MESOSCALE DISCUSSION 0964
   NWS STORM PREDICTION CENTER NORMAN OK
   0633 PM CDT WED MAY 21 2008
   
   AREAS AFFECTED...ERN WY/PARTS OF ERN CO/NEB PANHANDLE AND FAR SWRN
   SD
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 333...
   
   VALID 212333Z - 220030Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 333
   CONTINUES.
   
   STORMS PRODUCING HAIL AND STRONG WIND GUSTS REMAIN LIKELY ACROSS WW
   333 INTO THE EARLY EVENING.
   
   MESOSCALE ANALYSIS SHOWED A LOW PRESSURE AREA OVER SERN WY /NERN
   CARBON COUNTY/ WITH A ZONE OF CONVERGENCE/BOUNDARY EXTENDING NNWWD
   INTO NRN WY AND ALSO SSEWD FROM THE LOW INTO NERN CO.  CONVERGENCE
   ALONG THIS BOUNDARY AND ALSO ALONG CONVECTIVE OUTFLOW BOUNDARIES
   WILL REMAIN THE FOCI FOR NEW TSTM DEVELOPMENT INTO THE EVENING. 
   STEEP LAPSE RATE ENVIRONMENT EXTENDING EWD INTO THE CENTRAL HIGH
   PLAINS WITH MODERATE INSTABILITY AND 40-50 KT OF EFFECTIVE BULK
   SHEAR LOCATED ALONG AND E OF THE SURFACE BOUNDARY REMAIN SUPPORTIVE
   OF SUSTAINED...ROTATING UPDRAFTS.
   
   FARTHER SWD ACROSS SERN CO...ASCENT AHEAD OF A SHORT WAVE TROUGH
   TRACKING NE TOWARD ERN CO/WRN KS COMBINED WITH LOW LEVEL UPSLOPE
   FLOW INTO THE HIGHER TERRAIN GENERALLY S OF PUB IS EXPECTED TO
   SUPPORT ADDITIONAL TSTM DEVELOPMENT.  THIS ACTIVITY...INITIALLY
   LOCATED WITHIN A WEAKLY UNSTABLE AIR MASS...WILL POSE A THREAT FOR
   ISOLATED STRONG WIND GUSTS GIVEN STEEP LOW LEVEL LAPSE RATES AND
   40-50 DEGREE SURFACE DEWPOINT DEPRESSIONS.  HOWEVER...THIS ACTIVITY
   SHOULD POSE A GREATER SEVERE RISK AS THESE STORMS TRACK NEWD INTO
   THE STRONGER INSTABILITY AXIS LOCATED IN THE VICINITY OF THE CO/KS
   BORDER.
   
   ..PETERS.. 05/21/2008
   
   
   ATTN...WFO...LBF...DDC...UNR...GLD...PUB...BOU...CYS...BYZ...RIW...
   
   37180469 38100454 39440505 41260590 42160666 43560767
   44120816 44540718 44990525 44960414 43940355 43010280
   41410232 40620190 38850171 38070209 37400348