WINTER WEATHER ADVISORY COULD SWITCH TO WINTER STORM WARNING


    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 THE WINTER STORM WATCH IS NO LONGER IN
    EFFECT.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.


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