..SUMMARY
SEVERE THUNDERSTORMS, ASSOCIATED WITH LARGE HAIL, DAMAGING GUSTS,
AND TORNADOES, SOME OF WHICH MAY BE SIGNIFICANT, WILL BE POSSIBLE
FROM LATE THIS AFTERNOON INTO THE OVERNIGHT, ACROSS PORTIONS OF THE
OHIO VALLEY AND SOUTHERN GREAT LAKES.
..OH VALLEY
A FAST-MOVING SOUTHERN-STREAM SHORTWAVE TROUGH OVER THE CENTRAL
PLAINS WILL TRACK EASTWARD TODAY AND BEGIN AFFECTING PARTS OF MO BY
LATE AFTERNOON OR EARLY EVENING. MOST 12Z GUIDANCE SUGGESTS THAT AT
LEAST ISOLATED THUNDERSTORM DEVELOPMENT WILL BEGIN AROUND/AFTER DUSK
AS THE LARGE-SCALE FORCING OVERSPREADS THE NORTHERN EXTENT OF
MOIST/UNSTABLE AIR MASS FROM SOUTHWEST MO INTO SOUTHERN IL. THESE
STORMS WILL INTENSIFY AND TRACK EASTWARD OVERNIGHT ROUGHLY ALONG THE
OH RIVER, MOVING INTO PARTS OF OH/WV/PA BY EARLY MORNING WEDNESDAY.
INITIAL STORMS MAY BE DISCRETE, WITH SUFFICIENT VERTICAL SHEAR FOR
SUPERCELLS STRUCTURES CAPABLE OF ALL SEVERE HAZARDS. AS THE NIGHT
PROGRESSES, ACTIVITY WILL LIKELY EVOLVE INTO FAST-MOVING BOWING
STRUCTURES WITH AN ENHANCED RISK OF DAMAGING WIND GUSTS AND A FEW
TORNADOES. A STRONG TORNADO OR TWO CANNOT BE RULED OUT. HAVE ADDED
AN ENH RISK AREA FOR THIS SCENARIO OVERNIGHT.