MESOSCALE DISCUSSION 1556
   NWS STORM PREDICTION CENTER NORMAN OK
   0103 AM CDT SUN JUL 10 2011
   
   AREAS AFFECTED...PORTIONS SERN SD...NERN NEB...SWRN MN...NWRN IA.
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 100603Z - 100800Z
   
   CLUSTER OF TSTMS MAY CONTINUE TO POSE RISK OF OCNL LARGE HAIL AS IT
   MOVES GENERALLY ESEWD/SEWD TOWARD SWRN MN AND NERN IA. 
   HOWEVER...ACTIVITY SHOULD EVOLVE INTO MORE OF A SHORT-LIVED SVR WIND
   THREAT THROUGH ABOUT 08Z.
   
   SFC MESOANALYSIS SHOWS QUASISTATIONARY PRE-FRONTAL TROUGH EXTENDING
   SWWD FROM LOW IN W-CENTRAL MN...THROUGH BAND OF CONVECTION OVER
   BROOKINGS/MOODY/LAKE/MINNEHAHA/COOK COUNTIES SD...THEN OVER NEB
   SANDHILLS.  LOW-LEVEL CONVERGENCE NEAR THIS TROUGH APPEARS
   RESPONSIBLE FOR INITIATING EXISTING ACTIVITY.  MODIFIED RUC
   SOUNDINGS SUGGEST RELATIVE MIN IN CAPPING OVER DISCUSSION
   AREA...WITH LOW-MID 70S F SFC DEW POINTS CONTRIBUTING TO MLCAPE NEAR
   3000 J/KG...AMIDST FAVORABLE EFFECTIVE SHEAR MAGNITUDES AROUND 40-45
   KT.  ACTIVITY MAY WEAKEN OVER MN/IA BORDER REGION E OF SD AS IT
   MOVES INTO PROGRESSIVELY SMALLER NEAR-SFC THETAE...AND BECOMES MORE
   OUTFLOW-DOMINANT WITH GUST FRONT POTENTIALLY OUTRUNNING HIGHER
   REFLECTIVITIES.  THOUGH MLCINH IS INCREASING WITH TIME DUE TO
   DIABATIC SFC COOLING...ADDITIONAL CONVECTION MAY DEVELOP WHERE
   OUTFLOW BOUNDARY FROM SWRN NEB CONVECTION OVERTAKES SFC TROUGH FROM
   ANW AREA NEWD TO NEAR SD/NEB BORDER AS WELL.  LONG-LIVED OR
   WELL-ORGANIZED SVR POTENTIAL IS LIMITED FOR HAIL BY LESS
   DISCRETE/MORE MESSY CONVECTIVE MODE...AND FOR WIND BY LACK OF
   SUPPORT FOR EVAPORATIONAL COLD-POOL ENHANCEMENT IN VERY RICHLY MOIST
   AND SLOWLY-COOLING BOUNDARY LAYER.
   
   ..EDWARDS.. 07/10/2011
   
   
   ATTN...WFO...MPX...DMX...FSD...OAX...ABR...LBF...
   
   LAT...LON   42599980 43759760 44729636 44509485 43899378 43279386
               42969490 42919653 42399818 42209939 42389967 42599980