"The low pressure system now over southern Tennessee is moving northeastmore slowly than expected.
That is because it is intensifying more quickly and becoming stronger than models and data suggested it would, even through early this afternoon.
The National Weather Service has just upgraded the snow advisory to a heavy snow warning along and southeast of a line from Evanston to West Chicago to LaSalle, for 6" and locally heavier amounts, including Cook, DuPage, Grundy, Will, LaSalle and Kankakee counties until noon tomorrow. Everyone north and west of there is under a snow advisory for 3"-6" of snow through tomorrow morning. Because the storm is moving more slowly, it has become more than obvious that the snow will last later, and should continue until it tapers to flurries Sunday morning.
Final snow accumulations are expected to range from around 6" at Hoffman Estates, to 6"-8" at Naperville, to 4"-6" at DeKalb, and 2"-5" at our far western/northwestern campuses. However, latest radar trends are making me uncomfortable...and it is entirely possible DeKalb could see 6" or more storm total snowfall by morning.
Fiurthermore...because of the more northwest track of the storm, we will see stronger winds on Sunday. In fact, I now believe we'll see wind gusts as high as 30 MPH in the morning, and 25 MPH in the afternoon from the northwest. Because the snow is rather powdery, blowing and drifting snow will be a concern, mostly in open and rural areas.
Sorry, folks...this system intensified considerably more than expected, which slowed it down and is also forcing it to track much closer to us than anticipated even last night.
As of 4 PM...3.0" has come down with this system so far in DeKalb since it started early this morning."
From NWS CHICAGO
WWUS43 KLOT 152148
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
348 PM CST SAT DEC 15 2007
...WINTER STORM CONTINUES TO DEVELOP OVER THE LOWER MISSISSIPPI
.LOW PRESSURE ACROSS WESTERN TENNESSEE WILL CONTINUE TO STRENGTHEN
TONIGHT AS IT LIFTS NORTHEAST INTO THE OHIO VALLEY...REACHING
NORTHWEST OHIO BY SUNDAY MORNING. A STRONG UPPER LEVEL DISTURBANCE
IS SUPPORTING THIS DEVELOPMENT AND WILL SPREAD A BAND OF HEAVY
SNOW NORTHWEST OF THE STORM TRACK...ACROSS PARTS OF CENTRAL AND
NORTHERN ILLINOIS...AND INTO NORTHERN INDIANA. LIGHT SNOW WHICH
HAS OVERSPREAD PARTS OF NORTHERN ILLINOIS AND INDIANA TODAY WILL
GRADUALLY INTENSIFY THROUGH THE EVENING HOURS AND WILL CONTINUE
THROUGH THE OVERNIGHT HOURS AS THE LOW PRESSURE SYSTEM BEGINS TO
RAPIDLY DEEPEN. SNOW WILL GRADUALLY TAPER TO LIGHT SNOW AND
FLURRIES EARLY SUNDAY MORNING. TOTAL SNOW ACCUMULATIONS IN EXCESS
OF 6 INCHES ARE POSSIBLE MAINLY SOUTHEAST OF A LINE FROM EVANSTON
TO WEST CHICAGO TO MENDOTA.
INCLUDING THE CITIES OF...CHICAGO...OTTAWA...OSWEGO
348 PM CST SAT DEC 15 2007
...HEAVY SNOW WARNING IN EFFECT UNTIL 12 PM CST SUNDAY...
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A HEAVY SNOW
WARNING...WHICH IS IN EFFECT UNTIL 12 PM CST SUNDAY. THE SNOW
ADVISORY IS NO LONGER IN EFFECT.
LIGHT TO MODERATE SNOW WILL GRADUALLY INTENSIFY THROUGH THE
EVENING HOURS...WITH MODERATE TO HEAVY SNOW CONTINUING THROUGH THE
OVERNIGHT HOURS. STORM TOTAL SNOW ACCUMULATION IS EXPECTED TO
RANGE FROM UP TO 6 INCHES ACROSS THE EVANSTON...WEST
CHICAGO...AND MENDOTA AREAS...TO 6 TO 9 INCHES FROM CHICAGO AND
THE SOUTHERN SUBURBS TO JOLIET TO MORRIS. THE INCREASING INTENSITY
OF THE SNOW LATE THIS AFTERNOON INTO TONIGHT WILL MAKE FOR
HAZARDOUS TRAVEL ACROSS THE AREA THIS EVENING INTO THE OVERNIGHT
HOURS AS MANY ROADS BECOME SNOW PACKED. IN ADDITION TO THE HEAVY
SNOW ACCUMULATION...NORTH WINDS WILL STRENGTHEN THROUGH THE
EVENING WITH GUSTS TO 30 MPH POSSIBLE OVERNIGHT. THIS WILL RESULT
IN AREAS OF BLOWING SNOW AND REDUCED VISIBILITIES. SNOW WILL TAPER
TO LIGHT SNOW AND FLURRIES ON SUNDAY MORNING.
A HEAVY SNOW WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW ARE FORECAST
THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN EMERGENCY. IF
YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...FOOD...AND WATER IN
YOUR VEHICLE IN CASE OF AN EMERGENCY.