

000 

WWUS20 KWNS 182303

SEL9

SPC WW 182303

IDZ000-ORZ000-WAZ000-190600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 839

NWS STORM PREDICTION CENTER NORMAN OK

405 PM PDT MON AUG 18 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF THE IDAHO PANHANDLE

       LARGE PART OF NORTHEAST OREGON

       MUCH OF EASTERN WASHINGTON



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 405 PM UNTIL

1100 PM PDT.



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 85

STATUTE MILES EAST AND WEST OF A LINE FROM 70 MILES NORTHEAST OF

OMAK WASHINGTON TO 65 MILES SOUTHWEST OF BAKER OREGON.  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 837...WW 838...



DISCUSSION...WITH APPROACH OF THE S/WV TROUGH NOW INTO SWRN

OR...THUNDERSTORMS ARE INCREASING IN NUMBER AND INTENSITY  E OF OR

CASCADES.  WITH STEEP LAPSE RATES AND MLCAPES TO 1000

J/KG...POTENTIAL FOR A FEW SEVERE STORMS INCLUDING DAMAGING WINDS

AND LARGE HAIL WILL SPREAD N/NEWD ACROSS WATCH AREA THRU THE

EVENING.



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 500. MEAN STORM

MOTION VECTOR 19030.





...HALES

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