875
ACUS02 KWNS 051728
SWODY2
SPC AC 051727

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CST Wed Feb 05 2025

Valid 061200Z - 071200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY MORNING
ACROSS PARTS OF SOUTHEASTERN KENTUCKY AND ADJACENT PORTIONS OF
TENNESSEE...VIRGINIA...WEST VIRGINIA....

...SUMMARY...
Strong thunderstorms posing at least some risk for scattered
potentially damaging wind gusts and perhaps small hail may impact
parts of southeastern Kentucky and adjacent portions of northern
Tennessee, southwestern Virginia and West Virginia early Thursday.

...Discussion...
Models indicate that large-scale ridging centered over the
northeastern Pacific will be maintained through this period,
although it appears that an embedded mid-level high to the southeast
of the Aleutians is in the process of weakening.  As this proceeds,
the downstream mid-level low, currently offshore of the Pacific
Northwest, is also forecast to weaken, and a more significant
upstream perturbation may begin to migrate inland across
Oregon/northern California coastal areas by late Thursday night.
Downstream, it appears that broad mid-level ridging will build
across the northern Rockies and Great Plains, eastward into the
lower Ohio Valley, to the north of broad ridging centered over the
subtropical western Atlantic through northern Mexico, and in the
wake of a significant mid-level trough accelerating across and east
of the Great Lakes through Canadian Maritimes.

The latter feature may be accompanied by cyclogenesis across the St.
Lawrence Valley, and/or across the Canadian Maritimes by the end of
the period, but models vary concerning this.  However, it does
appear that the leading edge of a slowly modifying surface cold
intrusion to the lee of the Rockies will advance through the Mid
Atlantic and south of the Ohio Valley, while remaining generally
stalled across parts of the southern Great Plains.  At the same
time, a return flow of moisture may continue across the western Gulf
Basin through the northwestern Gulf Coast/lower Mississippi Valley
and middle/southern Atlantic Seaboard.  Beneath relatively warm
layers at mid/upper levels, potential instability is likely to
remain weak, and capped, except in a corridor near the southward
advancing front, from parts of the Ozark Plateau/Mid South into the
Alleghenies and east of the Blue Ridge, where scattered thunderstorm
development is possible Thursday into Thursday night.

...Mid South into Allegheny/Cumberland Plateau...
In response to a short wave perturbation, consolidating with the
larger-scale mid-level troughing progressing into/through the Great
Lakes late tonight into early Thursday, lower/mid-tropospheric wind
fields are forecast to undergo considerable intensification across
and east-northeast of the lower Ohio Valley vicinity.  It appears
that this will include strengthening to 50-70+ kt within a
southwesterly to westerly regime in the 850-500 mb layer, across a
narrow destabilizing pre-frontal corridor across southeastern
Kentucky and adjacent portions of surrounding states by 12Z
Thursday.

However, where large-scale ascent is able to overcome mid-level
inhibition and support thunderstorm development, RAP and NAM
forecast soundings exhibit mid-level lapse rates supportive of only
weak CAPE, which probably will remain rooted above a saturated near-
surface layer characterized by moist adiabatic to more stable lapse
rates.  While this is generally expected to minimize the risk for
severe weather, small hail might not be out of the question in
stronger storms, and it is possible that latent cooling associated
with melting might enhance downdrafts sufficiently to aid the
downward transfer of stronger momentum to the surface.

..Kerr.. 02/05/2025

$$