Their graphic update for Monday is pretty much on the same thinking as my previous discussion except that the big low is already on the move. This morning we had some showers and t’storms in the east and southeastern part of the viewing area. So the morning risk panned out to an extent. If you notice, they have the convective t’storm area a shade west and south of Louisville and points to the east and south. This shift is a reflection of the earlier than anticipated shift of the big upper low. Our lapse rates Monday afternoon are good but the air aloft is pretty dry so rain/storm chances appear marginal.
Here is what the SPC says about the Ohio Valley:
…OH VALLEY/APPALACHIANS TO THE EAST COAST…
PERSISTENT UPPER TROUGH OVER THE GREAT LAKES AND OH/TN VALLEY
REGIONS THIS MORNING IS ALREADY BEGINNING TO ACCELERATE/MOVE
EWD…AND MODELS BRING TROUGH ACROSS THE LOWER LAKES/APPALACHIANS
THIS EVENING. AS HAS BEEN THE CASE THE PAST FEW DAYS…A LARGE AREA
OF SEVERE THUNDERSTORM POTENTIAL WILL DEVELOP AHEAD OF THIS FEATURE
FROM THE CAROLINAS NWD INTO THE UPPER OH RIVER VALLEY/NEW ENGLAND
TODAY. ACTIVITY WILL ONCE AGAIN DEVELOP IN SEVERAL EPISODES AS
HEATING AND DEEP ASCENT/COOLING ALOFT PROVIDE INCREASING INSTABILITY
THROUGH THE AFTERNOON…DESPITE WIDESPREAD AREA OF MOIST
CONVECTION/CLOUDS ALREADY IN PLACE OVER THE REGION. LOW LEVEL FLOW
WILL REMAIN FAIRLY WEAK…ALTHOUGH MODERATE SWLY WINDS ALOFT WILL
SUSTAIN 25-35 KT DEEP LAYER SHEAR. THIS WILL SUPPORT ORGANIZATION
INTO LINES/CLUSTERS AND POSSIBLY A SUPERCELL OR TWO…PRODUCING
LARGE HAIL AND DAMAGING WINDS.
