

471 

WWUS20 KWNS 042013

SEL9

SPC WW 042013

IDZ000-ORZ000-050300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 329

NWS STORM PREDICTION CENTER NORMAN OK

210 PM MDT THU JUN 4 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWESTERN IDAHO

       EASTERN OREGON



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 210 PM UNTIL

900 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 95

STATUTE MILES EITHER SIDE OF A LINE FROM 45 MILES NORTH OF

REDMOND OREGON TO 60 MILES EAST SOUTHEAST OF BOISE 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 327...WW 328...



DISCUSSION...STORMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSIFY THROUGH THE AFTERNOON AS AIR MASS CONTINUES TO WARM AND

DESTABILIZE. MODERATE INSTABILITY AND DEEP LAYER SHEAR AT 40-50 KT

WILL BE SUPPORTIVE OF SUPERCELLS. SEVERE HAIL IS EXPECTED TO BE THE

PRIMARY THREAT...THOUGH STEEP LOW LEVEL LAPSE RATES WILL ALSO

SUPPORT DAMAGING WINDS.



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 450. MEAN STORM

MOTION VECTOR 15030.





...IMY

