

426 

WWUS20 KWNS 242202

SEL9

SPC WW 242202

IAZ000-ILZ000-WIZ000-250400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 619

NWS STORM PREDICTION CENTER NORMAN OK

505 PM CDT FRI JUL 24 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEAST AND EAST CENTRAL IOWA

       NORTHWEST ILLINOIS

       SOUTHWEST WISCONSIN



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 505 PM UNTIL

1100 PM CDT.



TORNADOES...HAIL TO 2.5 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 60 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 15 MILES SOUTH OF WATERLOO

IOWA TO 60 MILES SOUTH OF MADISON WISCONSIN.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU9).



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...THIS TORNADO WATCH REPLACES SEVERE

THUNDERSTORM WATCH NUMBER 616...TORNADO WATCH NUMBER 617. WATCH

NUMBER 616 617 WILL NOT BE IN EFFECT AFTER 505 PM CDT.

CONTINUE...WW 618...



DISCUSSION...SUPERCELLS WILL CONTINUE TO DEVELOP IN THE ZONE OF

ASCENT FOCUSED WHERE THE SURFACE COLD FRONT INTERSECTS A NNW-SSE

ORIENTED OUTFLOW BOUNDARY FROM EARLIER CONVECTION ACROSS ERN IA.

LOW-LEVEL SHEAR AND MOISTURE ARE MAXIMIZED ALONG THIS

BOUNDARY...WHERE DEEP LAYER SHEAR AND INSTABILITY BOTH FAVOR

SUPERCELLS.  A FEW TORNADOES...ISOLATED VERY LARGE HAIL...AND

DAMAGING WINDS WILL CONTINUE TO BE THREATS THROUGH EARLY TONIGHT AND

THE FRONT AND AN ASSOCIATED MID LEVEL TROUGH MOVE SEWD FROM MN/WI

TOWARD IA/NRN IL.



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

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

500. MEAN STORM MOTION VECTOR 32020.





...THOMPSON

