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WWUS20 KWNS 232109

SEL3

SPC WW 232109

IAZ000-NEZ000-SDZ000-240400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 293

NWS STORM PREDICTION CENTER NORMAN OK

405 PM CDT WED MAY 23 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN IOWA

       EASTERN NEBRASKA

       EXTREME SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 405 PM UNTIL

1100 PM 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 60

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

SPENCER IOWA TO 35 MILES WEST SOUTHWEST OF BEATRICE NEBRASKA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 292...



DISCUSSION...STORMS ARE EXPECTED TO DEVELOP NEAR A SLOW MOVING COLD

FRONT EXTENDING FROM EXTREME SERN SD SSWWD INTO SOUTH CENTRAL NEB

WITHIN THE NEXT 1-2 HRS.  STRONG HEATING HAS OCCURRED AHEAD OF THE

FRONT...AND WHEN COMBINED WITH LARGE SCALE ASCENT APPROACHING FROM

THE WEST...HAVE WEAKENED THE CAP ASSOCIATED WITH A PRE-EXISTING EML.

STRONG WINDS ALOFT ARE PROVIDING SUFFICIENT DEEP LAYER SHEAR TO

SUPPORT SEVERE STORMS INCLUDING POSSIBLE SUPERCELLS.  ACTIVITY IS

EXPECTED TO DEVELOP INTO CONVECTIVE LINE BY THIS EVENING WITH

CONTINUING THREAT FOR LARGE HAIL AND DAMAGING WINDS AS IT SAGS

EWD/SEWD.



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 22035.





...WEISS

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