WWUS20 KWNS 042243
SEL4
SPC WW 042243
MTZ000-050700-

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.


...CORFIDI