SEVERE THUNDERSTORM WATCH NUMBER 354

   SEL4          URGENT - IMMEDIATE BROADCAST REQUESTED     SEVERE THUNDERSTORM WATCH NUMBER 354     NWS STORM PREDICTION CENTER NORMAN OK     430 PM MDT MON JUN 4 2012          THE NWS STORM PREDICTION CENTER HAS ISSUED A     SEVERE THUNDERSTORM WATCH FOR PORTIONS OF                  CENTRAL AND SOUTHERN MONTANA          EFFECTIVE THIS MONDAY AFTERNOON AND TUESDAY MORNING FROM 430 PM     UNTIL 100 AM MDT.          HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75     MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.          THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 105     STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTHWEST OF     HAVRE MONTANA TO 25 MILES EAST SOUTHEAST OF DILLON MONTANA.  FOR     A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH     OUTLINE UPDATE (WOUS64 KWNS WOU4).          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 352...WW 353...          DISCUSSION...SCTD STRONG TSTMS...INCLUDING ONE OR TWO DEVELOPING     SUPERCELLS...HAVE FORMED OVER THE WRN MT MOUNTAINS IN STRENGTHENING     SSW FLOW DOWNSTREAM FROM POTENT/AMPLIFYING SHORTWAVE TROUGH OVER     CA/ORE.  COMBINATION OF INCREASING WIND FIELD/LARGE SCALE FORCING     FOR ASCENT...CONTINUED SFC HEATING...AND ESELY LOW LVL MOISTURE     INFLOW SUGGEST THAT STORMS LIKELY WILL INCREASE IN NUMBER AND     STRENGTH E OF THE MOUNTAINS.  THE ACTIVITY MAY EVOLVE INTO ONE OR     TWO SUSTAINED CLUSTERS.  EMBEDDED SUPERCELLS IN THESE SYSTEMS WILL     BE CAPABLE OF HIGH WIND AND LARGE HAIL.  WITH TIME...THE THREAT FOR     TORNADOES MAY INCREASE AS THE STORMS ENCOUNTER AN INCREASINGLY     MOIST/MORE STRONGLY SHEARED LOW LVL ENVIRONMENT.  THIS MAY REQUIRE     PARTIAL UPGRADE OF THE SVR WATCH TO A TORNADO WATCH...ESPECIALLY     ACROSS N CNTRL MT.     FARTHER SE...A SEPARATE AREA OF TSTMS IS EXPECTED TO CONTINUE     MOVING/DEVELOPING NNE FROM THE MOUNTAINS OF NRN WY/S CNTRL MT.      WHILE DEEP SHEAR WILL REMAIN WEAKER THERE RELATIVE TO POINTS FARTHER     N/W...IT WILL BE SUFFICIENT FOR SOME ORGANIZED/POSSIBLY SVR STORMS     THROUGH LATER TNGT.          AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT     TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65     KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM     MOTION VECTOR 21035.