MESOSCALE DISCUSSION 0050
   NWS STORM PREDICTION CENTER NORMAN OK
   0640 AM CST SUN JAN 27 2013
   
   AREAS AFFECTED...CENTRAL AND ERN IA/FAR NERN MO/WEST CENTRAL AND FAR
   NWRN IL/PART OF SOUTH CENTRAL-SERN MN/FAR SWRN WI
   
   CONCERNING...FREEZING RAIN 
   
   VALID 271240Z - 271745Z
   
   SUMMARY...FREEZING RAIN WILL CONTINUE TO DEVELOP AND SPREAD NEWD
   ACROSS CENTRAL...NRN AND ERN IA...FAR NERN MO AND WEST CENTRAL IL
   THROUGH 15Z...AND THEN REACH PARTS OF SOUTH CENTRAL AND SERN
   MN...FAR SWRN WI AND FAR NWRN IL BETWEEN 14-18Z. THE GREATEST
   FREEZING RAIN RATES SHOULD RANGE FROM 0.05-0.1 INCH PER HR. BY LATE
   MORNING...A SUBSTANTIAL INCREASE IN LOW LEVEL WAA MAY ALLOW SURFACE
   TEMPERATURES FROM SOUTH OF DSM TO FAR SERN IA...WEST CENTRAL IL AND
   FAR NERN MO TO RISE ABOVE 32 F...ENDING THE FREEZING RAIN THREAT IN
   THOSE AREAS.
   
   DISCUSSION...AT 12Z...REGIONAL RADAR IMAGERY INDICATED A 90 MILE
   WIDE BAND OF PRECIPITATION EXTENDING FROM NWRN IA THROUGH SOUTH
   CENTRAL AND SERN IA INTO ERN MO WITH SURFACE OBSERVATIONS INDICATING
   A MIX OF FREEZING RAIN AND POSSIBLY SLEET...FREEZING DRIZZLE AND/OR
   SNOW IN SOME LOCATIONS. HOWEVER...ONCE THE LOWER TROPOSPHERE BECOMES
   SATURATED AIDED BY EVAPORATIVE COOLING AND A WARMING IN THE 800-900
   MB LAYER BECOMES MORE PRONOUNCED PER WAA...FREEZING RAIN SHOULD
   BECOME THE PRIMARY PRECIPITATION TYPE. THIS THREAT WILL INITIALLY BE
   A CONCERN FROM NORTH CENTRAL...CENTRAL AND SERN IA INTO FAR NERN MO
   AND WEST CENTRAL IL. RECENT RADAR IMAGERY ALSO SHOWED A NEW AREA OF
   PRECIPITATION DEVELOPING/EXPANDING IN AREAL COVERAGE OVER NERN KS
   INTO SERN NEB. THIS ACTIVITY MAY BE ATTENDANT TO STRONGER DEEP LAYER
   ASCENT WITHIN THE EXIT REGION OF A 50-60 KT SWLY MIDLEVEL JET
   ACCOMPANYING THE CENTRAL HIGH PLAINS SHORTWAVE TROUGH.
   
   FARTHER NE AND N...12Z SOUNDINGS AT DVN/MPX SHOWED DRY AIR REMAINING
   IN THE LOWER TROPOSPHERE. GIVEN SURFACE DEWPOINTS ARE IN THE TEENS
   ACROSS ERN IA/NWRN IL/SWRN WI AND SRN MN...EVAPORATIVE COOLING
   SHOULD HELP TO MAINTAIN SURFACE TEMPERATURES BELOW 32 F THIS MORNING
   AND SUPPORT FREEZING RAIN AS THE PREDOMINANT PRECIP TYPE.
   
   AN INCREASE IN DEEP LAYER ASCENT IS EXPECTED ACROSS THE DISCUSSION
   AREA THIS MORNING AS DPVA WITH THE SHORTWAVE TROUGH MOVES INTO THIS
   REGION AND LOW LEVEL WAA STRENGTHENS ALONG THE NOSE OF 40-50 KT SWLY
   LLJ EXPECTED TO EXTEND INTO SRN IA BY 18Z. THESE FACTORS SHOULD AID
   IN INCREASING PRECIPITATION RATES AND GIVEN THE STRENGTHENING LLJ
   INTO SRN IA...FORECAST SOUNDINGS SHOW A STRONG WARM NOSE ABOVE THE
   SUB FREEZING SURFACE TEMPERATURES.
   
   ..PETERS.. 01/27/2013
   
   
   ATTN...WFO...ILX...MKX...LSX...DVN...ARX...MPX...DMX...EAX...
   FSD...
   
   LAT...LON   40939335 42049436 43319529 43939478 43989180 43139069
               42329019 41418996 40259015 39649081 40369253 40939335