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445 

WWUS20 KWNS 132027

SEL6

SPC WW 132027

NDZ000-SDZ000-140400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 386

NWS STORM PREDICTION CENTER NORMAN OK

225 PM MDT WED JUN 13 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL NORTH DAKOTA

       NORTHWEST AND NORTH-CENTRAL SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 225 PM UNTIL

1000 PM MDT.



HAIL TO 2.5 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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES EAST OF RAPID

CITY SOUTH DAKOTA TO 15 MILES NORTHEAST OF GARRISON NORTH DAKOTA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON INTO EVENING AHEAD OF SHORTWAVE TROUGH AND

ASSOCIATED COLD FRONT MOVING OUT OF THE NRN HIGH PLAINS.  WARM

SECTOR ENVIRONMENT IS CHARACTERIZED BY STEEP LAPSE RATES AND

BOUNDARY LAYER DEWPOINTS IN THE 50S...YIELDING MLCAPE OF 1000-1500

J/KG.  WHEN COUPLED WITH 50 KT OF DEEP-LAYER SHEAR...SETUP WILL

FAVOR SUPERCELLS AND BOWING STRUCTURES CAPABLE OF LARGE HAIL AND

DAMAGING WIND GUSTS.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 27025.





...MEAD

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