

213 

WWUS20 KWNS 082311

SEL5

SPC WW 082311

IAZ000-ILZ000-WIZ000-090500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 275

NWS STORM PREDICTION CENTER NORMAN OK

615 PM CDT FRI MAY 8 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IOWA

       NORTHWEST ILLINOIS

       SOUTHWEST WISCONSIN



EFFECTIVE THIS FRIDAY NIGHT FROM 615 PM UNTIL MIDNIGHT CDT.



HAIL TO 1.5 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 75

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF

DUBUQUE IOWA TO 40 MILES SOUTH SOUTHWEST OF MOLINE ILLINOIS.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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...CONTINUE...WW 268...WW 270...WW

271...WW 272...WW 273...WW 274...



DISCUSSION...TSTMS EXPECTED TO PERSIST THROUGH THE EVE IN AREA OF

STRONG LOW TO MID LVL ASCENT AHEAD OF STRONG VORT CROSSING NRN IA.

STRENGTH OF WIND FIELD...CONCENTRATED LOW LVL CONVERGENCE...AND COOL

MID LVL TEMPERATURES SUGGEST A CONTINUED THREAT FOR SVR

WIND/HAIL...DESPITE LIMITED MOISTURE INFLOW.



AVIATION...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 400. MEAN STORM

MOTION VECTOR 26045.





...CORFIDI/JEWELL

