MESOSCALE DISCUSSION 0017
   NWS STORM PREDICTION CENTER NORMAN OK
   0900 PM CST FRI JAN 16 2004
   
   AREAS AFFECTED...NERN IA/SRN WI/NRN IL
   
   CONCERNING...FREEZING RAIN 
   
   VALID 170300Z - 170900Z
   
   LIGHT TO MODERATE FREEZING RAIN WITH HOURLY RATES APPROACHING 0.05
   TO 0.10 INCH WILL SPREAD EWD FROM NERN IA ACROSS SRN WI/NRN IL OVER
   THE NEXT 3 TO 6 HOURS.
   
   AS OF 0240Z...REGIONAL RADAR MOSAIC SHOWED AN EVOLVING PRECIPITATION
   SHIELD OVER MUCH OF IA EWD INTO SRN WI/NRN IL. CLOSE INSPECTION OF
   WATER VAPOR IMAGERY SUGGEST THAT A WEAK VORTICITY MAX CURRENTLY
   TRANSLATING EWD ACROSS WRN IA COUPLED WITH LOW-LEVEL WAA/ISENTROPIC
   ASCENT IS LIKELY RESPONSIBLE FOR THIS ONGOING PRECIPITATION. WHILE
   MUCH OF IA HAS REMAINED AT OR ABOVE FREEZING...LOCATIONS GENERALLY N
   AND E OF MCW TO MLI TO MMO ARE SUB-FREEZING...WITH AN INCREASING
   RISK OF ICE ACCUMULATION. 
   
   LATEST MODEL GUIDANCE AND REFLECTIVITY TRENDS BOTH SUGGEST THE EWD
   MOVEMENT/DEVELOPMENT OF PRECIPITATION SHIELD OVER THE NEXT 3 TO 6
   HOURS AS SHORTWAVE TROUGH MOVES ACROSS IA. FORECAST SOUNDINGS FOR
   AREAS N OF INTERSTATE 80 AND S OF INTERSTATE 90/94 INDICATE LARGELY
   FREEZING RAIN WITH HOURLY RATES APPROACHING 0.10 INCH. SLEET MAY MIX
   IN ALONG THE NRN PERIPHERY OF THIS AREA WHERE WARM NOSE BASED JUST
   ABOVE 850MB WILL REMAIN NEAR 0 TO +2C.
   
   ..MEAD.. 01/17/2004
   
   
   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...
   
   43359313 43589084 43288799 42638702 41618743 41448872
   42429290