

000 

WWUS20 KWNS 122058

SEL9

SPC WW 122058

IAZ000-MOZ000-130400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 589

NWS STORM PREDICTION CENTER NORMAN OK

400 PM CDT SUN AUG 12 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST IOWA

       EXTREME NORTHWEST AND NORTH CENTRAL MISSOURI



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

1100 PM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTH OF

OMAHA NEBRASKA TO 35 MILES NORTH OF KIRKSVILLE MISSOURI.  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 588...



DISCUSSION...BOW ECHO MCS APPEARS TO BE ORGANIZING W OF OMAHA...AND

THIS CONVECTIVE COMPLEX WILL LIKELY PROGRESS ESEWD ALONG A

BAROCLINIC ZONE NEAR THE MO/IA BORDER.  MLCAPE VALUES OF 4000-5000

J/KG AND MODEST DEEP LAYER SHEAR ALONG THE BOUNDARY WILL HELP

MAINTAIN STORM INTENSITY INTO THE EVENING.  RELATIVELY WIDESPREAD

DAMAGING WINDS WILL BE POSSIBLE ALONG THE PATH OF THIS

SYSTEM...ALONG WITH LARGE HAIL.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM

MOTION VECTOR 29035.





...THOMPSON

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