January 2008 Archives

As of 6:21 p.m. parts of our western suburbs have had as much as 4.5 inches of snow. The snow will continue for many more hours with the height of the storm expected during the morning rush hours. This could be the biggest snowstorm that we've seen this winter.

Tune in early to WGN-TV. Our morning news will have the latest weather and school closings as early as 4:30 a.m.

Chicago's largest day-to-next temperature changes
In the period Nov. 1, 1870, through Jan. 30, 2008

temperature rises
58º from 0º to 58º February 13-14, 1887
58º from 15º to 73º March 10-11, 1972
57º from 24º to 81º March 31-April 1, 2003

temperature falls
61º from 74º to 13º November 11-12, 1911
58º from 62º to 4º February 8-9, 1900
58º from 49º to -9º December 13-14, 1901

--By Tom Skilling, WGN-TV Chief Meteorologist

Arctic air: A type of air mass whose characteristics are developed in the cold season over ice- and snow-covered areas of the far north. It has low temperatures, low moisture content, and is very stable. Air masses of arctic origin cover Chicago about six percent of the time.

Arctic outbreak: The rapid movement of a mass of air originating above the Arctic Circle southward to the Gulf of Mexico, or farther. Arctic outbreaks bring Chicago its lowest autumn and winter temperatures; also called "polar outbreak."

Cold wave: In popular usage, a period of very cold weather. Meteorologically, a rapid fall in temperature within 24 hours to temperatures requiring substantially increased protection to agriculture, industry, commerce and social activities.

Norther: In popular usage in the southern United States, especially Texas, a strong cold wind from the northwest, north or northeast. It is the cold outbreak associated with the southward movement of a frigid air mass.

Blue norther: In popular usage in the Southern Great Plains, a blast of bitterly cold arctic air that surges south across Texas during the winter, bringing strong north winds and a sudden, sharp temperature drop.

--By Paul Dailey, WGN Weather Center Meteorologist

--By Tom Skilling, WGN-TV Chief Meteorologist

Photos courtesy of Anson Mount—thanks for sharing these pictures with us!
--The WGN-TV Weather Center

Chicago snow facts
(based on 123 years of snow statistics beginning with the winter of 1884-85)

8.2 inches

On average, that is the largest snowstorm that Chicago can expect in any given winter season.

In Chicago, the winter's biggest snowstorm has ranged from a puny 2.4 inches during the 1921-22 snow season to 23.0 inches in 1966-67.

Walter Swiston, official observer for the FAA and the National Weather Service at O’Hare International Airport, shares this amazing winter mammatus cloud photo with us. Mammatus are best known to occur on the underside of thunderstorm anvils. But, the flood of milder air up and over the retreating arctic chill produced the clouds pictured above. Thanks Walter!
--By Tom Skilling, WGN-TV Chief Meteorologist

--By Tom Skilling, WGN-TV Chief Meteorologist

Cryosphere: The portions of the Earth (in the atmosphere, at the surface, in the ground) in which water is in solid form. It includes snow and ice crystals in the air, snow cover and ice caps, floating ice (on rivers, lakes, oceans), glaciers, permafrost, etc. The word is derived from the Greek "kyros," meaning frost or icy cold.

Intergelisol: A sub-surface layer of frozen ground that might persist for a few years but is not permanently frozen ground and is not considered to be permafrost (soil and rock whose temperature is permanently at or below 32 degrees).

Mollisol: In regions of permanently frozen underlying soil, mollisol is the surface layer that freezes in the winter and thaws in the summer. It varies in thickness from a few inches to several feet.

Pereletok: A sub-surface layer of frozen ground that might persist for a few years, but is not permanently frozen and is not considered to be permafrost. The term is Russian, meaning "survives over the summer."

Permafrost: Permanently frozen ground; it underlies about 85 percent of the state of Alaska, and in northern Alaska it reaches its greatest thickness, about 2,000 feet.

Subgelisol: Unfrozen ground beneath permafrost.

Talik: Permanently unfrozen ground in regions of permafrost.

