SEVERE THUNDERSTORM WATCH FOR PORTIONS OF EASTERN MONTANA WESTERN NORTH DAKOTA NORTHWEST SOUTH DAKOTA NORTHEAST WYOMING EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 205 PM UNTIL 900 PM MDT

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 551
   NWS STORM PREDICTION CENTER NORMAN OK
   205 PM MDT THU AUG 2 2012
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          EASTERN MONTANA
          WESTERN NORTH DAKOTA
          NORTHWEST SOUTH DAKOTA
          NORTHEAST WYOMING
   
   EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 205 PM UNTIL
   900 PM MDT.
   
   HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85
   STATUTE MILES EAST AND WEST OF A LINE FROM 80 MILES EAST OF
   GILLETTE WYOMING TO 50 MILES NORTHEAST OF WOLF POINT MONTANA. 
   FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
   OUTLINE UPDATE (WOUS64 KWNS WOU1).
   
   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.
   
   OTHER WATCH INFORMATION...CONTINUE...WW 550...
   
   DISCUSSION...STORMS ARE INTENSIFYING OVER SERN MT AND NERN WY ALONG
   A DRY LINE/CONVERGENCE ZONE...WHILE NEW CU/TCU IS EVIDENT IN
   SATELLITE IMAGERY FARTHER NORTH INTO NERN MT WHERE LOW LEVEL
   MOISTURE WITH SURFACE DEW POINTS REMAIN IN THE 50S.  INITIAL ARC OF
   WARM ADVECTION CONVECTION FROM NERN MT INTO SWRN ND IS EXPECTED TO
   PROGRESS EWD WITH ADDITIONAL STRONG/SEVERE STORMS DEVELOPING OVER
   ERN MT AND NERN WY.  STEEP LAPSE RATES ARE CONTRIBUTING TO MLCAPE OF
   1000-1500 J/KG...AND 30-40 KT WESTERLY MID LEVEL WINDS ARE RESULTING
   IN SUFFICIENT DEEP LAYER SHEAR TO SUPPORT ORGANIZED SEVERE STORMS
   INTO THE EVENING HOURS AS ACTIVITY SPREADS EWD.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
   MOTION VECTOR 27025.