically sees 3.01 inches.
 

Alaska in the Deep Freeze; Interior temps drop under -40 degrees
 
Cold air has reached brutal proportions in the northernmost reaches of North America.  Temperatures in Alaska dropped to -45 degrees at Tanana--in the state's Interior not far from Fairbanks Tuesday, to -44 degrees at Bettles. Open water in southern Alaska appeared to "steam" as the bitterly cold air turned water vapor immediately to ice crystals, much as happens when brutally cold air makes contact with the "warmer" water of Lake Michigan here in winter. Days continue to shorten in across the northern hemisphere assuring cold air production is just beginning in the arctic. The sun sets in Barrow, Alaska Thursday for 64 days---not to rise again until late January.

Even where the sun is still visible during the day well to Chicago's north, it sits low in the sky. At its highest point Tuesday, the disc of the sun was just 6.1 degrees above the horizon in Fairbanks compared to 29 degrees above the horizon at its peak here in Chicago. (Note: Were the sun 90 degrees above the horizon, it would be directly overhead while a sun angle of 0 degrees means the sun's disc sits below the horizon.)


 
 



 ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146526 2009-11-18T04:00:42Z 2009-11-18T04:13:00Z

wgnweather

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146525 2009-11-18T03:48:46Z 2009-11-18T03:49:52Z

wgnweather Dear Tom,
What are the extremes for Chicago's average annual temperatures? Any sign the average is rising due to global warming?
Robert Roschke,  Chicago

Dear Robert,

In 138 years of official data, Chicago's average annual temperatures have ranged from 45.3 degrees (1875) to 54.5 degrees (1921). The trend of temperatures has been upward, but it's difficult to draw conclusions because the observation site has been relocated several times and each move disrupted the climatological continuity of the temperature record.

However, 80 years of data (1929-2008) from a single location -- Midway Airport -- indicate a warming trend, probably due more to a strengthening urban heat island effect than to global warming. Annual temperatures rose from 50.6 degrees during the first half of the period (1929-1968) to 51.2 degrees during the second half (1969-2008).

 ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146505 2009-11-17T04:47:56Z 2009-11-17T04:56:45Z

Tom Skilling
The wet storm, spinning in place over Missouri late Monday, is mired in an atmospheric blocking pattern which has the system, for all intents and purposes, spinning in place. Since any forward motion isn't expected to resume until late this week, it's likely the storm's impact on Chicago's weather has days to run. Computer models suggest the dry air riding Monday's northeast winds into the area is to moisten slowly allowing  rain prospects to rise. Once the atmosphere becomes saturated later Tuesday and Tuesday night, the rainfall which results could linger through Thursday.

While the air is to take on an increasingly damp, raw feel, temperatures are actually running above November averages. Winds and clouds are interfering with normal nocturnal (nighttime) cooling, a development which contributes to daily temperature surpluses. Tuesday marks the 14th consecutive of above normal November temperatures---and each day over the coming 7 days appears likely to finish ABOVE normal as well.
 
Changes loom Thanksgiving week; signs of colder temps and more storminess
 
Important atmospheric changes appear to loom next week. A dome of milder than normal air is predicted to take shape over eastern Canada and the Davis Strait between Labrador and Greenland. Such a development often signals a surge of cool air into eastern North America as the continent's jet streams begin buckling.  Ridging in the jet over the western Atlantic is offset by troughing in the eastern U.S. which produces northwest steering winds above the Midwest--a flow able to tap cold air at higher latitudes and tug it south. Two storm systems may be by-products of this pattern evolution and an analysis of temperatures suggests readings by the end of next week and the following weekend may dip 15 to 20-degrees below the levels predicted later this week.

Such a pattern change isn't out of line with typical late November developments.  125 years of snow records here reveals the week leading up to Thanksgiving has produced at least a trace of snow 74 percent of the time while measurable snow (0.1 inches or more) has fallen in 42 percent of all years since 1885.


 ]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146504 2009-11-17T04:26:54Z 2009-11-17T04:28:09Z

wgnweather

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146503 2009-11-17T04:24:56Z 2009-11-17T04:26:09Z

wgnweather

]]> tag:weblogs.wgntv.com,2009:/chicago-weather/tom-skilling-blog//349.146501 2009-11-17T04:07:20Z 2009-11-17T04:09:17Z

wgnweather

]]>