SPC Aug 22, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


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 a weak 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


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SPC Aug 22, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0702 AM CDT Sat Aug 22 2026

Valid 221300Z - 231200Z

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

...SUMMARY...
Thunderstorms capable of producing scattered damaging winds should
occur this afternoon across parts of the Ohio Valley into the
central Appalachians, with isolated damaging winds possible across
the lower Mississippi Valley to the southern Plains/Ozarks. Isolated
hail and damaging winds may also occur over parts of the central
Plains and northern Rockies into the Northwest.

...Ohio Valley into the Central Appalachians and Tennessee/Lower
Mississippi Valleys...
Upper troughing over Ontario and the Great Lakes will advance slowly
eastward today across the OH Valley/Midwest in tandem with a weak
surface cold front. Latest visible satellite imagery this morning
shows mostly clear skies present across the upper OH Valley
vicinity. While low-level moisture will remain fairly modest
(surface dewpoints generally in the 60s) and lapse rates aloft will
be near moist adiabatic, it still appears likely that around
1000-2000 J/kg of MLCAPE will develop ahead of the front by early
afternoon. 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. 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.

There may be less thunderstorm coverage with southwestward extent
along/ahead of the front into the TN Valley/Mid-South, as
large-scale ascent will be weaker across these regions. Still, any
convection which can develop and be sustained will exist in a
favorable environment for damaging winds, with moderate to strong
instability and sufficient deep-layer shear present to support
multicell clusters.

...Southern/Central Plains into the Ozarks...
On the eastern periphery of upper ridging over the
Southwest/Rockies, thunderstorms have developed early this morning
across parts of the southern/central Plains. This convection is
being aided by modest low-level warm/moist advection, and multiple
weak mid-level disturbances moving through the northwesterly
mid-level flow across the Plains. While substantial MLCIN is
present, sufficient MUCAPE coupled with moderate to strong
deep-layer shear should continue to support updraft organization.
Isolated hail and strong to locally severe gusts may occur with the
more robust cores, and severe probabilities have been adjusted to
account for ongoing convection. Subsequent development of
thunderstorms this afternoon will be dependent on how this morning's
convection evolves, with some weakening possible as a modest
low-level jet gradually lessens over the next several hours. Still,
redevelopment is forecast this afternoon along/south of a weak
front. 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 across the
southern Plains/Ozarks this afternoon/evening.

A separate area of convection is forecast to develop this afternoon
along the Front Range/Laramie Mountains in a weak 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 supercell
structures with an isolated severe hail/wind threat. This activity
should spread slowly southeastward off the higher terrain before
weakening this evening with the loss of daytime heating.

...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.

..Gleason/Broyles.. 08/22/2026


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SPC Aug 22, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Sat Aug 22 2026

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER OHIO VALLEY...

...SUMMARY...
Scattered damaging gusts are likely across the Ohio Valley with more
isolated damaging wind potential extending westward into the Mid
Mississippi Valley and southern Plains this afternoon/evening.
Isolated hail and damaging winds are also possible over the Front
Range, Great Basin and parts of the northern Rockies.

...OH and TN Valleys...
An upper low initially over the western Great Lakes is forecast to
deepen as it moves southeastward today and tonight. A belt of
stronger mid-level flow behind the trough will move into parts of
the Plains and Midwest. A weak surface low and trailing cold front
will move southeastward across the Lakes and into the upper OH
Valley through the day. Ahead of the front, upper 60s to 70s F
surface dewpoints and filtered diurnal heating should allow for
moderate destabilization, sufficient for scattered to numerous
thunderstorms by early afternoon. Despite generally modest to weak
deep-layer shear, steepening of lower/mid-level lapse will support
stronger downdrafts within organized multicell clusters. With time,
some upscale growth into linear segments is also possible and would
also favor a risk for scattered damaging gusts. This appears most
likely across central/eastern OH and KY into western PA/WV.

Farther south, more isolated storm coverage is expected ahead of the
front from the western Carolina Piedmont to the TN Valley. Steep
low-level lapse rates and enhanced low and mid-level northwesterly
flow will still support some risk for isolated damaging gusts.

...Ozarks/Mid MS Valley...
A weak convectively augmented shortwave trough is forecast to move
from southeastern KS and southern MO into northern AR along western
portions of a weak surface front by midday. Ahead of these features,
a very warm and humid air mass will be in place, which should allow
substantial diurnal destabilization and eventual thunderstorm
development. Enhanced northwesterly flow may help organize a few
thunderstorm clusters as they spread eastward from the Ozarks into
the ArkLaTex and mid MS Valley. Damaging wind gusts and some hail
are possible.

...Front Range and adjacent High Plains...
Post-frontal upslope flow, aided by a weak short wave impulse on the
eastern periphery of the upper ridge will support thunderstorm
development along/east of the Laramie mountains through Colorado
Front Range this afternoon. On the fringes of the stronger northwest
flow aloft, deep-layer shear will be marginal for storm
organization. Steep mid-level lapse rates and moderate buoyancy
could support some hail with the stronger updrafts. Isolated
damaging gusts are also possible, especially with any more
persistent thunderstorm clusters.

