MESOSCALE DISCUSSION 2000
   NWS STORM PREDICTION CENTER NORMAN OK
   0232 PM CDT TUE SEP 08 2009
   
   AREAS AFFECTED...CNTRL SD...NW NEB
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 081932Z - 082100Z
   
   A SEVERE THREAT IS EXPECTED TO DEVELOP OVER THE NEXT 1 TO 2 HOURS AS
   STORMS INITIATE ACROSS CNTRL SD AND NW NEB. ISOLATED LARGE HAIL AND
   WIND DAMAGE WILL BE POSSIBLE WITH THE STRONGER CELLS. A WW WILL
   LIKELY BE NEEDED ACROSS THE AREA BY 20Z.
   
   19Z SFC ANALYSIS CURRENTLY SHOWS A WELL-DEFINED COLD FRONT EXTENDING
   FROM ERN ND SSWWD ACROSS CNTRL SD INTO NW NEB WITH A SFC LOW NEAR
   PIERRE SD. RUC ANALYSIS SUGGESTS THE CAP HAS WEAKENED OVER THE LAST
   HOUR ALONG THE FRONT IN SCNTRL SD AND THIS SHOULD ALLOW FOR
   CONVECTIVE INITIATION WHICH APPEARS TO BE OCCURRING ON VISIBLE
   SATELLITE IMAGERY. SHORT-TERM MODEL FORECASTS ARE IN AGREEMENT
   RAPIDLY EXPANDING STORM COVERAGE ACROSS THE MCD AREA AFTER 21Z. A
   MID-LEVEL JET EVIDENT ON WATER VAPOR IMAGERY AND ANALYZED BY THE RUC
   IS LOCATED ACROSS THE NRN HIGH PLAINS. THIS FEATURE IS HELPING TO
   CREATE MODERATE TO STRONG VERTICAL SHEAR PROFILES WHICH WILL MAKE
   ORGANIZED STORMS LIKELY. ISOLATED SUPERCELLS WILL BE POSSIBLE LATE
   THIS AFTERNOON BUT LINEAR DEVELOPMENT ALONG THE COLD FRONT SHOULD
   BECOME THE DOMINANT MODE WITH TIME. STEEP MID-LEVEL LAPSE RATES AND
   MODERATE INSTABILITY WILL SUPPORT A LARGE HAIL THREAT. LOW-LEVEL
   LAPSE RATES WILL CONTINUE TO STEEPEN AND LOW-LEVEL FLOW WILL
   INCREASE LATE THIS AFTERNOON INTO EARLY EVENING SUGGESTING A WIND
   DAMAGE THREAT SHOULD ALSO DEVELOP.
   
   ..BROYLES.. 09/08/2009
   
   
   ATTN...WFO...FSD...ABR...LBF...UNR...CYS...
   
   LAT...LON   43510153 42690215 42130275 41740286 41480263 41780164
               42300087 42900000 43849869 44649802 45189791 45579825
               45779865 45789919 45599966 44850038 44420079 43980117
               43510153