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WWUS20 KWNS 172045

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SPC WW 172045

MTZ000-WYZ000-180400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 491

NWS STORM PREDICTION CENTER NORMAN OK

245 PM MDT MON AUG 17 2015



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHEASTERN MONTANA

  EASTERN WYOMING



* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

  1000 PM MDT.



* PRIMARY THREATS INCLUDE...

  SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER LIKELY

  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A TORNADO OR TWO POSSIBLE



SUMMARY...SCATTERED THUNDERSTORMS EXPECTED TO INCREASE AND DEVELOP

GENERALLY EAST-SOUTHEAST ACROSS WATCH AREA THROUGH LATE EVENING. A

FEW LONGER-LIVED SUPERCELLS MAY OCCUR THAT WILL BE CAPABLE OF SEVERE

HAIL...LOCALLY DAMAGING WIND...AND POSSIBLY A COUPLE TORNADOES.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES EAST AND WEST OF A LINE FROM 75 MILES NORTHWEST OF

BROADUS MONTANA TO 25 MILES SOUTH SOUTHWEST OF DOUGLAS WYOMING.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 490...



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 29030.





...CORFIDI

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