MESOSCALE DISCUSSION 2186
   NWS STORM PREDICTION CENTER NORMAN OK
   0601 PM CST THU DEC 06 2007
   
   AREAS AFFECTED...SERN MO...SRN/CENTRAL IL..SWRN IND
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 070001Z - 070530Z
   
   A MIX OF MODERATE SNOW...SLEET AND FREEZING RAIN WILL MOVE FROM SERN
   MO INTO SRN/CENTRAL IL AND SWRN IND OVER THE NEXT 3-6 HRS. HRLY SNOW
   RATES BETWEEN 0.5 AND 1 INCH WILL BE POSSIBLE GENERALLY NE OF A LINE
   FROM 30 N OF STL TO 40 S OF BMG. SOUTH OF THIS LINE...A MIX OF SLEET
   AND LIGHT/MOD FZRA WITH HRLY RATES OVER 0.05 INCH WILL BE POSSIBLE
   THROUGH 04Z...BEFORE SHIFTING EAST OF THE AREA.
   
   STRONG LOW LEVEL WAA NOTED BY RECENT SFC OBS OF PERSISTENT PRESSURE
   FALLS OVER SRN MO AIDED BY A LOW LEVEL JET WILL CONTINUE TO SUPPORT
   EXPANSION OF PRECIPITATION EWD FROM ERN MO INTO SRN/CENTRAL IL AND
   SWRN IND THROUGH THE EVENING HOURS. OBS INDICATE THAT THE
   SN/FZRA/SLEET AXIS EXTENDS FROM NEAR STL SEWD INTO FAR SRN IL AT
   00Z. AS THE LOW LEVEL JET CONTINUES TO SHIFT EWD...THE MIXED
   PRECIPITATION ZONE AXIS SHOULD MOVE NEWD THROUGH THE EVENING.
   EVENTUALLY THE PRESENCE OF THE ELEVATED WARM LAYER WILL BECOME
   NEGLIGIBLE OVER CENTRAL IL AND SWRN IND...SUCH THAT LITTLE TO NO
   MIXED PRECIP IS EXPECTED TO DEVELOP. HOWEVER...GIVEN THE STRENGTH OF
   THE VERTICAL MOTION...MOD TO OCCASIONALLY HEAVY SNOW WILL BE
   POSSIBLE BETWEEN 02-06Z IN THESE AREAS.
   
   ..CROSBIE.. 12/07/2007
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
   SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
   TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
   FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.
   
   ATTN...WFO...LMK...IND...PAH...ILX...LSX...
   
   38368637 38078778 37778867 37768982 37909049 38249125
   38869139 39299127 39789035 39978958 40018865 40108751
   40058630 39838591 38798579