WATCHES: Severe Thunderstorm Watch Number 438

WWUS20 KWNS 021944
SEL8
SPC WW 021944
MTZ000-030500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 438
NWS STORM PREDICTION CENTER NORMAN OK
140 PM MDT FRI JUL 2 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND NORTHEAST MONTANA

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 140 PM UNTIL
1100 PM MDT.

HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 100
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH
NORTHEAST OF GLASGOW MONTANA TO 55 MILES SOUTH SOUTHEAST OF
LIVINGSTON MONTANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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.

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THIS AFTERNOON AS A COLD FRONT MOVES EAST ACROSS CENTRAL
AND NORTHEAST MT. VERY WARM AND UNSTABLE CONDITIONS AHEAD OF THE
FRONT WILL FOSTER ROBUST AND LONG-LIVED THUNDERSTORMS. GIVEN
STRENGTHENING MID LEVEL FLOW OF UP TO 50KT...EXPECT STORMS TO BE
WELL ORGANIZED AND INCLUDE SUPERCELLS...WITH THE PROSPECT OF LARGE
HAIL...AS WELL AS LINE SEGMENTS CAPABLE OF PRODUCING LOCALLY
DAMAGING WIND GUSTS.
CONVECTION WAS ALREADY INITIATING ACROSS THE HIGHER TERRAIN OF
SOUTHWEST MT WHERE OROGRAPHIC AND FRONTAL LIFT HAVE OVERCOME
INHIBITION. EXPECT ADDITIONAL DEVELOPMENT NEXT FEW HOURS AS THE
FRONT MOVES INTO CENTRAL MT. DRIER AIRMASS EMANATING FROM WY...MAY
INHIBIT DEVELOPMENT ACROSS SOUTH-CENTRAL MT. HOWEVER...ANY STORMS
MOVING ACROSS THIS AREA LATER WILL POSE SOME THREAT FOR DAMAGING
WINDS GIVEN DEEPLY MIXED AND HOT BOUNDARY LAYER AIRMASS EXPECTED.
ADDITIONAL...PERHAPS LINEAR DEVELOPMENT...MAY OCCUR LATER TODAY AND
INTO TONIGHT AS THE COLD FRONT MOVES INTO NERN MT. SOME GUIDANCE
SUGGESTS STORM MAY ACTUALLY FORM IMMEDIATELY BEHIND THE FRONTAL WIND
SHIFT. NONETHELESS...THIS ACTIVITY COULD STILL PRODUCE HAIL AND
GUSTY WINDS IN THESE AREAS THROUGH THE EVENING.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 24030.

...CARBIN

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