MESOSCALE DISCUSSION 1782
   NWS STORM PREDICTION CENTER NORMAN OK
   1137 PM CDT TUE AUG 04 2009
   
   AREAS AFFECTED...PORTIONS SWRN AND EXTREME S-CENTRAL SD...NWRN
   THROUGH CENTRAL NEB.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 660...662...
   
   VALID 050437Z - 050600Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   660...662...CONTINUES.
   
   WW 662 SHOULD BE CONTINUED UNTIL PASSAGE OF ZONE OF STRONGEST
   NEAR-SFC FLOW BEHIND LEADING EDGE OF MCS.  WW 660 IS SCHEDULED TO
   EXPIRE AT 05Z...AND LIKEWISE CAN BE CLEARED IN MEANTIME AS
   CONVECTIVE/KINEMATIC TRENDS WARRANT.  SVR TSTM THREAT MAY EXTEND SE
   OF WW 662 DURING 08Z-10Z TIME FRAME.  CONVECTIVE TRENDS WILL BE
   MONITORED DURING NEXT 2-3 HOURS FOR POSSIBILITY OF ADDITIONAL WW.
   
   MCS WITH LONG HISTORY OF SVR WIND...AND WELL-DEVELOPED COLD
   POOL...SHOULD TURN SOMEWHAT MORE SEWD ACROSS NWRN INTO CENTRAL NEB
   DURING NEXT FEW HOURS.  VERY STG PRESSURE PERTURBATION IS ANALYZED
   WITH COLD POOL -- I.E. 6-9 MB PER 2 HR RISES INVOF CDR.  54 KT GUST
   WAS MEASURED AT CDR AT 0316Z FROM TAIL-END ACTIVITY IN THIS
   COMPLEX...WHICH ALSO MAY CARRY THREAT FOR TRANSIENT SUPERCELL
   STRUCTURES WITH LARGE HAIL.  COMPLEX SHOULD CONTINUE TO POSE PRIMARY
   RISK FOR DAMAGING WIND CLOSE TO SFC MOIST AXIS AND LLJ...BUT SW OF
   SFC-850 MB MOISTURE GRADIENT...EACH OF WHICH WAS EVIDENT IN PARALLEL
   FROM PORTIONS CHERRY COUNTY NEB SEWD ACROSS CENTRAL NEB.  NEW BOW
   ECHO ALSO MAY EVOLVE FROM NEWER/SVR CONVECTION CLOSER TO SRN PORTION
   OF CURRENT COMPLEX...AND MOVE SEWD TOWARD BBW AREA.  IN ADDITION TO
   FORWARD-PROPAGATION ALONG COLD POOL...FCST MOISTURE
   FIELDS...EXPECTED VEERING OF LLJ NEAR TAIL END OF COMPLEX...AND
   RESULTING ADJUSTMENT OF REAR-PROPAGATIONAL MCS MOTION VECTORS...ALSO
   SUGGEST SOME BACKBUILDING COMPONENT POSSIBLY AFFECTING LBF AREA. 
   INFLOW-LAYER MOISTURE CONTENT AND BUOYANCY...AS WELL AS
   STORM-RELATIVE LOW LEVEL FLOW...EACH WILL BE MAXIMIZED ROUGHLY ALONG
   AXIS FROM TIF-BBW-HSI.  KINEMATIC PROFILES WILL REMAIN
   FAVORABLE...WITH 50-60 KT EFFECTIVE SHEAR VECTORS ALIGNED NEARLY
   NORMAL TO PROJECTED MCS MOTION.  MAIN LIMITING FACTOR WILL BE
   INCREASING DEPTH OF NEAR-SFC STABLE LAYER DUE TO DIABATIC
   COOLING...AND RESULTANT REDUCTION IN MLCAPE AND DCAPE. 
   HOWEVER...STG-SVR GUSTS SHOULD CONTINUE TO PENETRATE TO SFC GIVEN
   ROBUST ORGANIZATION OF COLD POOL.
   
   ..EDWARDS.. 08/05/2009
   
   
   ATTN...WFO...OAX...GID...LBF...UNR...CYS...
   
   LAT...LON   43740121 41839731 40509764 40619964 42580301 43000188
               43290138 43740121