Mark Vogan, who keeps a close eye on weather across the United Kingdom for us, sends us these beautiful shots of snow in the Scottish Highlands. You can see how breathtaking the region is just by taking in Mark’s photos. He writes:

“Had a wonderful day. A drive from our home town of Kirkintilloch to the highland's capitol of Scotland, Inverness. It was a cold, frosty morning here and on our 150+ mile journey up through the magnificant Grampian Mountains and Cairngorms National Park to Inverness we encountered very cold temperatures. Indeed I sprayed the windshield continuously with antifreeze because of the road salt creating a dirty film of the windshield. This froze instantly to not only the windshield but created an ice buildup on the wipers, which at one point I needed to stop and scap off the ice from the wipers which became useless.”

Mark reports Loch Ness is among these images. Thanks Mark for this report and for sharing these awesome images of Scotland with us!

--By Tom Skilling, WGN-TV Chief Meteorologist

The lake snow is finally easing in western Lower Michigan, having buried sections of the snowbelt there under more than a foot of snow. Reports in to the National Weather Service there indicate as much as 17” of snow fell not far from South Haven, Michigan at Monterey in Allegan County. Nearby Dorr was hit by 13” while Wayland reported 11” and Saugatuck tallied 11”. Farther south, parts of Berrien County have received as much as 5-7” of snow.

Our friend and observer John Gehr from Holland, Mich., has sent us these spectacular (and beautiful) shots of the snow in his area. MANY THANKS , John!

More snow is headed into Chicago Friday night into early Saturday morning—perhaps an inch, perhaps a little more—as milder air overruns the retreating arctic chill which sent temperatures plunging overnight as low as -18.6-degrees west of the city in DeKalb County (thanks to David Lindgren at the University of Illinois experimental farm for that report) as well as -17-degrees at Sugar Grove. Though strong warming and even some rain arrives on howling southerly winds (30+ mph gusts aren’t out of the question) Monday into Monday night, cold air resurges into the region Tuesday and computer models we’re examining, though varied on timing and details, suggest the potential for one or more potentially significant snowfalls next week.

The European Center’s latest model run is hinting at a potentially important system with possible snow over at least sections of the Chicago metro area later Tuesday into Wednesday morning. And the National Weather Service’s global model (the “GFS") continues to indicate—as it has in a number of its recent forecast cycles—another storm, a potential snow-producer---could be headed into the Midwest late next week. These are early trends hardly carved in stone, but the fact they’ve appeared with some regularity over a series of days flags the systems as ones to watch.
--By Tom Skilling, WGN-TV Chief Meteorologist

This morning’s light pillars made for a “fantastic sunrise”, says Plainfield Emergency Management Agency’s Heidi Kelly.

Photo courtesy: Heidi Kelly of Plainfield Emergency Management Agency

These photos of Wednesday morning's light pillars was taken by Daniel Ruggiero on the Fermilab grounds in west suburban Batavia. This morning's frigid temperatures helped support the light refracting/reflecting ice crystals which produce the light pillar effect.

Many thanksd Dan!

Photo courtesy: Dan Ruggiero, Fermilab, Batavia, Ill.

I can't remember a recent meteorological event which has prompted more e-mails from our viewers. I want to share with you some of the scores of photos I received of this morning's "light pillars"--an optical effect which caught the eye of so many across the Chicago metro area. Light pillars--vertical columns of light emanating from streetlights, parking lot lights and other unshielded outdoor light sources--are a cold weather phenomenon most frequently observed in the planets optical regions. They are produced as plate shaped ice crystals, more like the crystals you'd expect to find in cirrus clouds, refract and reflect light, a development which leads to vertical shafts of light.

MANY THANKS to all who forwarded photos of the event to me!

Tom Skilling

Photo courtesy: Jim Bayne, Chicago

Photo courtesy: Tim Ruttler, Homer Glen, Ill

Photo courtesy: Robert Ooms, Bolingbrook, Ill.

Photo courtesy: Doug Neufeldt, Hanover Park, Ill.

