

197 

WWUS20 KWNS 292144

SEL4

SPC WW 292144

MTZ000-300300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 574

NWS STORM PREDICTION CENTER NORMAN OK

345 PM MDT WED JUN 29 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       LARGE PART OF CENTRAL MONTANA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 345 PM UNTIL

900 PM MDT.



HAIL TO 1 INCH 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 60 MILES NORTHEAST OF

HAVRE MONTANA TO 25 MILES SOUTHEAST OF HARLOWTON 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.



DISCUSSION...HIGH BASED THUNDERSTORMS ARE INCREASING IN NUMBER AND

INTENSITY EWD ACROSS NCENTRAL MT.  WITH VERY STEEP LAPSE RATES AND

40-50KT OF SHEAR...DAMAGING DOWNBURSTS WINDS WILL BE COMMON WITH

STRONGEST STORMS AS THEY MOVE NEWD ACROSS THE WATCH AREA.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION

VECTOR 23040.





...HALES

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