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WWUS20 KWNS 062152

SEL3

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NEZ000-SDZ000-WYZ000-070500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 433

NWS STORM PREDICTION CENTER NORMAN OK

355 PM MDT MON JUN 6 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN NEBRASKA PANHANDLE

       SOUTHERN AND WESTERN SOUTH DAKOTA

       EASTERN WYOMING



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 355 PM UNTIL

1100 PM MDT.



HAIL TO 2 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 90 MILES WEST OF

RAPID CITY SOUTH DAKOTA TO 35 MILES EAST OF CHAMBERLAIN SOUTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 LATE THIS AFTERNOON INTO EVENING WITHIN A HOT AND DEEPLY

MIXED BOUNDARY LAYER WHERE MLCAPE VALUES HAVE INCREASED TO 1000-2500

J/KG.  WATCH AREA WILL REMAIN TO THE S AND E OF STRONGER DEEP-LAYER

WIND FIELD AND RESULTANT MORE INTENSE VERTICAL SHEAR.

NONETHELESS...THE PRESENCE OF VERY STEEP LAPSE RATES AND 40+ DEGREE

T/TD SPREADS IS RESULTING IN AN ENVIRONMENT QUITE FAVORABLE FOR

DAMAGING WINDS AND LARGE HAIL.



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 24025.





...MEAD

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