Photo courtesy: Phil Castrogiovanni, Chicago

--By Tom Skilling, WGN-TV Chief Meteorologist

Icebox of the nation

Communities claiming to be the “nation’s icebox” include Pellston, Mich., International Falls, Minn., Fraser, Colo., Truckee, Calif., Stanley, Idaho, and West Yellowstone, Mont. Here are their average annual temperatures. You be the judge.

34.8º Fraser, Colorado
35.4º Stanley, Idaho
36.5º International Falls, Minnesota
40.2º West Yellowstone, Montana
42.7º Pellston, Michigan
44.4º Truckee, California

Jay Kleeman shares these wintry shots of the past weekend’s brutally cold air. From ice crytals above Lake Michigan and the Chicago River to ice covered ducks, the coldest air in 11 months here and the first sub-zero spell in January of the past four years made for one wintry environment! Thanks for the beautiful shots, Jay!

Tom Skilling

Photos courtesy: Jay Kleeman

The “steam” is actually composed of ice crystals which form through a process known as sublimation—when evaporating water changes directly to a solid rather than going through the gas phase. These photos were taken by Rob Kleeman on Saturday. Thanks Rob!

-Tom Skilling

--By Paul Dailey, WGN Weather Center Meteorologist

-20ºF

At Chicago, temperature readings that cold (or colder) are exceedingly rare occurrences. So rare, in fact, that they have appeared only 15 times since the inception of Chicago's official temperature records on November 1, 1870.

If you experienced any of them, chances are you have a vivid memory of the event.

Here they are, listed in chronological order:

1 -21º Sunday, Dec. 22, 1872
2 -23º Tuesday, Dec. 24, 1872
3 -20º Saturday, Jan. 9, 1875
4 -20º Monday, Jan. 25, 1897
5 -21º Thursday, Feb. 9, 1899
6 -26º Sunday, Jan. 10, 1982
7 -25º Saturday, Jan. 16, 1982
8 -23º Sunday, Jan. 17, 1982
9 -21º Friday, Dec, 23, 1983
10 -25º Saturday, Dec. 24, 1983
11 -20º Friday, Jan. 20, 1984
12 -22º Saturday, Jan 21, 1984
13 -23º Saturday, Jan. 19, 1985
14 -27º Sunday, Jan. 20, 1985
15 -21º Tuesday, Jan. 18, 1994

--By Tom Skilling, WGN-TV Chief Meteorologist

Wind chill temperature: The temperature of still air that would remove heat from an exposed human body as quickly as it is being removed by the existing combination of actual air temperature and wind speed. Humidity and evaporative cooling are not taken into consideration.

Apparent temperature: The heat index; using air temperature and relative humidity, how hot it feels to an "average" person (147 pounds) wearing light clothing and walking 3.1 m.p.h. in a wind that is blowing 5 m.p.h.

Temperature: A measure of the internal energy that a substance contains. The degree of hotness or coldness of a substance, or of the environment. Air temperature is the most frequently measured atmospheric variable.

Monday, Jan. 14, will mark the debut of the redesigned Chicago Tribune weather page prepared by Tom Skilling and the WGN Weather Center team. The weather page changes are a part of the redesign of the entire newspaper to update its appearance and enhance its readability.

Let us know what you think of the changes that we have made. You can email your comments to asktomwhy@tribune.com.

In our Dec. 6, 2007, Ask Tom Why column in response to Katie Schoeling's question on winter tornadoes, we stated that the immediate Chicago area had never recorded a tornado during December, January or February. That statement is no longer true.
Palatine resident David Hammer was kind enough to provide us with an article from the Dec. 14, 1951, issue of the "Daily Herald" that reported a tornado in the Arlington Heights area on the evening of Dec. 6, 1951 -- an event previously catalogued as wind damage.
With the help of Jim Allsopp, Chicago's NWS Warning Coordination Meteorologist, and a group of tornado experts, the consensus was that the Chicago area did indeed experience a winter tornado. More information about this storm is available at the National Weather Service's web site.
Ironically, Nature provided the Chicago area a second winter tornado last Monday afternoon when an EF-3 twister struck in northwest McHenry County near Harvard. The graphic below focuses on the Chicago area's only two winter twisters.

