

150 

WWUS20 KWNS 191750

SEL3

SPC WW 191750

IAZ000-ILZ000-MOZ000-200000-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 713

NWS STORM PREDICTION CENTER NORMAN OK

1250 PM CDT WED AUG 19 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHEAST IOWA

       WEST CENTRAL AND NORTHWEST ILLINOIS

       EXTREME NORTHEAST MISSOURI



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL

700 PM CDT.



TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS

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



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 35 MILES WEST SOUTHWEST OF

BURLINGTON IOWA TO 30 MILES NORTHEAST OF BLOOMINGTON ILLINOIS.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU3).



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.



DISCUSSION...THUNDERSTORMS HAVE BEEN GRADUALLY INTENSIFYING EARLY

THIS AFTERNOON WITH AN MCV THAT IS MOVING NEWD FROM NE MO TOWARD SE

IA/WRN IL.  A BELT OF ENHANCED LOW-MID LEVEL SHEAR IMMEDIATELY E-NE

OF THE MCV...ALONG WITH BOUNDARY LAYER DEWPOINTS IN THE LOW 70S

ALONG THE NWD MOVING WARM FRONT...WILL SUPPORT A THREAT FOR EMBEDDED

SUPERCELLS WITH A FEW TORNADOES THIS AFTERNOON.



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

SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND

GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.

MEAN STORM MOTION VECTOR 23030.





...THOMPSON

