MESOSCALE DISCUSSION 1737
   NWS STORM PREDICTION CENTER NORMAN OK
   0733 PM CDT SUN AUG 18 2013

   AREAS AFFECTED...NWRN MN/SERN ND/NCNTRL SD

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 190033Z - 190200Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...ISOLATED SEVERE TSTMS ARE EXPECTED ALONG PRE-FRONTAL WIND
   SHIFT ACROSS MN/ND/SD.  THIS ACTIVITY SHOULD PROVE TOO SPARSE TO
   WARRANT A WATCH.

   DISCUSSION...LEAD SHORT-WAVE TROUGH OVER WRN ONTARIO IS MOSTLY
   RESPONSIBLE FOR VEERED LOW LEVEL FLOW AND PRE-FRONTAL WIND SHIFT
   ACROSS THE RED RIVER VALLEY.  PRIMARY FRONTAL SURGE IS MORE EVIDENT
   WITH SECONDARY SHORT-WAVE TROUGH LOCATED OVER MB/ND.  OVER THE LAST
   HOUR OR SO A LONE SEVERE TSTM HAS DEVELOPED ALONG THE PRE-FRONTAL
   WIND SHIFT OVER MARSHALL COUNTY MN.  EVEN SO...NEW CONVECTION MAY
   STRUGGLE TO EVOLVE GIVEN THAT STRONGER FORCING REMAINS CONSIDERABLY
   UPSTREAM ACROSS ND.  00Z SOUNDINGS FROM THIS REGION EXHIBIT STEEP
   LAPSE RATES BUT VERY STRONG MID LEVEL CAPPING CURRENTLY RESIDES
   ACROSS NRN SD...PER ABR PROFILE.  LATEST THINKING IS LARGE SCALE
   FORCING MAY RESULT IN MOST SUBSTANTIAL CONVECTION REMAINING
   POST-FRONTAL AND ONLY VERY ISOLATED ACTIVITY ACTUALLY EVOLVING ALONG
   THE SFC WIND SHIFT WHERE HIGHER MOISTURE/BUOYANCY RESIDES.  LARGE
   HAIL LIKELY ACCOMPANIES THE NWRN MN STORM AND THIS IS THE PRIMARY
   SEVERE THREAT WITH STORMS THAT MANAGE TO MATURE NEAR THE HIGHER
   QUALITY INSTABILITY.  GIVEN THE SPARSE COVERAGE DO NOT ANTICIPATE
   SEVERE THUNDERSTORM WATCH AT THIS TIME.

   ..DARROW/MEAD.. 08/19/2013


   ATTN...WFO...FGF...ABR...BIS...

   LAT...LON   45380044 46570002 47039829 48039725 48959620 48559464
               46479699 45169902 45380044