

770 

WWUS20 KWNS 260157

SEL3

SPC WW 260157

IAZ000-ILZ000-260800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 523

NWS STORM PREDICTION CENTER NORMAN OK

900 PM CDT WED JUL 25 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IOWA

       NORTHWEST ILLINOIS



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 900 PM

UNTIL 300 AM 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 45

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES WEST OF

CEDAR RAPIDS IOWA TO 70 MILES EAST NORTHEAST OF MOLINE ILLINOIS.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 518...WW 519...WW

520...WW 522...



DISCUSSION...LINEAR BANDS OF TSTMS WILL LIKELY TO SPREAD EASTWARD

ACROSS EASTERN IA INTO PORTIONS OF NORTHERN IL. WHILE THE BOUNDARY

LAYER WILL TEND TO COOL THIS EVENING...SUSTENANCE/ORGANIZATION OF

TSTMS WILL BE AIDED BY A STRENGTHENING SOUTHWESTERLY LOW LEVEL JET

AND AN EASTWARD-SPREADING/POTENTIALLY EXPANDING COLD POOL/POTENTIAL

MCV CURRENTLY ACROSS IA. DAMAGING WINDS/SEVERE HAIL WILL BE POSSIBLE

THROUGH MID/LATE EVENING...AND PERHAPS INTO THE OVERNIGHT.



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 500. MEAN STORM

MOTION VECTOR 27030.





...GUYER

