

795 

WWUS20 KWNS 302332

SEL7

SPC WW 302332

INZ000-OHZ000-310600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 317

NWS STORM PREDICTION CENTER NORMAN OK

730 PM EDT SAT MAY 30 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL INDIANA

       SOUTHWEST OHIO



EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 730 PM

UNTIL 200 AM EDT.



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 45

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

LAFAYETTE INDIANA TO 70 MILES EAST SOUTHEAST OF DAYTON OHIO.  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 316...



DISCUSSION...THUNDERSTORMS INCREASING COINCIDENT WITH WEAK FRONTAL

WAVE DEVELOPMENT ACROSS IL/IND BORDER ATTM. THIS ACTIVITY APPEARS TO

BE FOCUSED ALONG AND NORTH OF RESIDUAL FRONTAL ZONE EXTENDING NWWD

FROM THE OH RIVER TO THE FRONTAL WAVE/LOW. UNSTABLE WARM SECTOR

SHOULD CONTINUE TO FUEL VIGOROUS STORM UPDRAFTS WITHIN STRONGLY

SHEARED REGIME. PRIMARILY UNIDIRECTIONAL FLOW HAS ALREADY LED TO

NUMEROUS STORM SPLITS WITH BOTH RIGHT AND LEFT MOVERS FAVORED FOR

PERSISTENCE AND LARGE HAIL PRODUCTION. LARGER/UPSCALE ORGANIZATION

INTO SMALL MCS POSSIBLE GIVEN INFLUENCE OF DEVELOPING FRONTAL WAVE

CIRCULATION. STRONG NW FLOW COULD SUPPORT AN INCREASE IN MORE

WIDESPREAD DAMAGING WINDS IF STORM MERGERS LEAD TO MCS DEVELOPMENT

INTO THE EVENING.



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 450. MEAN STORM

MOTION VECTOR 32030.





...CARBIN

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