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WWUS20 KWNS 040556

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IAZ000-ILZ000-KSZ000-MOZ000-041000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 236

NWS STORM PREDICTION CENTER NORMAN OK

1255 AM CDT FRI MAY 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHEASTERN IOWA

       A SMALL PART OF WESTERN ILLINOIS

       FAR NORTHEAST KANSAS

       NORTHERN MISSOURI



EFFECTIVE THIS FRIDAY MORNING FROM 1255 AM UNTIL 500 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 125

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES EAST

NORTHEAST OF LAMONI IOWA TO 30 MILES SOUTHEAST OF CHILLICOTHE

MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 234. WATCH NUMBER 234 WILL NOT BE IN EFFECT

AFTER 1255 AM CDT. CONTINUE...WW 235...



DISCUSSION...TSTMS EXPECTED TO PERSIST ALONG SRN FRINGE OF DIFFUSE

W-E FRONTAL ZONE OVER SRN IA/NRN MO...SUPPORTED BY 25-30 KT LLJ THAT

WILL FURTHER VEER FROM SWLY TO WSWLY.  OTHER THAN LOW LVL

WAA...FORCING FOR ASCENT WILL REMAIN WEAK.  BUT DEGREE OF BUOYANCY

/PER 00Z TOP RAOB/ AND RELATIVELY RICH MOISTURE INFLOW SUGGEST

CONTINUED RISK FOR SVR HAIL AND STRONG...PRECIP-ENHANCED DOWNDRAFTS

AS THE STORMS GRADUALLY EVOLVE INTO A LARGER SCALE...POSSIBLY

FORWARD-PROPAGATING MCS.



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 27025.





...CORFIDI

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