

000 

WWUS20 KWNS 182239

SEL4

SPC WW 182239

IAZ000-ILZ000-WIZ000-190600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 534

NWS STORM PREDICTION CENTER NORMAN OK

535 PM CDT WED JUL 18 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN IOWA

       WESTERN AND NORTHERN ILLINOIS

       SOUTHERN WISCONSIN



EFFECTIVE THIS WEDNESDAY AFTERNOON AND THURSDAY MORNING FROM 535

PM UNTIL 100 AM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTH

NORTHWEST OF DES MOINES IOWA TO 5 MILES EAST NORTHEAST OF

MARSEILLES ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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

SEVERE THUNDERSTORM WATCH NUMBER 530. WATCH NUMBER 530 WILL NOT

BE IN EFFECT AFTER 535 PM CDT. CONTINUE...WW 529...WW 531...WW

532...WW 533...



DISCUSSION...MCS AND ASSOCIATED LARGER SCALE CIRCULATION IN N CNTRL

IA EXPECTED TO CONTINUE MAINLY ESE ALONG EDGE OF STRONG LOW LVL

INSTABILITY AXIS THIS EVENING...WITH A CONTINUED THREAT FOR EMBEDDED

STORMS WITH HIGH WIND/LARGE HAIL.  SYSTEM MAY CONTAIN BOWING

SEGMENTS AND POSSIBLE SHORT-LIVED SUPERCELLS...ESPECIALLY NEAR

CIRCULATION CENTER AND ALONG WARM ADVECTION WING EXTENDING ESE INTO

NRN IL.  THERE ALSO MAY BE A TENDENCY FOR UPSTREAM DEVELOPMENT /I.E.

NEW CELL FORMATION ON WSW FLANK OF SYSTEM/ LATER THIS EVENING AS LLJ

STRENGTHENS AND VEERS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 31035.





...CORFIDI

