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290 

WWUS20 KWNS 212009

SEL7

SPC WW 212009

MTZ000-NEZ000-SDZ000-WYZ000-220300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 367

NWS STORM PREDICTION CENTER NORMAN OK

310 PM CDT MON JUN 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHEASTERN MONTANA

       PARTS OF NEBRASKA PANHANDLE

       PARTS OF WESTERN SOUTH DAKOTA

       A LARGE PART OF EASTERN WYOMING



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 310 PM UNTIL

1000 PM CDT.



TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE

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

MILES CITY MONTANA TO 25 MILES WEST OF SIDNEY NEBRASKA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU7).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 366...



DISCUSSION...AIR MASS HAS BECOME VERY UNSTABLE ACROSS THE WATCH WITH

LITTLE REMAINING CINH.  WITH APPROACH OF THE UPPER TROUGH AND

ASSOCIATED STRONGER SHEAR...CONDITIONS SUPPORT DEVELOPMENT OF

SUPERCELLS.  SEVERE THUNDERSTORMS WILL FORM VICINITY HIGHER TERRAIN

AND DEVELOP/MOVE EWD. SUPERCELLS WILL BE ASSOCIATED WITH VERY LARGE

HAIL AND POSSIBLE TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 24030.





...HALES

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