ACUS02 KWNS 050539
SWODY2
SPC AC 050538

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Sat Oct 05 2024

Valid 061200Z - 071200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible Sunday
afternoon and evening across parts of the western New York and
Pennsylvania into West Virginia.

...Upper Ohio Valley/Lower Great Lakes vicinity...
A mid-latitude cyclone is forecast to begin the period over central
Ontario, with enhanced mid-level flow extending throughout the base
of this system from the Upper Midwest into the Upper Great Lakes and
OH Valley. A pair of shortwave troughs are expected to progress
quickly eastward/northeastward within this belt of stronger flow,
helping to pull the cyclone eastward while also inducing a negative
tilt to the system. By early Sunday, upper troughing will likely
extend from the Ontario/Quebec border southeastward into the
northern Mid-Atlantic.

Primary surface low associated with this system will remain occluded
over Ontario throughout the period. However, a secondary
triple-point low will likely be over central Ontario early Sunday,
with its associated cold front extending southwestward through the
Mid MS Valley. This low is forecast to push eastward across eastern
Ontario during the day, with the cold front progressing
eastward/southeastward as well. A narrow corridor of low 60s
dewpoints is anticipated just ahead of the cold front, which is
expected to combine with cooling mid-level temperatures and foster
modest buoyancy. Initial thunderstorm development along the front is
anticipated across eastern OH, where a favorable combination of
daytime heating and low-level moisture will destabilize the
pre-frontal airmass.

Moderate to strong mid-level flow will extend across the region as
well, which should allow updrafts to stay ahead of the quick-moving
cold front for at least a few hours. Cold mid-level temperatures and
moderate deep-layer vertical shear will support a hail risk with the
strongest updrafts, particularly with initial development. Bowing
line segments will contribute to a threat for damaging gusts as
well. Surface winds will likely veer ahead of the front, limiting
the low-level curvature. Even so, forecast soundings show
southwesterlies strengthening from 15 kt at the surface to 40 kt at
700 mb, which does result in enough storm-relative helicity for some
tornado potential if a discrete mode can be maintained.

...Gulf Coast into the Coastal GA and FL Peninsula...
Easterly/northeasterly low-level flow will persist for another day
across the northern Gulf of Mexico, as a broad area of low pressure
remains in place. Showers and thunderstorms are possible within the
moist airmass, but weak shear should keep storm severity low.

..Mosier.. 10/05/2024

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