MESOSCALE DISCUSSION 1507
   NWS STORM PREDICTION CENTER NORMAN OK
   1114 PM CDT MON JUL 04 2011
   
   AREAS AFFECTED...PORTIONS SD...N-CENTRAL/NERN NEB.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 597...
   
   VALID 050414Z - 050545Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 597
   CONTINUES.
   
   CLUSTER OF STG-SVR TSTMS FROM CENTRAL SD SWD ACROSS CHERRY COUNTY
   NEB MAY DEVELOP AGGREGATE COLD POOL...LEADING TO SLAB OF FORCED
   ASCENT TO LFC AND POTENTIAL EXTENSION OF DAMAGING WIND POTENTIAL EWD
   FROM CURRENT WW AREA ACROSS PORTIONS NERN NEB AND SERN SD. 
   OFFSETTING FACTOR WILL BE STABILIZATION OF BOUNDARY LAYER WITH TIME
   DUE TO DIABATIC SFC COOLING...AND WITH EWD EXTENT GIVEN LOWER
   ANTECEDENT THETAE.  CONVECTIVE TRENDS WILL BE MONITORED ACCORDINGLY
   FOR POSSIBLE EXTENSION OF EXISTING WW...OR NEW WW ACROSS THOSE
   AREAS.
   
   MEANWHILE ISOLATED SUPERCELL INVOF ABR WILL CONTINUE TO POSE THREAT
   FOR DAMAGING HAIL/GUSTS...AND PERHAPS A TORNADO...BEFORE
   ENCOUNTERING BOTH INCREASING WARM-SECTOR CAPPING AND COLD FRONT
   MOVING INTO AREA FROM SERN ND AND N-CENTRAL SD.  SOME POTENTIAL
   REMAINS FOR INITIALLY ACTIVITY TO BACKBUILD ALONG FRONT AS SWWD
   EXTENSION OF MATURE MCS OVER WW 598...REF SPC MESOSCALE DISCUSSION
   1506 FOR MORE DETAILS ON THAT REGIME.  FCST SOUNDINGS AND MODIFIED
   ABR RAOB SUGGEST CHANNEL OF RELATIVELY WEAKENED CINH AND MLCAPE
   2000-3000 J/KG JUST AHEAD OF COLD FRONT....HOWEVER BUOYANCY WILL
   DIMINISH AND CINH WILL INCREASE IN PREFRONTAL ENVIRONMENT AS
   BOUNDARY PROCEEDS SEWD.
   
   ..EDWARDS.. 07/05/2011
   
   
   ATTN...WFO...FSD...OAX...ABR...LBF...UNR...
   
   LAT...LON   43040102 44530131 45859910 45759677 43259725 42099890
               42090054 43040102