976
ACUS02 KWNS 251725
SWODY2
SPC AC 251723

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1223 PM CDT Tue Jun 25 2024

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE OHIO VALLEY INTO THE MID-ATLANTIC AND NORTHEAST...

...SUMMARY...
Scattered damaging winds are possible over parts of the Ohio Valley
into the Mid-Atlantic and Northeast on Wednesday.

...OH Valley to Mid-Atlantic/Northeast...

An upper trough will progress eastward on Wednesday from the
Mid/Upper MS Valley to the Northeast/Mid-Atlantic. A seasonally
moist airmass will be in place across much of the Midwest to the
Mid-Atlantic where strong heating will support moderate to strong
destabilization. Forcing for ascent associated with the
eastward-advancing upper trough and one or more MCVs moving across
the region will support scattered to numerous strong/severe
thunderstorms through the period.

One cluster of strong/severe thunderstorms is expected to be focused
from PA eastward into the NJ/southern NY vicinity ahead of a
southward sagging cold front. Effective shear magnitudes around
30-40 kt will support a few supercell and/or bowing structures.
Steep low and midlevel lapse rates, with mixing to around 1 km,
suggest damaging gusts and isolated large hail will be the main
hazards with this activity. Another cluster of strong/severe storms
is expected to develop over the higher terrain of eastern KY/WV and
northern VA. Vertical shear will be weaker with southward extent,
but deeper mixing with very steep lapse rates is noted in forecast
soundings. Damaging gusts and isolated hail will also be possible
with this activity. Some potential may exist for higher severe
probabilities in subsequent outlooks for portions of the
Mid-Atlantic/Northeast if an organized bowing structure can develop.
However, confidence in this scenario is too low at this time for
categorical upgrades.

Additional storms are expected along the southward developing cold
front during the late afternoon into evening closer to the OH River
in southern IN and central KY. Weaker shear will limit longevity of
more organized cells, but strong instability and steep lapse rates
will still support localized strong gusts and marginal hail.

...Ozarks/ArkLaTex into MS...

Most forecast guidance, including various CAMs, are in good
agreement that convection will be ongoing Wednesday morning across
the Ozarks. There is more uncertainty regarding the evolution of
this activity through the day. However, it seems likely that
convection will either continue to develop south across parts of
OK/northeast TX/AR/LA and MS. Southwesterly low-level winds will
remain light, but vertically veering profiles with strengthening
north/northwesterly flow above 700 mb will foster around 40 kt
effective shear magnitudes across parts of OK/TX/AR/LA. Shear will
be weaker with southeast extent, but strong storms may persist
southward into central MS as well. A developing cold pool, coupled
with strong instability and PW values approaching 2 inches, will
support maintenance/re-intensification of morning activity as
outflow propagates southward. This activity will mainly pose a risk
for strong/damaging gusts, and the Marginal (level 1 of 5) risk has
been extended southwestward with the Day 2 update. If current trends
persist, portions of this area may need an upgrade to Slight (level
2 of 5) risk in subsequent outlooks.

...Central High Plains...

An upper ridge is forecast to be centered along the Rockies on
Wednesday. However, forecast guidance depicts a weak shortwave
impulse/vorticity maxima rotating through the ridge in the vicinity
of the central Rockies and emerging into the High Plains during the
afternoon/evening. Deep-layer flow will be somewhat weak, but
vertically veering profiles suggest around 25-30 kt effective shear
magnitudes will be possible. Steep midlevel lapse rates will support
a corridor of 1000-2000 J/kg MLCAPE. This should aid in transient
organized cells amid modest boundary-layer moisture. Isolated
strong/severe gusts and large hail will be possible.

..Leitman.. 06/25/2024

$$