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WWUS20 KWNS 152226

SEL2

SPC WW 152226

MTZ000-NDZ000-SDZ000-160600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 782

NWS STORM PREDICTION CENTER NORMAN OK

425 PM MDT MON AUG 15 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN MONTANA

       WESTERN AND CENTRAL NORTH DAKOTA

       FAR NORTHWEST AND NORTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS MONDAY AFTERNOON FROM 425 PM UNTIL MIDNIGHT MDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST

SOUTHWEST OF MILES CITY MONTANA TO 45 MILES NORTH NORTHEAST OF

BISMARCK NORTH DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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...TSTMS WILL CONTINUE TO FORM ALONG/N OF AN OUTFLOW

BOUNDARY THAT EXISTS FROM CNTRL THROUGH SWRN ND THIS EVENING.

ADDITIONAL HIGH-BASED STORMS...TIED TO AN UPR-LVL WAVE MOVING

THROUGH THE CNTRL/NRN ROCKIES...WILL ALSO BECOME STRONGER AS THEY

INTERACT WITH WRN FRINGE OF LLVL THETA-E AXIS ALONG THE ND/SD/MT

BORDER EARLY THIS EVE.  MLCAPES IN EXCESS OF 2500 J/KG AND VERTICAL

SHEAR OF 45 KTS WILL BE FAVORABLE FOR SUPERCELLS...PARTICULARLY OVER

ND/SD WITH LARGE HAIL.  ACTIVITY DEVELOPING FARTHER W MAY EVOLVE

INTO BOWING LINE SEGMENTS WITH STRONGER CELLS EVENTUALLY TRACKING

ALONG THE AFOREMENTIONED OUTFLOW BOUNDARY WITH CORRIDORS OF SVR

WINDS.  TO THE N...GUSTY WINDS AND LARGE HAIL WILL BE THE PRIMARY

THREATS ACROSS ECNTRL MT INTO WCNTRL-NRN ND.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

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

MOTION VECTOR 24035.





...RACY

