

000 

WWUS20 KWNS 250506

SEL8

SPC WW 250506

IAZ000-KSZ000-MOZ000-251200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 228

NWS STORM PREDICTION CENTER NORMAN OK

1205 AM CDT FRI APR 25 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST AND SOUTH CENTRAL IOWA

       EXTREME NORTHEAST KANSAS

       NORTHWEST MISSOURI



EFFECTIVE THIS FRIDAY MORNING FROM 1205 AM UNTIL 700 AM CDT.



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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTHWEST

OF SHENANDOAH IOWA TO 25 MILES EAST NORTHEAST OF LAMONI IOWA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 226...WW 227...



DISCUSSION...SLIGHTLY ELEVATED THUNDERSTORMS WILL CONTINUE TO

DEVELOP AND SPREAD ENEWD FROM NE KS/SE NEB INTO NW MO AND SW IA

DURING THE EARLY MORNING HOURS.  A FEED OF MODERATE INSTABILITY ON

THE NOSE OF A STRONG SSWLY LLJ WILL SUPPORT STRONG UPDRAFTS...WHILE

EFFECTIVE BULK SHEAR WILL BE SUFFICIENT FOR EMBEDDED SUPERCELL

STRUCTURES.  LARGE HAIL SHOULD BE THE PRIMARY SEVERE THREAT...THOUGH

ISOLATED DAMAGING WINDS MAY ALSO OCCUR.



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 26025.





...THOMPSON

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