With arctic air returning to the Chicago area and the Midwest this week, snow and colder weather are on tap instead of the recent siege of unseasonable warmth, rain and storminess.
A series of cold fronts are expected to pass through the area, each accompanied by a period of snow or snow showers and followed by a shot of arctic air. The coldest air will hold off until the end of next week, when strong northerly flow is expected to keep highs in the teens and send overnight lows below zero for the first time this winter. However, a build-up of at least an inch or two of snow cover here will be necessary to help maintain the strength of the incoming cold air.
Levels are falling, but many areas on the Illinois, Kankakee and Iroquois rivers (along with many streams and creeks south of Chicago) remain above flood stage. With colder weather ending the threat of additional rain, river levels should continue to fall over the next few days.
--By Steve Kahn, WGN Weather Center Meteorologist

Saturday's expected 40-degree high may be the city's last maximum temperature to reach that level for quite a while.
Frigid air which has been confined to areas far to the north across northern Canada in recent days is ready to begin a plunge south into the United States again, propelled by a buckling of the jet stream that will open the arctic floodgates.
The cold air will arrive here in progressively colder stages, each proceeded by a period of snow that should re-establish some snow cover in the region.
Though a large snowfall does not appear to be in the cards, even a few inches of snow would go a long way in sustaining the newly arriving deep freeze.
Cold air swept into Iraq Friday, where Baghdad experienced its first snowfall in memory. The snow, mixed with rain at times, melted quickly. High temperatures there in the middle 30s were more than 20 degrees below normal.
--By Steve Kahn, WGN Weather Center Meteorologist

As snow flurries end this morning in the wake of low pressure departing to the east, another strengthening low pressure system in the northern Plains is headed this way and forecast to give northern Illinois more snow later Saturday night and Sunday.
Temperatures will be slowly trending lower with succeeding fast-moving low pressure systems next Monday and Wednesday. Frigid arctic air will follow a strong cold front next Wednesday and dominate the remainder of the week.
Unusual January severe weather broke out along the mid-Gulf Coast Thursday. By Thursday evening, five people were injured and extensive property damage was reported after 17 tornadoes hit Mississippi, Alabama and Louisiana). To top it off, three tornado touchdowns occurred in the southwest corner of Washington in Clark County. The nation's tornado total thus far this January is more than triple that recorded as of this date last year (87 vs. 27).
--By Paul Dailey, WGN Weather Center Meteorologist

This week's unseasonable warmth is now history, and is soon to be replaced by colder weather and snow. Temperatures during the three-day Sunday-Tuesday warm spell averaged 30 degrees above normal, placing it fourth among similar January warm spells since 1871.
The next storm system which will arrive Thursday will begin as rain here, but a change over to snow can be expected Thursday night into Friday as colder air sweeps into the area on the storm’s backside. Heaviest accumulations appear headed for Wisconsin and Michigan where up to 6 inches of snow could fall.
The mercury will continue its downslide through the weekend, and the latest ensemble of long-range computer forecasts predict even colder air is to reach the Midwest and Northeast in the period beyond Jan. 20.

--By Steve Kahn, WGN Weather Center Meteorologist

The warm spell made this just the 4th January since 1928 to produce 3 consecutive high temps of 55°+. Thunderstorm-driven severe weather and heavy rains have moved east, leaving behind tornado damage and rain-swollen rivers. Only the second January tornado in this area since at least 1950 cut a 15-mile swath from Popular Grove to Harvard in McHenry County Monday afternoon. Later Monday into Tuesday, “training” storms, repeatedly developing and moving over the same area ahead of a slow-moving weather system gave widespread rain totals from 1 to 5”. A band of 4”+ rainfall extended from Pontiac in Livingston County east into southern Newton and Jasper Counties in Indiana. Due to saturated soils, most of the rain was runoff into area creeks and streams, resulting in major rivers south of I-80 being near or in flood. Temps will fall the remainder of the week with highs next week in the low to mid 20s.

