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WWUS20 KWNS 041820

SEL7

SPC WW 041820

KYZ000-OHZ000-PAZ000-WVZ000-050100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 567

NWS STORM PREDICTION CENTER NORMAN OK

220 PM EDT WED AUG 4 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHEAST KENTUCKY

       SOUTHEAST OHIO

       EXTREME SOUTHWEST PENNSYLVANIA

       CENTRAL AND NORTHERN WEST VIRGINIA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 220 PM UNTIL

900 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 65

STATUTE MILES EITHER SIDE OF A LINE FROM 25 MILES WEST OF

ZANESVILLE OHIO TO 30 MILES SOUTH SOUTHWEST OF ELKINS WEST

VIRGINIA.  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 566...



DISCUSSION...THE CLUSTER OF STORMS IN CENTRAL OH...WITH A HISTORY OF

WIND GUSTS NEAR 65 MPH...WILL LIKELY CONTINUE TO MOVE SEWD FROM OH

INTO WV ALONG A WEAK INSTABILITY GRADIENT.  MLCAPE HAS INCREASED TO

NEAR 4000 J/KG WITH MINIMAL CONVECTIVE INHIBITION IN THE WARM SECTOR

IN ADVANCE OF THE STORMS...COINCIDENT WITH A BELT OF 30-40 KT NWLY

MIDLEVEL FLOW.  THE COMBINATION OF THESE FACTORS WILL HELP MAINTAIN

THE STORM CLUSTER AND SUPPORT NEW STORM DEVELOPMENT...WITH A

CONTINUED THREAT FOR DAMAGING WINDS AND SOME HAIL THROUGH THE

AFTERNOON/EVENING.



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 550. MEAN STORM

MOTION VECTOR 31030.





...THOMPSON

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