MESOSCALE DISCUSSION 1522
   NWS STORM PREDICTION CENTER NORMAN OK
   0125 PM CDT WED JUL 06 2011
   
   AREAS AFFECTED...WRN ND...WRN SD...NWRN NEB
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 061825Z - 062100Z
   
   CONVECTIVE TRENDS WILL BE MONITORED FOR THE POSSIBLE ISSUANCE OF A
   WW OR WWS INTO THE AFTERNOON.
   
   ASCENT PROVIDED BY A SUBTLE SHORTWAVE TROUGH PROGRESSING THROUGH
   WLY/WNWLY MID-LEVEL FLOW IS RESPONSIBLE FOR MAINTAINING AREAS OF
   CONVECTION OVER PORTIONS OF THE WRN DAKOTAS. THE EXACT EVOLUTION OF
   THIS ACTIVITY IS UNCERTAIN OWING TO THE ABSENCE OF STRONGER / MORE
   FOCUSED FORCING MECHANISMS. HOWEVER...WITH POCKETS OF MLCAPE ALREADY
   REACHING 2000 J/KG...AND ADDITIONAL DESTABILIZATION ANTICIPATED
   OWING TO DIABATIC HEATING PROCESSES...INTENSIFICATION OF ONGOING
   CONVECTION AND/OR DEVELOPMENT OF NEW CONVECTION APPEAR POSSIBLE.
   
   ONGOING CONVECTION INCLUDES A DISORGANIZED MULTICELLULAR CLUSTER
   OCCASIONALLY EVOLVING INTO A MORE LINEAR CONVECTIVE SYSTEM OVER SWRN
   SD. A MODERATELY UNSTABLE AIR MASS LEADING THIS FEATURE COULD
   SUPPORT CONTINUED FORWARD PROPAGATION INTO S-CNTRL SD...AND A THREAT
   FOR DMGG SFC WINDS COULD INCREASE AS LOW-LEVEL LAPSE RATES
   STEEPEN...PARTICULARLY IF THE SYSTEM MAINTAINS ORGANIZATION. WLY
   FLOW AROUND 25 KT IN THE MID-LEVELS PER RAPID CITY VWP COULD SUPPORT
   SUFFICIENT VERTICAL SHEAR FOR THIS TO OCCUR. HOWEVER...SHOULD IT
   CROSS A SFC FRONT DRAPED ACROSS PORTIONS OF THE ERN DAKOTAS INTO WRN
   MN AND BECOME INCREASINGLY ELEVATED...THIS THREAT COULD SUBSIDE.
   REGARDLESS...ADDITIONAL CLUSTERS OF CONVECTION OVER ITS SRN FLANK
   COULD INTENSIFY WITH TIME AND POSE AN ISOLATED SVR THREAT INTO THE
   AFTERNOON AND POTENTIALLY IMPACT PORTIONS OF NWRN NEB...AS DEPICTED
   IN THE 15Z RUN OF THE EXPERIMENTAL HRRR.
   
   FARTHER NORTH ACROSS WRN ND...A SFC CONFLUENCE AXIS IS BEING
   MAINTAINED BY THE PERSISTENT ELY COMPONENT OF THE LOW-LEVEL FLOW.
   THIS IS THE RESULT OF THE COLD POOL ATTENDANT TO SCATTERED
   PRECIPITATION CNTRL SD. MOISTURE CONVERGENCE ALONG THE CONFLUENCE
   AXIS...AND ALONG A SFC TROUGH EXTENDING S/SW FROM A LOW OVER NERN
   MT...COULD BE FOCI FOR ADDITIONAL CONVECTION INTO THE AFTERNOON.
   SUFFICIENT VERTICAL SHEAR COULD SUPPORT MULTICELLULAR
   CLUSTERS...WITH DMGG WINDS AND LARGE HAIL THE MAIN CONCERNS.
   
   ..COHEN.. 07/06/2011
   
   
   ATTN...WFO...ABR...BIS...LBF...UNR...CYS...
   
   LAT...LON   47030384 48230304 48640178 48620071 48390001 47219990
               45900004 44070029 43120076 42550174 42800332 44400390
               47030384