

495 

WWUS20 KWNS 250627

SEL2

SPC WW 250627

ILZ000-INZ000-251200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 622

NWS STORM PREDICTION CENTER NORMAN OK

125 AM CDT SAT JUL 25 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN ILLINOIS

       WESTERN AND SOUTHWEST INDIANA



EFFECTIVE THIS SATURDAY MORNING FROM 125 AM UNTIL 700 AM CDT.



HAIL TO 1 INCH 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES NORTHEAST OF

BLOOMINGTON INDIANA TO 40 MILES WEST OF SALEM ILLINOIS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU2).



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 620...WW 621...



DISCUSSION...SWRN END OF EXISTING IL/IND MCS EXPECTED TO BE LOCATION

OF STRONGEST NEW STORM DEVELOPMENT FOR THE NEXT SEVERAL

HOURS...GIVEN /1/ CONFIGURATION OF SFC-BASED INSTABILITY FIELD AND

/2/ PRESENCE OF DEEP LOW TO MID LVL NNWLY FLOW SHOWN ON ILX VWP.

GLANCING INFLUENCE OF UPR GRT LKS TROUGH AND ASSOCIATED WIND FIELD

SUGGEST A CONTINUED THREAT FOR LOCALLY DMGG WIND AND POSSIBLY

MARGINALLY SVR HAIL.



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

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

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

VECTOR 31030.





...CORFIDI

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