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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 234

NWS STORM PREDICTION CENTER NORMAN OK

710 PM CDT THU MAY 3 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHERN IOWA

       EXTREME WEST CENTRAL ILLINOIS

       EXTREME NORTHEAST KANSAS

       NORTHERN MISSOURI



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 710 PM

UNTIL 100 AM CDT.



TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTH NORTHWEST OF

SAINT JOSEPH MISSOURI TO 35 MILES SOUTHEAST OF BURLINGTON IOWA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU4).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 231...WW 232...WW 233...



DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INCREASE IN

COVERAGE/INTENSITY THIS EVENING THROUGH EARLY TONIGHT ACROSS NRN

MO/SRN IA AS LOW-LEVEL WAA INCREASES ALONG A DIFFUSE/REMNANT OUTFLOW

BOUNDARY THAT IS DRIFTING NWD INTO IA.  00Z TOP SOUNDING IS

REPRESENTATIVE OF THE STRONG INSTABILITY PRESENT ACROSS THE SRN/WRN

PORTIONS OF THE WATCH AREA...AND VERTICAL SHEAR IS AT LEAST

MARGINALLY FAVORABLE FOR SUPERCELLS WITH SOME RISK FOR A TORNADO OR

TWO.  OTHERWISE...VERY LARGE HAIL WILL BE POSSIBLE WITH THE MORE

DISCRETE STORMS IN THE NEXT FEW HOURS...WHILE THE RISK FOR DAMAGING

WINDS WILL INCREASE AS STORMS MERGE AND GROW UPSCALE INTO

BANDS/CLUSTERS TONIGHT.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 27025.





...THOMPSON

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