

200 

WWUS20 KWNS 132159

SEL1

SPC WW 132159

MTZ000-WYZ000-140600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 701

NWS STORM PREDICTION CENTER NORMAN OK

400 PM MDT THU AUG 13 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL MONTANA

       NORTH CENTRAL WYOMING



EFFECTIVE THIS THURSDAY AFTERNOON FROM 400 PM UNTIL MIDNIGHT 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 105

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES NORTH

NORTHWEST OF BUTTE MONTANA TO 65 MILES NORTH NORTHEAST OF

BILLINGS 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.



DISCUSSION...THUNDERSTORMS CONTINUE TO DEVELOP ACROSS WESTERN MT

AHEAD OF AN APPROACHING UPPER TROUGH.  THESE STORMS ARE EXPECTED TO

INCREASE IN COVERAGE THIS EVENING WITH SCATTERED STORMS BECOMING

LOCALLY SEVERE.  40-50 KNOTS OF EFFECTIVE SHEAR AND

NORTHEASTERLY/UPSLOPE LOW LEVEL WINDS SUGGEST THAT A FEW SUPERCELLS

ARE POSSIBLE CAPABLE OF DAMAGING WINDS AND LARGE HAIL.



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 450. MEAN STORM

MOTION VECTOR 25035.





...HART

