MESOSCALE DISCUSSION 0527
   NWS STORM PREDICTION CENTER NORMAN OK
   0713 PM CDT THU APR 18 2013
   
   AREAS AFFECTED...PORTIONS OF ERN MN...NWRN WI
   
   CONCERNING...HEAVY SNOW 
   
   VALID 190013Z - 190515Z
   
   SUMMARY...A SHIELD OF MODERATE SNOW...WITH EMBEDDED HEAVY
   SNOW...WILL GRADUALLY SHIFT NEWD DURING THE EVENING HOURS. SNOW
   RATES OF 1 IN/HR WILL BE POSSIBLE.
   
   DISCUSSION...RECENT WATER VAPOR IMAGERY INDICATES A MID-LEVEL
   CYCLONE OVER THE UPPER MIDWEST -- SHEARED NE TO SW -- CENTERED OVER
   SRN MN. E/NE OF THE CYCLONE CENTER...STRONG ASCENT IN THE EXIT
   REGION OF A MID-LEVEL JET MAX ALIGNING WITH THE APEX OF A DRY SLOT
   IS BEING SUPPORTED BY AMPLE DCVA ACROSS NWRN WI INTO THE MN
   ARROWHEAD. STRONG ASCENT CURLS AROUND THE CYCLONE ACROSS ERN MN
   WITHIN THE COLD CONVEYOR BELT OF THE SYSTEM...WHERE LOW-TO-MID-LEVEL
   FRONTOGENETIC CIRCULATIONS ARE PRESENT WITHIN THE DEFORMATION ZONE
   OF THE CYCLONE.
   
   THE 00Z MPX RAOB SUGGESTS SUB-FREEZING TEMPERATURES THROUGHOUT THE
   TROPOSPHERE THAT WILL SUPPORT SNOW. REDUCED STATIC STABILITY BELOW
   THE 850-MB LEVEL AND IN THE MID-LEVELS MAY SUPPORT WEAK CONVECTIVE
   ENHANCEMENTS TO SNOWFALL RATES...WITH MODERATE TO HEAVY SNOW
   ANTICIPATED ACROSS THE AREA. SNOW RATES OF 1 IN/HR WILL BE POSSIBLE.
   THE AREA OF STRONGEST ASCENT LIES ACROSS NERN MN AND NWRN WI...WHERE
   OVERLAP OF AT LEAST MODEST MAGNITUDES OF LOW/MID-LEVEL FRONTOGENESIS
   AND DCVA EXISTS. SNOWFALL RATES OF 1 IN/HR WILL BE MOST LIKELY IN
   THIS AREA. THE SHIELD OF SNOW WILL ADVANCE NEWD DURING THE EVENING
   HOURS...TAPERING OFF FROM SW TO NE OVERNIGHT...IN CONCERT WITH
   MOTION OF THE MID-LEVEL CYCLONE.
   
   ..COHEN.. 04/19/2013
   
   
   ATTN...WFO...DLH...MPX...
   
   LAT...LON   48239101 48068990 47848978 47609067 46919183 46709186
               46939085 46629056 46119217 44779337 44879452 46059418
               47459302 48079188 48239101