570
ACUS02 KWNS 231730
SWODY2
SPC AC 231728

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 PM CDT Sun Aug 23 2026

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE CENTRAL HIGH PLAINS AND THE LOWER MISSISSIPPI VALLEY...

...SUMMARY...
Thunderstorms producing scattered severe gusts appear likely across
the central High Plains and Lower Mississippi Valley tomorrow
(Monday). Isolated severe thunderstorms, posing mainly a
damaging/severe gust or sparse hail threat, may also occur across
parts of the Northern Great Basin into the southern High Plains, the
Gulf to Carolina Coastline, and Maine.

...Synopsis...
Upper ridging will persist across the western and central U.S. as an
upper trough is poised to traverse the Northeast and impinge on the
Atlantic tomorrow (Monday). A pronounced mid-level shortwave trough
will crest the ridge and eject into the northern Plains by tomorrow
afternoon, encouraging surface lee troughing along the central High
Plains to the U.S./Canada border. Adequate low-level moisture
advection northward across the Plains, beneath seasonably cooler
temperatures aloft, in conjunction with stronger mid-level flow (and
thus vertical wind shear), will encourage strong to severe
thunderstorm potential over the northern Plains. Meanwhile, some
severe threat may exist with storms across the northern Great Basin,
Maine, and parts of the Gulf coastline.

...Northern Plains to the central High Plains...
Isolated to widely scattered thunderstorms are expected develop
ahead of a surface lee trough from the Canadian border to the
southern High Plains tomorrow afternoon. Mid to upper flow will be
strongest across the northern High Plains into the northern Plains,
where 30-40 kts of westerly 500 mb flow will support similar values
of effective bulk shear. The latest high-resolution guidance
consensus depicts a higher density cluster of multicells and perhaps
supercells developing somewhere around the Black Hills of SD and
propagating south-southeastward into NE. Given merging cold pools,
scattered severe gusts are possible, along with a couple instances
of severe hail. Closer to the Canadian border, convective coverage
is less certain, though 2000-3000 J/kg MLCAPE and modestly
curved/elongated forecast hodographs suggest supercell potential
exists in this area. An upgrade to a Slight Risk may be needed
pending guidance trends involving greater storm coverage.

Tropospheric flow across the southern to central High Plains will be
weaker compared to points farther north. However, the presence of a
dry boundary layer extending upward to at least 700 mb, amid 1000+
J/kg MLCAPE, should support some risk for dry downbursts with the
stronger storm cores, perhaps accompanied by an isolated severe gust
threat.

...Portions of the northern Great Basin to the central Rockies...
By afternoon peak heating, scattered high-based thunderstorms should
develop amid classic inverted-V profiles. Since these storms will
develop along the periphery of stronger flow aloft (driven by a
departing mid-level shortwave trough), some organization is
possible. Multiple dry microbursts may occur, some of which may pose
a severe gust threat. An upgrade to a Slight Risk may be needed if
guidance consensus trends upward in convective coverage.

...Maine...
By late morning into early afternoon, partially clearing skies will
encourage surface temperatures to rise into the 70s F, resulting in
marginal instability (e.g. a few hundred J/kg MLCAPE) given
relatively poor mid-level lapse rates. Nonetheless, a southerly mid-
to upper-level jet streak will overspread northern New England
during the afternoon, resulting in highly elongated hodographs and
30-40 kts of effective bulk (speed) shear. As such, any storms that
can develop and become sustained should become organized multicells
capable of supporting a few damaging gusts.

...Portions of the Gulf to Carolina coastlines...
By late morning into the afternoon, the heating of a very moist
boundary layer (e.g. 70s F surface dewpoints) will yield 2000-4000
J/kg MLCAPE, despite poor mid-level lapse rates. Once convective
temperatures are reached, several pulse storms and multicells will
develop, capable of producing wet downbursts and at least isolated
damaging gusts. Vertical wind shear will be locally stronger along
the NC coastline, where a supercell cannot be ruled out.

A consensus among CAMS depicts a relatively more organized cluster
of multicells emanating from a warm-air-advection regime across the
Ozark Valley, which will mature over southern MS into LA. Here,
there may be a locally denser cluster of damaging gusts, hence the
introduction of Category 2/Slight Risk severe wind probabilities.

..Squitieri.. 08/23/2026

$$