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555 

WWUS20 KWNS 072203

SEL6

SPC WW 072203

IDZ000-MTZ000-WYZ000-080500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 396

NWS STORM PREDICTION CENTER NORMAN OK

400 PM MDT SUN JUL 7 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  PARTS OF EASTERN IDAHO

  MUCH OF CENTRAL AND SOUTHERN MONTANA

  NORTHERN WYOMING



* EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

  1100 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 115

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES SOUTH OF

HELENA MONTANA TO 65 MILES EAST SOUTHEAST OF BROADUS MONTANA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 394...WW 395...



DISCUSSION...STORMS CONTINUE TO DEVELOP AND MOVE EWD THIS AFTERNOON

ACROSS THE EASTERN IDAHO/MONTANA/WYOMING VICINITY...AHEAD OF A WEAK

MID-LEVEL SHORT-WAVE TROUGH MOVING ACROSS THE AREA.  WITH AMPLE

INSTABILITY DEVELOPING THROUGH THE PEAK HEATING HOURS AND MODERATE

ENELY MID-LEVEL FLOW YIELDING DEEP-LAYER SHEAR SUFFICIENT FOR AT

LEAST ISOLATED SEVERE STORMS...EXPECT LOCALLY DAMAGING WINDS AND

LARGE HAIL WITH STRONGER CELLS AS CONVECTION SHIFTS EWD TOWARD THE

NRN HIGH PLAINS THROUGH THE EVENING HOURS.



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 26035.





...GOSS

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