

000 

WWUS20 KWNS 212039

SEL0

SPC WW 212039

INZ000-KYZ000-OHZ000-PAZ000-LEZ000-220300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 590

NWS STORM PREDICTION CENTER NORMAN OK

440 PM EDT SAT JUN 21 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME SOUTHEAST INDIANA

       EXTREME NORTH CENTRAL KENTUCKY

       EASTERN AND SOUTHERN OHIO

       NORTHWEST PENNSYLVANIA

       LAKE ERIE



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 440 PM UNTIL

1100 PM EDT.



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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH OF

YOUNGSTOWN OHIO TO 45 MILES SOUTH OF COLUMBUS OHIO.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU0).



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 589...



DISCUSSION...STORMS ARE STRENGTHENING AGAIN ALONG THE LEADING EDGE

OF A LINEAR MCS EXTENDING FROM WRN LAKE ERIE SWWD INTO EAST CENTRAL

INDIANA.  CONVECTION IS LOCATED AHEAD OF A WELL-DEFINED SHORT WAVE

TROUGH MOVING EWD ACROSS THE SRN GREAT LAKES TOWARD THE OHIO VALLEY

WHERE LARGE SCALE ASCENT IS FOCUSED.  AIR MASS HAS WARMED IN ADVANCE

OF THE LINE WITH SURFACE TEMPERATURES NEAR 80F...AND MODERATELY

STEEP LAPSE RATES COUPLED WITH SUFFICIENT LOW LEVEL MOISTURE WILL

CONTINUE TO SUPPORT POTENTIAL FOR SEVERE STORMS INTO THE EVENING

HOURS.



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 27025.





...WEISS

