MESOSCALE DISCUSSION 0017
   NWS STORM PREDICTION CENTER NORMAN OK
   1153 AM CST MON JAN 03 2005
   
   AREAS AFFECTED...ERN IA/FAR NERN MO...PORTIONS OF NRN IL/SRN WI AND
   CENTRAL/SRN LOWER MI
   
   CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 
   
   VALID 031753Z - 032300Z
   
   A MIX OF LIGHT SNOW...LIGHT TO MODERATE FREEZING RAIN AND SLEET IS
   FORECAST TO DIMINISH FROM WEST TO EAST ACROSS ERN IA/NERN MO...NRN
   IL AND FAR SRN WI THROUGH 21Z. FARTHER EAST...A MIX OF SLEET AND
   MODERATE/POSSIBLY HVY SNOW WILL DEVELOP OVER PORTIONS OF CENTRAL/SRN
   MI FROM 20-00Z. HOWEVER...TEMPERATURES AROUND FREEZING WILL LIMIT
   SLEET/SNOW ACCUMULATIONS IN THIS REGION. HRLY ACCUMULATION RATES UP
   TO 0.15 IN WILL REMAIN POSSIBLE OVER PORTIONS OF ERN IA/FAR NERN MO
   INTO FAR NRN IL THROUGH 20Z.
   
   LATEST IR IMAGERY SHOWS THAT CLOUD TOPS CONTINUE TO REMAIN COLD
   INDICATIVE OF CONVECTIVE NATURE OF SLEET/ICE EVENT OVER THE MID MS
   VALLEY. STRONG AGEOSTROPHIC ASCENT DUE TO COUPLED JET STRUCTURE WILL
   MAINTAIN A BROAD ORGANIZED PRECIPITATION AREA AS IT MOVES FROM THE
   MID MS VALLEY INTO THE SRN GREAT LAKES REGION THROUGH THE AFTERNOON.
   SFC ANALYSIS INDICATES A REFLECTION OF THE STRONG MID/UPPER LIFT
   WITH A NE-SW ORIENTED SFC TROUGH OVER WRN IL AT 17Z. THE SFC
   FREEZING LINE SHOULD REMAIN IN PLACE THROUGH THE REMAINDER OF THE
   EVENT EXTENDING FROM NEAR IRK NEWD TO THE NRN CHICAGO SUBURBS. QUICK
   CESSATION OF VERTICAL MOTION WILL CONTINUE TO SPREAD W-E AND AID IN
   RAPID DIMINISHMENT OF WINTER PRECIPITATION ACROSS THE AREA BY 21Z.
   STRONG FRONTOGENESIS IS FCST TO MOVE THROUGH CENTRAL MI DURING THE
   20-00Z TIME FRAME. THUS...DESPITE RECENT RISE OF TEMPERATURES IN
   THIS REGION STRONG DYNAMIC LIFT WILL AID IN HVY SNOW DEVELOPMENT IN
   THE MID LEVELS AND PRECIPITATION FALL/WET-BULB EFFECTS /CURRENT
   DEWPTS NEAR 30/...SHOULD BE SUFFICIENT TO COOL THE LOW LEVEL
   THERMODYNAMIC PROFILE FOR A 1-2 HR PERIOD OF MODERATE TO POSSIBLY
   HVY SNOW FROM WEST TO EAST ALONG AND JUST NORTH OF THE I-96 CORRIDOR
   DURING THE 20-00Z PERIOD.
   
   ..CROSBIE.. 01/03/2005
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
   SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 00-01 UTC...
   06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
   RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
   USED FROM DECEMBER 1 THROUGH FEBRUARY 28.
   
   ATTN...WFO...DTX...GRR...LOT...ILX...MKX...LSX...DVN...
   
   43078794 42628953 42459049 42079120 41209162 40419183
   39999162 40349075 41029027 41638952 42208793 42488581
   42428370 42878294 43328325 43488481