--By Paul Dailey, WGN Weather Center Meteorologist

Swarms of at least 30 tornadoes blasted portions of the Midwest from southwest Missouri to southeast Wisconsin Monday afternoon and evening, producing at least one fatality, numerous injuries and swaths of devastation. Prior to Monday, the state of Wisconsin had only one January twister on record, occurring near Janesville back in 1967, while the closest twister to northeast Illinois struck near Kankakee on January 24, 1950.
All that changed in less than an hour on an unseasonably warm mid 60º January afternoon as a series of twisters inflicted major damage along a line from just north of Rockford to just west of Racine in southeast Wisconsin. At least three people were injured in Boone county where storm debris made roads impassible near Poplar Grove. Some of the worst damage was inflicted near New Munster, Wisconsin west of Kenosha where 12 homes were destroyed.

--By Steve Kahn, WGN Weather Center Meteorologist

It was a historic day across Northern Illinois Monday! Not only did Chicago's official high temperature of 65º fall just 2º shy of the warmest January temperature on record(67º January 25, 1950), but the area witnessed only the second January tornado since at least 1950.

These spectacular post-tornado photos were taken at the Edwards Apple Orchard in Poplar Grove, IL—one of the first areas hit by the twisters Monday afternoon around 3:35 pm—by Valparaiso meteorology student Aaron Brackett. While chasing this rare January twister, Aaron tells us that he was the first to arrive on the scene. Thanks much Aaron for sharing these photos with us.

--Bill Snyder, WGN-TV weather producer

Photo courtesy: Aaron Brackett

The tornado watch for the Chicago metropolitan area has been canceled. Scattered showers will continue overnight with some heavier rain and possibly more thunderstorms developing late tonight and Tuesday morning.

Steve Kahn WGN-TV Weather Center Meteorologist

ENTIRE CHICAGO AREA UNDER A TORNADO WATCH UNTIL 9 PM THIS EVENING

Fast-moving tornadic thunderstorms swept across portions of extreme northern Illinois into southeast Wisconsin this afternoon from north of the Rockford area to near Kenosha. The storms left a trail of damage from the Machesney Park area north of Rockford east northeast through Poplar Grove passing north of Harvard before moving into southeast Wisconsin causing damage near New Munster in Kenosha County. Two twisters were also sighted near the Kenosha County Airport.

The twisters damaged numerous homes, downed trees, transformers and powerlines. High winds were also reported with gusts to 80 m.p.h. at Hebron in far northern McHenry County. A semi was overturned north of Harvard. Hail also accompanied the storms.

The storms erupted in an unseasonably warm record-breaking air mass that sent the mercury in Chicago to a balmy 65º shattering the day's previous record high of 59º set 101 years ago in 1907.

The entire Chicago Metropolitan area along with northwest Indiana remains under a tornado watch until 9 p.m.

Steve Kahn WGN-TV Weather Center Meteorologist

Not only did Chicago eclipse the 54 degree record high originally set in 1907 when the mercury reached 60 degrees Sunday afternoon, but the day's 41 degree low also established a new record high minimum, wiping the previous record of 40 degrees (also set in 1907) from the books.
With a strong southerly flow of air expected to blast the city again on Monday, it's a good bet that more records will tumble. With high temperatures forecast to reach the lower 60s, the Jan. 7 record high of 59 degrees (set in 1907) appears to be in jeopardy, and with downstate readings on Sunday climbing well into the 60s, it is not out of the question that the city's all-time January high temperature of 67 degrees, established on Jan. 25, 1950, could be equaled or surpassed.
However, the unseasonable warmth will be fleeting. Colder air poised to sweep into the area beginning late Tuesday sets up a gradual temperature decline expected to last for the rest of the week.
--By Steve Kahn, WGN Weather Center Meteorologist

