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323 

WWUS20 KWNS 212041

SEL9

SPC WW 212041

IDZ000-UTZ000-WYZ000-220300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 489

NWS STORM PREDICTION CENTER NORMAN OK

240 PM MDT SUN JUN 21 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IDAHO

       NORTHERN INTO CENTRAL UTAH

       FAR SOUTHWEST WYOMING



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 240 PM UNTIL 900

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 65

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

DUGWAY UTAH TO 45 MILES NORTHEAST OF POCATELLO IDAHO.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU9).



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 488...



DISCUSSION...SEVERE THUNDERSTORMS ARE ONGOING THIS AFTERNOON IN TWO

CLUSTERS...ONE OVER E-CENTRAL UT AND ANOTHER FROM ERN ID INTO FAR

NERN NV.  ACTIVITY WILL LIKELY CONTINUE FOR SEVERAL HOURS WITH

THREATS OF LARGE HAIL AND ISOLATED DAMAGING WINDS GIVEN MODEST

INSTABILITY AND EFFECTIVE SHEAR FROM 40-50 KT.  EXPECT STORMS MOVING

ENEWD ALONG WRN BAND WILL PERSIST THE LONGEST THIS EVENING INTO ERN

ID/NRN UT...WITH STRONGER STORMS EVOLVING INTO SUPERCELLS AND

ORGANIZED LINES/CLUSTERS.



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 400. MEAN STORM

MOTION VECTOR 23020.





...EVANS

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