

919 

WWUS20 KWNS 191218

SEL7

SPC WW 191218

IAZ000-ILZ000-WIZ000-LMZ000-192000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 477

NWS STORM PREDICTION CENTER NORMAN OK

715 AM CDT FRI JUN 19 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IOWA

       NORTHERN ILLINOIS

       SOUTHERN WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS FRIDAY MORNING AND AFTERNOON FROM 715 AM UNTIL 300

PM CDT.



HAIL TO 2 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTHWEST

OF CEDAR RAPIDS IOWA TO 20 MILES SOUTH OF MEIGS FIELD ILLINOIS.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 475...WW 476...



DISCUSSION...E CNTRL IA STORM CLUSTER EXPECTED TO CONTINUE GENERALLY

ENE INTO WRN IL...WITH A CONTINUED THREAT FOR HIGH WIND/HAIL.  OTHER

STORMS MAY FORM IN ITS VICINITY IN RESPONSE TO SFC HEATING A BIT

LATER THIS MORNING...AND ATOP OUTFLOW LEFT BY OVERNIGHT MCS IN NRN

IL.  AREA WIND PROFILES AND THERMODYNAMIC ENVIRONMENT APPEAR

FAVORABLE FOR BOWING SEGMENTS WITH HIGH WIND/HAIL.  EXACT NATURE OF

STORM INTERACTION WITH/DEVELOPMENT ALONG THE NRN IL OUTFLOW BOUNDARY

IS UNCERTAIN ATTM.  BUT A NON-ZERO THREAT COULD DEVELOP FOR LOW

LEVEL STORM ROTATION/POSSIBLE TORNADOES AS BOUNDARY LAYER RECOVERY

OCCURS IN WAKE OF GUST FRONT.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 26040.





...CORFIDI

