MESOSCALE DISCUSSION 1656
   NWS STORM PREDICTION CENTER NORMAN OK
   0456 PM CDT SUN JUL 06 2003
   
   AREAS AFFECTED...MUCH OF ERN SD...PARTS OF SW MN
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 062156Z - 070000Z
   
   WIDELY SCATTERED TSTMS MAY DEVELOP NEXT 2-3 HOURS ACROSS PORTIONS
   NERN SD AHEAD OF SFC COLD FRONT...IN ADDITION TO BACKBUILDING ALONG
   FRONT FROM ND. PRIMARY THREATS WILL BE DAMAGING HAIL/WIND...A FEW
   TORNADOES POSSIBLE.  WW MAY BE REQUIRED NEXT 1-2 HOURS. 
   
   SFC MESOANALYSIS SHOWS COLD FRONT ACROSS NWRN MN AND ND...PARALLEL
   TO AND ABOUT 75 NM W OF WW 656...THEN SWWD ACROSS MBG/PHP/CDR AREAS.
    FRONTAL CONVERGENCE WILL REMAIN LIMITED NEXT 2-3 HOURS BY NLY
   COMPONENT OF SFC FLOW BETWEEN FRONT AND PREFRONTAL TROUGH -- FROM
   WRN PORTION WW 656 THROUGH HON-ANW LINE.  BOTH FEATURES SHOULD MOVE
   EWD/SEWD 15-20 KT.  ISALLOBARIC FORCING MAY RESULT IN SOME TURNING
   OF LOW LEVEL FLOW AND INCREASE IN CONVERGENCE ALONG FRONT OVER NERN
   SD.  MEANWHILE...CAP IS WEAKENING IN WARM SECTOR ACROSS NERN SD NEAR
   PREFRONTAL TROUGH...WITH TCU AND NASCENT CB BETWEEN ATY-ABR. 
   MODIFIED RAOBS AND RUC FCST SOUNDINGS INDICATE VERY UNSTABLE AIR
   MASS...WITH UPPER 60S/70S F DEW POINTS SPREADING NEWD BENEATH
   ROUGHLY 8 DEG C/KM MIDLEVEL LAPSE RATES...CONTRIBUTING TO MLCAPE
   AROUND 3000 J/KG.  INITIALLY WEAK LOW LEVEL FLOW/SHEAR SHOULD
   STRENGTHEN THROUGH EVENING WITH APPROACH OF MIDLEVEL TROUGH NOW OVER
   SWRN AND N-CENTRAL ND...ENLARGING HODOGRAPHS AND FURTHER SUPPORTING
   SEVERE POTENTIAL.  
   0-6 KM AGL SHEAR SHOULD STRENGTHEN TO 50-60 KT RANGE.
   
   ..EDWARDS.. 07/06/2003
   
   
   ATTN...WFO...DLH...MPX...FGF...FSD...ABR...
   
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