MESOSCALE DISCUSSION 0031
   NWS STORM PREDICTION CENTER NORMAN OK
   1157 AM CST WED JAN 05 2005
   
   AREAS AFFECTED...NRN/CNTRL IL/IND/OH POSSIBLY INTO PA
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 051757Z - 060000Z
   
   CORRIDOR OF FREEZING RAIN AND SLEET IS EXPECTED TO INCREASE IN
   INTENSITY THIS AFTERNOON ACROSS PORTIONS OF NRN/CNTRL IND/OH...AND
   POSSIBLY INTO PA. HOURLY RATES OF .05 TO .10 INCH/HOUR WILL BE
   COMMON WILL LOCALIZED AMOUNTS EXCEEDING .15 TO .20 INCH/HOUR.
   
   VIGOROUS SHORTWAVE TROUGH OVER THE CNTRL/SRN HIGH PLAINS IS FORECAST
   TO INTENSIFY AS IT TRANSLATES ENEWD TOWARD THE MIDDLE/LOWER MO
   VALLEY TODAY. AS THIS OCCURS...ATTENDANT SURFACE/850 MB LOWS WILL
   DEEPEN OVER THE MIDDLE MS/LOWER OH VALLEYS...EFFECTIVELY ENHANCING
   DOWNSTREAM BAROCLINIC ZONE ALONG/JUST N OF THE OH RIVER. HEIGHT
   FALLS ASSOCIATED WITH APPROACHING SHORTWAVE TROUGH IN CONJUNCTION
   WITH PERSISTENT WAA ALONG NOSE OF 40-50 KT WSWLY LLJ AXIS ARE
   EXPECTED TO MAINTAIN PRECIPITATION SHIELD N OF FRONTAL ZONE OVER THE
   OH VALLEY THROUGH THE AFTERNOON.
   
   SYNTHESIS OF CURRENT SURFACE OBSERVATIONS WITH FORECAST SOUNDINGS
   AND PLAN VIEW THERMODYNAMIC FIELDS SUGGEST THAT PRIMARY CORRIDOR OF
   FREEZING RAIN WILL PERSIST FROM NEAR CMI EWD TO MIE TO MFD WHERE .05
   TO .10 INCH PER HOUR RATES WILL BE COMMON. SLEET...POSSIBLY MIXING
   WITH FREEZING RAIN AND/OR SNOW...WILL BE MORE LIKELY ACROSS NRN
   PORTIONS OF IND/OH. DIRECT MESOSCALE CIRCULATIONS ARISING FROM THE
   INCREASED LOW-LEVEL BAROCLINICITY MAY CONTRIBUTE TO NARROW W-E
   ORIENTED PRECIPITATION BANDS WHERE HOURLY PRECIPITATION RATES MAY
   APPROACH .15-.20 INCH/HOUR.
   
   ..MEAD.. 01/05/2005
   
   
   ...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...CTP...PBZ...CLE...ILN...DTX...IWX...IND...LOT...ILX...
   
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