979
ACUS02 KWNS 141712
SWODY2
SPC AC 141710

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1110 AM CST Fri Nov 14 2025

Valid 151200Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE SATURDAY
AFTERNOON AND EVENING ACROSS PARTS OF EASTERN OHIO...WESTERN
PENNSYLVANIA AND NORTHERN WEST VIRGINIA...

...SUMMARY...
Showers and a few thunderstorms may be accompanied by strong wind
gusts across parts of the upper Ohio Valley late Saturday afternoon
through Saturday evening.

...Discussion...
Although smaller-scale developments remain uncertain, latest model
output offers little change to prior runs concerning the large-scale
pattern evolution Saturday through Saturday night.  It still appears
that a more progressive flow emanating from the northern
mid-latitude Pacific, including a prominent cyclone on its leading
edge, will begin to impinge on a blocked regime which has evolved
across parts of eastern North America into the Atlantic.  The
cyclone is likely to undergo considerable deformation and weaken,
but an emerging mid-level perturbation is forecast to dig across the
upper through lower Great Lakes region, accompanied by secondary
surface cyclogenesis.

Upstream, the westerlies may undergo notable amplification,
including building ridging across and east of the Canadian and
northern U.S. Rockies, as well as across parts of the central into
eastern northern mid-latitude Pacific.  In between the ridge axes,
models indicate that splitting troughing will progress across the
eastern mid-latitude Pacific.  With the approach of the digging
southern portion of this trough, an initially cut-off low offshore
of the southern California/northern Baja coast is forecast to
accelerate into the Southwest late Saturday through Saturday night.

...Upper Ohio Valley...
Within the warm sector of the developing surface low, modest
low-level moisture return is forecast.  Both NAM and Rapid Refresh
forecast soundings indicate that this will contribute to the
development of thermodynamic profiles characterized by at least weak
conditional and convective instability in the lowest 5-6 km AGL,
becoming focused ahead of a southward advancing cold front, across
parts of the mid into upper Ohio Valley/Allegheny Plateau vicinity
by late Saturday afternoon.

Where the weak boundary-layer destabilization occurs, it appears
that a warm layer aloft may tend to suppress thunderstorm
development, and mid/upper forcing for ascent to overcome the
inhibition remains unclear due to model spread.  However, there does
appear a general consensus for a pocket of modest mid-level cooling
across eastern Ohio into the western slopes of the Allegheny
Mountains late Saturday afternoon into Saturday evening.  This may
be accompanied by the development of a relatively compact band of
stronger showers and thunderstorms, in the presence of strengthening
lower/mid-tropospheric wind fields (including 40-50 kt mean
west-northwesterly flow).  Perhaps aided by latent cooling in
downdrafts associated with melting small hail, this activity may
contribute to the downward transfer of stronger winds to the
surface, before weakening will crossing the Allegheny Mountains
Saturday evening.

...Southwest...
It still appears that a pocket of colder mid-level air,
characterized by 500 mb temperatures as cold as near or just below
-20 C, will finally spread inland late Saturday through Saturday
night.  These temperatures are generally on the warmer side compared
to cool season environments typically conducive to low-topped
convective capable of producing lightning across and inland of
Pacific coastal areas.  However, it is possible that low-level
moisture return emanating from the lower latitude eastern Pacific
and Gulf of California may compensate and contribute to
thermodynamic profiles at least minimally sufficient for
thunderstorms.  Even if this occurs, particularly near southern
California coastal areas, generally saturated profiles with very
weak CAPE, and low-level hodographs becoming modest to weak, seem
likely to minimize the risk for severe weather.

Otherwise, it might not be out of the question that preceding
elevated moisture return contributes to layers of weak conditional
instability minimally supportive of convection capable of producing
lightning across parts of the Mojave Desert/lower Colorado Valley
vicinity.

..Kerr.. 11/14/2025

$$