With the precipitation of the present winter storm system already beginning, the precipitation has been mainly rain across the area. Temperatures are above freezing, and snow might not begin until about 6:00 p.m. That's the good news for rush hour commuters.
The bad news is that a Winter Storm Warning could still be activated later today or this evening. The area of heaviest snow could still shift south toward Interstate 88. The timing of freezing temperatures and heavy precipitation are a major factor. One thing is certain: The snow will be heavy and wet "Heart Attack Snow."
As the storm approaches, the deepest snowfall fall is directly on the northwest suburbs of northwest Cook County and the northern third of Cook County; and including the northern two-thirds of Kane County, the southern half of McHenry County and more than three-fourths of southern Lake County. Thundersnow is still possible with embedded thunderstorm during snowfall.
WINTER WEATHER ADVISORY
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE CHICAGO IL
1110 AM CST THU FEB 23 2012
...RAIN TO CHANGE TO A WET SNOW AND BE HEAVY AT TIMES TONIGHT..
.RAIN WILL CHANGE TO A WET SNOW FROM WEST TO EAST ACROSS THE AREA
THROUGH THIS EVENING AS A COMPLEX LOW PRESSURE EVOLVES ACROSS
SOUTHERN ILLINOIS AND INDIANA. THE SNOW WILL BE HEAVY AT TIMES
THIS EVENING...ESPECIALLY IN THE HOURS JUST AFTER CHANGEOVER TO
SNOW. SOME ACCOMPANYING THUNDER IS POSSIBLE...AND WHERE THIS OCCUR
THERE WILL BE LOCALIZED HIGHER AMOUNTS. THE MOST FAVORED AREA TO
SEE LOCALIZED HIGHER AMOUNTS GREATER THAN SIX INCHES IS ACROSS
DEKALB...KANE...DUPAGE...AND NORTHERN COOK COUNTIES. THE SNOW WILL
GRADUALLY TAPER FROM WEST TO EAST ACROSS THE AREA LATE TONIGHT
THROUGH FRIDAY MORNING.
LAKE IL-DUPAGE-COOK-WILL-
INCLUDING THE CITIES OF...WAUKEGAN...WHEATON...CHICAGO...JOLIET
1110 AM CST THU FEB 23 2012
...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
9 AM CST FRIDAY...
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM 6 PM THIS
EVENING TO 9 AM CST FRIDAY. THE WINTER STORM WATCH IS NO LONGER IN
EFFECT.
* TIMING...RAIN WILL CHANGE TO A WET SNOW ACROSS FAR NORTHEAST
ILLINOIS...INCLUDING CHICAGO...EARLY THIS EVENING. SNOW MAY
BECOME HEAVY AT TIMES DURING THE EVENING AND EARLY OVERNIGHT
HOURS...BEFORE GRADUALLY TAPERING IN INTENSITY INTO EARLY FRIDAY
MORNING.
* ACCUMULATIONS...FOUR TO SEVEN INCHES...WITH THE HIGHEST AMOUNTS
ACROSS DUPAGE...NORTHERN COOK...AND SOUTHERN LAKE COUNTIES.
* MAIN IMPACT...HEAVY WET SNOW MAY FALL AT RATES GREATER THAN AN
INCH PER HOUR AFTER 8 PM. THIS WILL LIKELY RESULT IN QUICK
ACCUMULATION OF WET SNOW ON ROADS...RESULTING IN SLIPPERY AND
POTENTIALLY HAZARDOUS TRAVEL CONDITIONS.
* OTHER IMPACTS...IN ADDITION TO ACCUMULATION AND SLIPPERY
TRAVEL IMPACTS...STRONG WINDS WILL RESULT IN WIND WHIPPED
HEAVY WET SNOW CAUSING SEVERELY REDUCED VISIBILITIES THIS
EVENING THROUGH TONIGHT. DUE TO THE HIGH LIQUID CONTENT OF THE
SNOW...THOSE WITH HEALTH CONCERNS SHOULD USE CAUTION WHEN
SHOVELING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A WINTER WEATHER ADVISORY FOR SNOW MEANS THAT PERIODS OF SNOW
WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW
COVERED ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE
DRIVING.
Chicago/O'Hare
Lat: 41.98 Lon: -87.9 Elev: 658
Last Update on Feb 23, 1:51 pm CST
Light Rain Fog/Mist
38 °F
(3 °C)
Humidity: 86 %
Wind Speed: SE 8 MPH
Barometer: 29.49" (999.1 mb)
Dewpoint: 34 °F (1 °C)
Wind Chill: 32 °F (0 °C)
Visibility: 2.50 mi.
Chicago Midway Airport
Lat: 41.79 Lon: -87.75 Elev: 612
Last Update on Feb 23, 1:51 pm CST
Light Rain Fog/Mist
38 °F
(3 °C)
Humidity: 89 %
Wind Speed: SE 8 MPH
Barometer: 29.49" (999.5 mb)
Dewpoint: 35 °F (2 °C)
Wind Chill: 32 °F (0 °C)
Visibility: 5.00 mi.