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WWUS20 KWNS 172054

SEL9

SPC WW 172054

IDZ000-MTZ000-180400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 419

NWS STORM PREDICTION CENTER NORMAN OK

245 PM MDT WED JUL 17 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHERN AND EASTERN IDAHO

  WESTERN AND CENTRAL MONTANA



* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 245 PM

  UNTIL 1000 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 110

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST

SOUTHEAST OF DILLON MONTANA TO 40 MILES NORTHWEST OF CUT BANK

MONTANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 416...WW 417...WW 418...



DISCUSSION...TSTMS NOW FORMING OVER THE HIGHER TERRAIN OF CNTRL/NRN

ID AND WRN MT EXPECTED TO INCREASE AND MOVE/DEVELOP ENE OVER THE

NEXT SEVERAL HOURS AS HEATING CONTINUES ALONG SRN FRINGE OF UPR

IMPULSE MOVING NEWD INTO BC/AB. 40+ KT SWLY DEEP SHEAR AND PRESENCE

OF AMPLE LOW-LVL MOISTURE/LOW-LVL SSELY FLOW E OF THE MOUNTAINS

SHOULD SUPPORT DEVELOPMENT ENE INTO THE NRN HIGH PLNS. POTENTIAL

WILL EXIST FOR A FEW SUPERCELLS AND SUSTAINED STORM CLUSTERS WITH

LARGE HAIL...LOCALLY DMGG WIND...AND PERHAPS A TORNADO THROUGH MID

EVE.



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 500. MEAN STORM

MOTION VECTOR 25025.





...CORFIDI

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