Friday Afternoon Update

Just received a report of rain changing to snow reported in

Creston with thunder! 

0206 PM     SNOW             BELVIDERE           
03/02/2012  U0.0 INCH        BOONE              

GRASSY AREAS ARE GETTING WHITE AND SNOWFLAKES ARE GETTING
BIGGER AS OF 2 PM. REPORT RELAYED BY BROADCAST MEDIA.

2:00pm Update:  Moderate to heavy snowfall is now falling.  The snow has begun to already accumulate on roadways and grassy surfaces.  Road conditions will deteriorate by this evening.  Visibility is down to a quarter mile where the heavy snow is falling.



Current Headlines:
Winter Storm Warning for Winnebago, Ogle, Boone, McHenry counties (this replaces the Winter Storm Watch)

Winter Storm Warning for Green, Rock and Walworth counties

Winter Weather Advisory for Stephenson, Jo Daviess, Carroll, Whiteside AND now includes Lee and DeKalb counties.

1:00pm Update: Light rain has occasionally been mixing with sleet and snow late this morning while heavy snow has been falling across southwest Wisconsin and northeast Iowa.  A heavier band of snow is occurring from Madison southwest through Dubuque to just west of the Quad Cities.  In fact, our StormTrack radar had detected some lightning within this band which may indicate some thundersnow.

Low pressure is currently near Springfield, IL with severe thunderstorms out ahead of the low and heavy snow falling on the backside.  This low has rapidly been intensifying and will continue to do so through the evening.  As as result cold air is being drawn into the storm from west/southwest Wisconsin through eastern Iowa.  The rain/sleet/snow mixture will begin change over to snow after about 2pm from west to east.  Keep in mind the transition will be sooner for locations west of Rockford.  Once this change over occurs snowfall rates could approach one inch (or higher) within some of the more moderate snow bands.  Snow totals could reach six inches with locally higher amounts in places where the heavy bands set up.  The snow will be heavy and wet as temperatures will range from about 32° to 36° when the snow begins to fall.  While there may initially be some melting on contact, higher snowfall rates may help compensate for this which will lead to deteriorating  road conditions by this evening.  This is not going to be a long duration snowfall event and once the low moves into southern Michigan by tonight the snow will quickly come to an end overnight.  However, because we're expecting the heaviest of the snow to fall within a six hour period this will quickly cause conditions to deteriorate once the snow begins to fall.  Where the snow has been falling in eastern Iowa visibility has been reduced to less than a quarter mile at times.  Winds are also expected to increase and gradually switch from the northeast to the northwest with gusts that may reach 30 mph or higher. 

12:30pm Update: A band of heavy snow is beginning to set up across far northwest Illinois and northeast Iowa early this afternoon.   Within this band snowfall rates will likely reach, or exceed, one inch per hour.  This band will move eastward throughout the afternoon.  There are a few light sprinkles/rain showers out this morning across north-central Illinois but once the transition to all snow occurs it will fall at a fairly heavy pace as the low moves further east and colder air wraps in.