

000 

WWUS20 KWNS 242005

SEL6

SPC WW 242005

MTZ000-NEZ000-SDZ000-WYZ000-250300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 746

NWS STORM PREDICTION CENTER NORMAN OK

305 PM CDT THU JUL 24 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF SOUTHEAST MONTANA

       PARTS OF NORTHERN NEBRASKA

       PARTS OF WESTERN AND SOUTHERN SOUTH DAKOTA

       PARTS OF NORTHEAST WYOMING



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 305 PM UNTIL

1000 PM CDT.



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 90

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES WEST

NORTHWEST OF GILLETTE WYOMING TO 65 MILES SOUTH SOUTHEAST OF

CHAMBERLAIN SOUTH 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.



OTHER WATCH INFORMATION...CONTINUE...WW 744...WW 745...



DISCUSSION...AIRMASS HAS DESTABILIZED WITH LITTLE REMAINING CINH

ACROSS THE WATCH AREA.  WITH STEEP LAPSE RATES AND 30-40KT OF DEEP

LAYER SHEAR...SEVERE THUNDERSTORMS EXPECTED TO DEVELOP VICINITY OF

LOW LEVEL BOUNDARIES AND EWD OFF THE HIGHER TERRAIN.  LARGE HAIL AND

DAMAGING DOWNBURSTS WINDS ARE LIKELY WITH POTENTIAL FOR A FEW

SUPERCELLS THAT WILL ENHANCE SEVERE THREAT.



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 550. MEAN STORM

MOTION VECTOR 29020.





...HALES

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