SPC AC 250445
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1145 PM CDT Mon Sep 24 2018
Valid 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL APPALACHIANS AND NORTHEAST...
Scattered thunderstorms associated with a wind damage threat are
expected to develop on Wednesday from the central Appalachian
mountains to the Northeast. A tornado threat will also be possible
mainly from eastern Pennsylvania northeastward into New England.
An upper-level trough will move quickly eastward across the Great
Lakes region on Wednesday. At the begining of the period, a cold
front should be located from southwestern Ontario extending
southwestward into the Ohio Valley. This front will advance
east-southeastward across the Northeast and central Appalachian on
Wednesday. A line of thunderstorms should be ongoing along the front
at the start of the period and this line is forecast to gradually
intensify during the day. Scattered thunderstorms will also be
possible ahead of the cold front from the northern Appalachians
southwestward across parts of the Mid Atlantic.
Ahead of the front, surface dewpoints are forecast to be in the mid
to upper 60s F. This should result in weak instability across the
central and northern Appalachians but a corridor of moderate
instability will be possible in the lower elevations of the
Mid-Atlantic. The moist airmass combined with strong winds just
above the surface will be favorable for a wind damage threat with
the faster moving line segments. The potential for wind damage
should be the greatest in eastern Pennsylvania, eastern New York and
western New England where the combination of instability and low to
mid-level flow is forecast to be maximized. A tornado threat may
also accompany the more intense parts of the line, especially across
western New England where the mid-level and low-level jets are
forecast to be closer together.
Although strong deep-layer shear is forecast across parts of the
central Appalachians, low-level flow should be much weaker with
southwestward extent into parts of southern West Virginia and
central to eastern Kentucky. For this reason, the wind damage threat
is expected to be marginal across the southern portion of the
central Appalachian Mountains.
...MAXIMUM RISK BY HAZARD...
Tornado: 5% - Slight
Wind: 15% - Slight
Hail: 5% - Marginal
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z