MESOSCALE DISCUSSION 0048
   NWS STORM PREDICTION CENTER NORMAN OK
   1015 PM CST MON JAN 26 2004
   
   AREAS AFFECTED...PARTS OF SRN IL/WRN KY THROUGH SRN/CNTRL IND
   
   CONCERNING...PRECIPITATION TRENDS....FREEZING RAIN/HEAVY SNOW 
   
   VALID 270415Z - 270715Z
   
   PRECIPITATION RATES WILL INCREASE FROM SOUTHERN INTO CENTRAL INDIANA
   NEXT SEVERAL HOURS.  PERIOD OF LIGHT TO MODERATE FREEZING RAIN IS
   LIKELY BEFORE HEAVY SNOW...AT TIMES IN EXCESS OF 1 INCH PER
   HOUR...DEVELOPS.
   
   STRONG MID-LEVEL JET STREAK CONTINUES TO PROPAGATE EAST
   NORTHEASTWARD THROUGH THE LOWER MISSISSIPPI.  AGEOSTROPHIC FORCING
   FOR UPWARD VERTICAL MOTION AND MID-LEVEL COOLING/DESTABILIZATION IN
   ITS EXIT REGION IS SUPPORTING AN AREA OF INCREASING CONVECTION
   ACROSS THE LOWER OHIO VALLEY.  THIS NOW INCLUDES AREAS NEAR/NORTH OF
   THE RIVER...FROM EXTREME SOUTHERN ILLINOIS INTO PARTS OF SOUTHERN
   INDIANA...WHERE SHALLOW SUB-FREEZING LAYER WEST OF SLOW MOVING
   SURFACE FRONT IS SUPPORTING FREEZING RAIN.
   
   MODELS ARE NOW SIMILAR IN SUGGESTING CONSOLIDATING/DEEPENING SURFACE
   LOW ALONG SURFACE FRONT ACROSS SOUTHEASTERN INDIANA DURING THE
   06-09Z TIME FRAME.  THIS IS SUPPORTED BY LATEST OBSERVATIONAL
   DATA...AND SUBSTANTIAL LOWER/MID TROPOSPHERIC COOLING WILL RESULT IN
   CHANGEOVER TO SNOW FROM SOUTHERN ILLINOIS/WESTERN KENTUCKY INTO
   SOUTHERN INDIANA AFTER 06Z.
   
   STRONGER FORCING IN EXIT REGION OF MID-LEVEL JET WILL SPREAD INTO
   SOUTHERN INDIANA DURING THE NEXT 2 TO 4 HOURS...WHERE/WHEN
   STRENGTHENING LOW-LEVEL FORCING FOR UPWARD VERTICAL MOTION IS
   EXPECTED TO BE ONGOING.  THIS WILL BE ACCOMPANIED BY SIGNIFICANT
   INCREASE IN SNOWFALL RATES...AS MAXIMUM LARGE-SCALE ASCENT COINCIDES
   WITH FAVORABLE DENDRITIC ICE CRYSTAL GROWTH TEMPERATURES IN THE MID
   TROPOSPHERE.
   
   3 TO 4 HOUR PERIOD OF HEAVY SNOW APPEARS LIKELY...INCLUDING ISOLATED
   CONVECTIVE BURSTS...SPREADING IN A SWATH ACROSS THE
   BLOOMINGTON/INDIANAPOLIS AREAS BY 12Z.
   
   ..KERR.. 01/27/2004
   
   
   ATTN...WFO...LMK...IND...PAH...ILX...
   
   38988761 39488708 40188670 40418597 39808535 39008589
   38188646 37938705 37568767 37618835 38058863 38598814