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WWUS20 KWNS 301734

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 251

NWS STORM PREDICTION CENTER NORMAN OK

1235 PM CDT THU MAY 30 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  EAST-CENTRAL AND SOUTHEAST IOWA

  WESTERN AND CENTRAL ILLINOIS

  EASTERN MISSOURI



* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 1235 PM

  UNTIL 800 PM CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL TORNADOES POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH LIKELY

  SEVERAL LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE

MILES EAST AND WEST OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF

FARMINGTON MISSOURI TO 30 MILES EAST NORTHEAST OF DUBUQUE IOWA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 250...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY ACROSS THE WATCH AREA THIS AFTERNOON AS LARGE-SCALE

FORCING INCREASES AHEAD OF MIDLEVEL TROUGH.  THE AMBIENT AIR MASS IS

QUITE MOIST AND WHEN COUPLED WITH TEMPERATURES IN THE 80S IS

RESULTING IN MLCAPE OF 1000-2000 J/KG.  GIVEN THE COLOCATION OF A

40-50 KT MIDLEVEL JET AND 40-50 KT LLJ...MORE THAN SUFFICIENT

VERTICAL SHEAR EXIST FOR SUPERCELLS AND BOWS CAPABLE OF DAMAGING

WINDS AND A FEW TORNADOES.



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

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

500. MEAN STORM MOTION VECTOR 22030.





...MEAD

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