Just three days after Thursday morning’s 0º low, Chicago area temperatures are threatening to break Sunday’s century-old 54º record high established in 1907. The stunning 50º+ temperature rise is rapidly devouring the area’s snow pack, releasing more than half an inch of meltwater into area soils. Coupled with the potential for copious rainfall from an approaching storm, area rivers, streams and creeks may experience rapid rises.
The storm promises to be a potent offshoot of the major system that crippled portions of the West with 100 m.p.h + winds, up to 6 feet of mountain snow and mudslide triggering deluges.
Being January, the abnormal warmth will, of course, be fleeting, with colder weather and some snow showers set to return to the Chicago area and the Midwest later in the week.
--By Steve Kahn, WGN Weather Center Meteorologist

Southerly winds generating low-level cloudiness, fog and a drizzle/light shower mix are the driving forces behind an expected rapid snowmelt over northeast Illinois this weekend. Temperatures rise steadily into the lower 40s today, hover at that level overnight, and then climb into the lower 50s Sunday -- possibly approaching the record high of 54 degrees set 101 years ago. This strong southerly flow over the central Plains and Midwest has been set up by a monster low pressure system off the northwest U.S. coast. Winds gusting over 100 m.p.h. have pounded northern California. Santa Clara, Ben Lomond and Big Sur, all south of San Francisco, respectively received 10, 8 and over 6 inches of rain. Meanwhile, just to the east in the higher Sierras, Aspendell had 16 inches of snow in 4 hours and Placer had 163 m.p.h. winds.
The storm will move across the Rockies, developing a low in the central Plains that will bring heavy rains and potential flooding here early next week.
--By Paul Dailey, WGN Weather Center Meteorologist

As frigid high pressure moved east, southerly flow returned to Illinois Thursday. The opening three days of January 2008 averaged some 10° below normal, 25° colder than a year ago. Arctic air penetrated deep into Florida with snow flurries observed at Daytona Beach. Citrus growers were pressed into protective actions with 29° at Tampa, and 31° at Orlando. Miami hit a low of 39°. Noticeable warming begins today, then picks up momentum this weekend. The strong weather system presently lashing the west coast with damaging winds and heavy rains (snow at higher elevations) will cross the Rockies and force the development of a low pressure system that will move through the Midwest early next week. This will mean an extended period (into next Tuesday) of southerly flow that will feed mild moist air over Northeast Illinois’ shrinking snow layer resulting in drizzle, fog and showers.
--By Paul Dailey, WGN Weather Center Meteorologist

Early-bird risers who step into sub-zero temperatures this morning might find it hard to believe, but it’s true: The city will be basking in 50° readings (or higher) in another three days.
A major weather pattern shift begins haltingly on Friday as upper winds that have been blowing with considerable strength from the northwest gradually diminish and are replaced by southwesterlies. Southwest winds, surface and aloft, strengthen on Saturday, then persist through Monday.
Mild, moist air from the Gulf of Mexico arrives here on Saturday and, as that air spreads across our snow-covered landscape, it becomes a recipe for a heavy gray overcast, widespread fog and plenty of light rain and drizzle through the weekend. The multi-inch layer of ice and crusty snow that blankets the area today will be history by Monday.
-By Richard Koeneman, WGN Weather Center Meteorologist

Chicagoans shivering in today's arctic cold can take consolation in the understanding that they are not alone.
Very cold air -- bitterly cold in some regions -- holds all of the nation east of the Rocky Mountains in its frigid grip. That constitutes literally two-thirds of the Lower 48.
Lake-effect snow swirling off Lake Michigan continues to cause problems today for residents of the snow-belt areas of northern Indiana and southwest Lower Michigan (and downwind of the other Great Lakes, as well) -- but they take that in stride.
Residents of the Deep South, however, are far less accustomed to the presence of harshly cold winter temperatures. Freezing conditions are pushing literally into south Florida -- and that's not the end of it. "Northern air," greatly modified but still chilly, is forecast to push across the north half of the Caribbean Sea by Friday.
--By Richard Koeneman, WGN Weather Center Meteorologist