

102 

WWUS20 KWNS 261434

SEL9

SPC WW 261434

IAZ000-MOZ000-NEZ000-262100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 189

NWS STORM PREDICTION CENTER NORMAN OK

935 AM CDT SUN APR 26 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN IOWA

       SMALL PART OF NORTHWEST MISSOURI

       MUCH OF EASTERN NEBRASKA



EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 935 AM UNTIL 400

PM CDT.



HAIL TO 2.5 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 65

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES SOUTHWEST OF

BEATRICE NEBRASKA TO 30 MILES NORTHEAST OF SPENCER IOWA.  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 188...



DISCUSSION...STRONG WARM ADVECTION OCCURRING ACROSS THE WATCH AREA

WITH 50-60KT LLJ.  WITH A VERY MOIST/UNSTABLE AIR MASS STREAMING NWD

ACROSS SHALLOW COLD LAYER...ELEVATED SEVERE

THUNDERSTORMS...INCLUDING SUPERCELLS ARE LIKELY.  PRIMARY THREAT

WILL BE LARGE HAIL WITH POTENTIAL FOR WIND INCREASING DURING

AFTERNOON AS BOUNDARY LAYER DESTABILIZES SRN PORTION OF WATCH.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 22035.





...HALES

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