MESOSCALE DISCUSSION 1406
   NWS STORM PREDICTION CENTER NORMAN OK
   0317 PM CDT THU JUL 02 2009
   
   AREAS AFFECTED...MT...WY...SD...NE
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 538...
   
   VALID 022017Z - 022145Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 538
   CONTINUES.
   
   A NEW WATCH MAY BE NEEDED TO THE SOUTH OF EXISTING SVR TSTM WATCH
   538 WITHIN A FEW HOURS. MEANWHILE...SEVERE WEATHER POTENTIAL
   CONTINUES ACROSS PARTS OF SERN MT...NERN WY AND ADJACENT PORTIONS OF
   WRN SD.
   
   RELATIVELY WEAK SYNOPTIC SCALE FORCING AND LIMITED SHEAR ACROSS MUCH
   OF THE REGION ARE LEADING TO DIFFICULT FORECAST SCENARIO THROUGH THE
   REST OF THE AFTERNOON. AN AXIS OF MODEST INSTABILITY /MLCAPE AROUND
   1000 J PER KG/ EXISTS ACROSS PORTIONS OF SERN MT AND WRN SD...AND
   EXTENDS SWD ACROSS THE NEB PNHDL. STORM DEVELOPMENT IN THE PAST FEW
   HOURS APPEARS TO HAVE BEEN TIED PRIMARILY TO TERRAIN/OROGRAPHIC
   INFLUENCES WITH LOW LEVEL UPSLOPE FLOW AND WEAK INHIBITION LEADING
   TO CONVECTIVE INITIATION. AN INCREASE IN DEEP-LAYER EFFECTIVE SHEAR
   AND ADDITIONAL DEVELOPMENT APPEARS UNDERWAY AS MID LEVEL
   IMPULSE/SPEED MAX SPREADS EAST FROM NRN WY OVER THE NEXT FEW HOURS.
   
   ADDITIONALLY...CHANCES FOR AT LEAST ISOLATED SEVERE STORM
   DEVELOPMENT MAY INCREASE IN SERN WY AND ADJACENT WRN NEB THROUGH THE
   EVENING AS WY SHORT WAVE TROUGH AND DIURNAL DESTABILIZATION
   CONTRIBUTE TO POTENTIAL INITIATION. MODEST SHEAR IS ALREADY IN PLACE
   THIS AREA WITH LOW LEVEL ELY WINDS TOPPED BY ABOUT 20-25KT WLY FLOW
   IN THE MID LEVELS. IF STORMS APPEAR MORE LIKELY...A NEW WATCH MAY BE
   NEEDED.
   
   ..CARBIN.. 07/02/2009
   
   
   ATTN...WFO...LBF...UNR...CYS...BYZ...GGW...RIW...
   
   LAT...LON   47470799 47220623 47230527 47340413 45890411 45880291
               44550198 43040199 41020195 41020493 43450500 43460546
               43500705 44470726 45530805 46110747 47470799