

000 

WWUS20 KWNS 182210

SEL4

SPC WW 182210

IDZ000-UTZ000-WYZ000-190500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 614

NWS STORM PREDICTION CENTER NORMAN OK

410 PM MDT SAT AUG 18 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IDAHO

       NORTHERN UTAH

       WESTERN WYOMING



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 410 PM UNTIL

1100 PM MDT.



HAIL TO 1.5 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 55

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF CODY

WYOMING TO 40 MILES SOUTH SOUTHEAST OF MALAD CITY IDAHO.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU4).



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...SCTD TSTMS...INCLUDING SOME SUSTAINED STORMS/POSSIBLE

SUPERCELLS...EXPECTED TO PERSIST OVER WW AREA THIS EVENING AS REGION

IS GLANCED BY SPEED MAX ROUNDING SE QUADRANT OF VANCOUVER ISLAND UPR

LOW.  COMBINATION OF 30KT DEEP SWLY SHEAR WITH STRONG SFC HEATING

AND PWS AOA 1 INCH SUGGESTS POTENTIAL FOR SVR HAIL/WIND WITH

STRONGEST ACTIVITY.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 24030.





...CORFIDI

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