545
ACUS02 KWNS 280529
SWODY2
SPC AC 280527

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Tue Apr 28 2026

Valid 291200Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY
AFTERNOON AND EVENING IN A CORRIDOR ACROSS SOUTHERN TEXAS THROUGH
THE NORTH CENTRAL GULF COAST...AND ACROSS THE ALLEGHENY PLATEAU INTO
 MID ATLANTIC...

...SUMMARY...
Widely scattered strong to severe storms may impact a corridor from
south of the Texas Big Bend through the north central Gulf Coast
vicinity Wednesday afternoon into evening, with additional strong
storms posing at least some risk for severe weather across the
Allegheny Plateau into Mid Atlantic.

...Discussion...
Models still indicate that mid-level ridging will build inland
across the Canadian Rockies/Pacific Northwest through this period,
but it appears that attempts at a developing embedded high near the
Pacific Northwest coast will become suppressed by a short wave
impulse within the westerlies approaching the British Columbia
coast.  Farther south, a mid-level low merging into a belt of
westerlies emanating from the subtropical eastern Pacific may
accelerate toward southern California/northern Baja coastal areas,
but models continue to substantively vary concerning this motion.

A downstream subtropical high, initially centered over southern
Mexico, may undergo at least some further southwestward suppression,
but it still may maintain considerable influence as far north as
southern Texas through Texas Gulf coast Wednesday through Wednesday
night.  At the same time, in higher latitudes, large-scale troughing
encompassing much of north central and northeastern North America is
forecast to continue slowly digging toward the northern/mid Atlantic
Seaboard. A broad embedded cyclonic mid-level circulation may begin
to form near/north of the Great Lakes region.

The confluent mid-level regime across and east of the Rockies will
likely support southeastward development of cool surface ridging
across much of the Great Plains and Mississippi Valley, in the wake
of a southeastward advancing cold front.  Models generally suggest
that a modest surface low evolving along this front may migrate
from the lower Ohio Valley northeastward through the lower Great
Lakes region, with a modest secondary surface low forming along a
developing warm front to the east of the Blue Ridge by late
Wednesday afternoon into evening, but there is notable spread within
the guidance concerning this evolution.

...Lower Rio Grande Valley into north central Gulf Coast...
Uncertainties abound concerning the convective potential for this
period.  The continuing presence of mid-level ridging and warm
elevated mixed-layer air may be inhibitive to more than isolated
sustained thunderstorm development east of the Rio Grande River, to
the south of Del Rio, through much of Deep South Texas.  Across the
upper Texas coastal plain through much of the Gulf Coast states,
conglomerate convective outflow from thunderstorm activity today
through tonight may slow destabilization ahead of the southward
advancing cold front, and there is spread concerning where this
outflow may end up by 12Z Wednesday.

Still, subtle short wave perturbations within moderate to strong
west-northwesterly mid/upper flow, near/north of the periphery of
the subtropical ridging, may provide support for thunderstorm
initiation with boundary-layer destabilization.  Guidance suggests
that this may include at least pockets of moderate CAPE, sufficient
for isolated to widely scattered intense convection which could
evolve into supercells and/or small organized clusters with
potential to produce severe hail and wind.

...Allegheny Plateau into Mid Atlantic...
Given the spread among the latest model output concerning the
initial surface frontal low migrating through the Ohio Valley, and
the developing surface troughing/warm front to the east of the Blue
Ridge, substantial uncertainty remains concerning the convective
potential for this period.  Remnant convective cloud cover and rain
overspreading the region early in the day may also impede
destabilization.  However, with at least weak to moderate
boundary-layer destabilization, strengthening wind fields and
forcing for ascent associated with an approaching mid-level jet
could become conducive to organized severe storm development.  This
may initiate west of the Allegheny Mountains, and include potential
for evolving supercell structures, before developing to the east of
the Blue Ridge by late Wednesday afternoon into evening.

..Kerr.. 04/28/2026

$$