ACUS01 KWNS 221632
SWODY1
SPC AC 221630

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat Aug 22 2026

Valid 221630Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS AND THE MID SOUTH...

...SUMMARY...
Scattered severe thunderstorms are possible over parts of the Mid
South with 60 to 75 mph gusts being the primary hazard.  Scattered
damaging winds are possible this afternoon across parts of the Ohio
Valley into the central Appalachians.

...Ohio Valley into the Central Appalachians and Tennessee/Lower
Mississippi Valleys...
An upper trough continues to dig southeast across the southwest
Great Lakes during the midday as a surface front advances slowly
east across the southern Great Lakes and OH Valley.  Late morning
surface analysis places a moist plume (65 to 70 deg F surface
dewpoints) extending northeastward ahead of the front from the lower
OH Valley into northeast OH.  Visible satellite imagery shows a
swelling cumulus field across the upper OH Valley where moderate
buoyancy has developed.  A gradual increase in thunderstorm coverage
and intensity is expected, with 20-30 kt of effective bulk shear
fostering enough updraft organization for multicell clusters capable
of producing scattered damaging winds.  See MCD #2081 for short-term
details.  These thunderstorms will spread eastward from the upper OH
Valley into the central Appalachians this afternoon and evening
before eventually weakening with eastward extent.  Isolated hail may
occur with the stronger cores that develop, but the poor mid-level
lapse rates present may limit this threat to some extent.  There
also appears to be some chance for strong to locally severe
thunderstorms to develop along/east of the Blue Ridge Mountains this
afternoon.  If this occurs, then occasional damaging winds would be
the main threat with this activity.

...Southern/Central Plains into the Mid South...
Satellite imagery late this morning shows a pair of convectively
enhanced mid-level vorticity maxima moving southeast over eastern
KS/OK on the eastern periphery of upper ridging centered over NM. 
Weak thunderstorm activity continues to progress southeast over
eastern KS towards the Ozarks, where the airmass has heated near 90
deg F to the downstream of greater cloud cover.  Surface analysis
this morning showed a reservoir of richer moisture (lower 70s deg F
surface dewpoints) south of a stalled west-east frontal zone. 
Additional heating/destabilization ahead of the southeastward-moving
thunderstorms and associated MCV will act to pre-condition the
environment to support a greater risk for severe gusts and wind
damage across parts of the Mid South this afternoon and early
evening.  CAM model guidance both from a model core and time-lagged
ensemble, suggest the eventual development of a linear cluster
developing over the Ozarks and moving east-southeast into a
hot/unstable airmass featuring very steep 0-3 km lapse rates.  Mid
to upper-level flow will tend to weaken with southeast extent, but
ample cloud-bearing shear for storm organization is evident.  Have
upgraded a corridor from northern ARK into northern MS where
confidence is highest on an MCS developing and an associated risk
for severe gusts and wind damage.  

Additional isolated storm development is expected later today across
parts of the southern Great Plains.  Moderate to locally strong
instability, very steep low-level lapse rates, and moderate
northwesterly deep-layer shear should support some
clustering/updraft organization.  Occasional hail and severe gusts
may occur as thunderstorms spread southward this afternoon/evening.

...Central High Plains/Front Range...
A separate area of convection is forecast to develop this afternoon
along the Front Range/Laramie Mountains in aweak post-frontal
low-level upslope regime.  While effective bulk shear should be
somewhat weaker across this region, a narrow corridor of greater
instability is forecast across the central High Plains. This may
support loosely organized multicells and marginal supercells with an
isolated severe hail/wind threat.  

...Great Basin/Northern Rockies into the Northwest...
Upper ridging will remain prominent from the Southwest into the
northern Rockies/High Plains today.  On the western periphery of
this ridging, an upper trough/low will move northward along/near the
coast of the Pacific Northwest.  Enhanced south-southwesterly
mid-level flow will overspread parts of the Great Basin, northern
Rockies, and Northwest through the period, with the strongest winds
forecast over WA/OR.  Low-level moisture remains fairly limited over
most of these regions, with somewhat greater surface dewpoints
present over parts of the Great Basin.

Diurnal heating should support modest destabilization and weak
instability from the northern Great Basin into the interior Pacific
Northwest and northern Rockies.  Thunderstorms will develop this
afternoon as the large-scale ascent preceding the upper trough/low
overspreads these regions in tandem with orographic effects across
the higher terrain.  Where low-level lapse rates can become
sufficiently steepened with a dry/well-mixed sub-cloud layer,
isolated severe/damaging winds may occur.  The overall severe threat
should be limited by weak instability.

..Smith/Chalmers.. 08/22/2026

$$