MESOSCALE DISCUSSION 1398
   NWS STORM PREDICTION CENTER NORMAN OK
   1044 AM CDT SUN JUN 26 2011
   
   AREAS AFFECTED...PORTIONS SRN SD AND NRN/WRN NEB.
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 261544Z - 261745Z
   
   BAND OF TSTMS HAS DEVELOPED ALONG INITIALLY QUASISTATIONARY FRONTAL
   ZONE FROM SWRN SD TO NRN PANHANDLE OF NEB...WITH MORE ISOLATED
   ACTIVITY INTERMITTENTLY FORMING FARTHER SE OVER NEB SANDHILLS. 
   WHILE INITIALLY ELEVATED...ACTIVITY MAY BACKBUILD AND/OR TRANSLATE
   INTO MORE FAVORABLE SFC-BASED BUOYANCY...INCREASING POTENTIAL FOR
   ORGANIZED SVR.  QUICK TRANSITION ALREADY EVIDENT TO LINEAR MODE
   SUGGESTS DAMAGING GUSTS AS MAIN CONCERN.  HOWEVER...FAVORABLE
   VERTICAL SHEAR PROFILES DO SUPPORT SUPERCELL POTENTIAL WITH ANY
   SUSTAINED/DISCRETE ACTIVITY AHEAD OF LINE OR ANY PERSISTENT ANCHOR
   STORM ON SRN END OF COMPLEX.
   
   SFC MESOANALYSIS SHOWS FRONTAL ZONE FROM SERN ND TO NEAR
   ABR-PIR-IEN-BFF-CYS LINE...CONNECTED OVER SWRN PANHANDLE TO SFC
   TROUGH EXTENDING SWWD TO LOW NNE DEN.  ONGOING/BACKBUILDING
   CONVECTION ALONG FRONT MAY DEVELOP COLD POOL...WHICH WOULD SHUNT
   EFFECTIVE FRONTAL ZONE SEWD AND ALSO INCREASE POTENTIAL FOR
   ORGANIZED DAMAGING WIND EVENT ACROSS SRN SD SWD OVER SANDHILLS
   REGION OF NEB.  ONGOING ACTIVITY IS NOT RESOLVED WELL BY SHORT-RANGE
   MODELS...INCLUDING HRRR AND FINE-SCALE/CONVECTION-ALLOWING VERSIONS
   OF WRF...WHICH APPEAR NOT TO RESOLVE STRENGTH/CHARACTER OF
   BAROCLINIC ZONE WELL.  CURRENTLY CAPPING INCREASES SUBSTANTIALLY
   WITH EWD EXTENT...AND EARLIER TSTMS THAT FORMED IN GENERALLY SAME
   REGION HAVE DISSIPATED OR WEAKENED MARKEDLY. HOWEVER...MODIFIED
   RAOBS AND RUC SOUNDINGS INDICATE STG CINH EVIDENT IN 12Z LBF RAOB IS
   CONSIDERABLY WEAKER FARTHER NW ACROSS SANDHILLS...SRN SD AND MUCH OF
   NEB PANHANDLE...WITH ADDITIONAL SFC DIABATIC HEATING LIKELY TO
   ENLARGE AREA OF FAVORABLE BOUNDARY-LAYER BUOYANCY THROUGH REMAINDER
   MORNING.  MOIST ADVECTION/TRANSPORT RELATED TO SFC-850 MB
   SELYS...NEAR NRN BRANCH LLJ...WILL BOOST POTENTIAL FURTHER.  MLCAPE
   1500-2500 J/KG SHOULD CHARACTERIZE PREFRONTAL CORRIDOR...AMIDST
   40-50 KT EFFECTIVE SHEAR MAGNITUDE AND 200-400 J/KG EFFECTIVE SRH.
   
   ..EDWARDS.. 06/26/2011
   
   
   ATTN...WFO...FSD...ABR...LBF...UNR...CYS...
   
   LAT...LON   42450296 43420213 43970156 43820036 43549949 42999941
               41870026 41650209 41880282 42390304 42450296