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000 

WWUS20 KWNS 192053

SEL0

SPC WW 192053

MTZ000-SDZ000-WYZ000-200400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 580

NWS STORM PREDICTION CENTER NORMAN OK

255 PM MDT THU JUN 19 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF SOUTHEAST MONTANA

       PARTS OF WESTERN SOUTH DAKOTA

       MUCH OF NORTHEAST WYOMING



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 255 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 95

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

NORTHEAST OF BROADUS MONTANA TO 20 MILES SOUTH SOUTHWEST OF

DOUGLAS WYOMING.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 577...WW 578...WW 579...



DISCUSSION...SCATTERED THUNDERSTORMS DEVELOPING ACROSS THE WATCH

AREA WHERE AIR MASS IS CHARACTERIZED BY VERY STEEP LAPSE RATES AND

MDT DEEP LAYER SHEAR.  MLCAPES UPWARD TO 1500 J/KG WILL SUPPORT NOT

ONLY PULSE SEVERE BUT ISOLATED SUPERCELLS WITH ENHANCED THREAT OF

LARGE HAIL AND DAMAGING WINDS AS THE ACTIVITY MOVES E THRU THIS

EVENING.



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 27020.





...HALES

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