...Southern Plains...
Very hot surface temperatures (100+ F) are likely across parts of
western North TX into southwestern and central OK this afternoon.
Low-level convergence near a thermally enhanced surface low and weak
front will aid high-based thunderstorm development late afternoon
into the early evening. Weak buoyancy atop the steep low-level lapse
rates and deep mixed layer will favor very strong downdrafts within
the high-based storms. Isolated severe gusts (possibly 65-75 mph
gusts) associated with microbursts are possible as convection is
forecast to move southward through the evening.

...Northern Rockies to the Great Basin....
An upper low along the western periphery of the substantial
mid-level ridge over the Southwest will migrate northward toward the
international border as a belt of stronger mid-level flow
overspreads a plume of monsoon moisture from the Great Basin to the
Northern Rockies. Ascent from the upper wave and heating of the
modestly moist air mass should allow for weak destabilization and
scattered thunderstorm development. Steep lapse rates could support
isolated severe gusts.

Isolated hail is also possible with scattered thunderstorms from
eastern WA into the ID panhandle. Closer to the upper trough and
beneath strong mid-level flow, elongated hodographs may promote
organization with transient supercell structures. Cooler mid-level
temperatures could favor hail production despite modest overall
moisture.

..Lyons/Weinman.. 08/22/2026


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SPC Aug 21, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Fri Aug 21 2026

Valid 212000Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...MIDWEST...LOWER MS VALLEY...AND CAROLINAS...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds may occur over parts of the central
Plains into the Midwest this afternoon and evening. Damaging winds
also remain possible with scattered to numerous thunderstorms across
portions of the Carolinas and northern Gulf Coast states.

...20z Update...

...Lower MS Valley and Carolinas...
The forecast generally remains on track with only a minor eastward
expansion of the 15% wind probabilities in southern Alabama and the
far western Florida Panhandle. Modestly stronger low-to-mid level
flow (evident in the MOB VWP) and favorable thermodynamic profiles
(steep low-level lapse rates and high PW) should support stronger
downbursts and scattered damaging wind gusts, similar to areas
farther east. See Mesoscale Discussion #2069 for additional
short-term details.

...Midwest...
The Level 1/Marginal risk and Level 2/Slight risk areas were
expanded slightly northwestward based on observed convective
development ongoing across as of 1945 UTC across southwestern
Wisconsin. Some consideration was given to adding a targeted 5%
tornado probability area along the remnant outflow boundary
extending from southeast of Rockford, IL, into southwestern
Wisconsin; however, uncertainty regarding the longevity of a
supercellular storm mode (owing to the potential for cell
mergers/interactions) and the presence of only modest low-level
hodograph curvature/SRH precludes a 5% area at this time. See
Mesoscale Discussion #2070 for additional short-term details.

...Central Plains...
Latest high-res guidance has poorly captured the evolution of
morning and ongoing convection across portions of central and
eastern Nebraska through early this afternoon, which lends
uncertainty to the evolution of the severe threat through the rest
of the period. Given the continued potential for ongoing convection
to intensify and/or for additional redevelopment through the
evening, however, severe probabilities have been maintained with
only minor expansions made to the CIG1 wind and hail areas.

...Northern Great Basin into the Snake Valley...
Convective development is ongoing across portions of central/eastern
Nevada, with thunderstorms forecast to evolve northward through the
afternoon. The 5% wind probabilities and CIG1 area were expanded
westward and northward based on the placement of ongoing
thunderstorm activity and the latest HRRR/RRFS runs.

..Chalmers/Moore.. 08/21/2026

.PREV DISCUSSION... /ISSUED 1124 AM CDT Fri Aug 21 2026/

...Central Plains into the Midwest...
A northwest flow regime will result in a weakly forced and in a
limited confidence severe setup across the central Plains. Ongoing
widely scattered storm activity may persist and reinvigorate during
the afternoon, or new development occurs along residual outflow as
the airmass becomes moderately to strongly unstable. Forecast
sounding profiles show moist low levels beneath steep 700-500 mb
lapse rates amid veering and strengthening flow with height. Large
hail (some 2+ inches) would be a threat with any sustained
supercells along with severe gusts (60-75 mph). If a small cluster
can eventually develop, the severe-wind hazard would likely focus
with these potential storms.

A small west to east oriented band of storms is moving south across
southern WI to the east of a weak surface low and immediately
downstream of an associated mid-level perturbation. While effective
bulk shear is forecast to remain fairly modest (around 20-30 kt), a
mix of multicells and marginal supercells is expected to develop
later this afternoon across parts of southern WI into
northern/central IL along and ahead of a weak front. Severe hail
may occur with any persistent cells, while the threat for damaging
winds should increase as small clusters form and spread
east-southeastward through the early evening. While low-level
flow is not forecast to become overly strong, sufficient veering
with height through low/mid levels should exist to support modest
low-level hodograph curvature and some risk for a brief tornado.

...Carolinas...
Weakened shower/thunderstorm activity associated with an MCV over
the western Carolinas will likely dissipate during the early
afternoon. However, renewed storm development is forecast in
proximity to this upper disturbance, as well as near residual
outflow from the earlier convection and a surface cool front draped
from the GA/SC Piedmont northeastward into the coastal plain of
eastern NC. Strong heating of a seasonably moist boundary layer
will result in strong instability by mid afternoon. Sufficient
deep-layer shear for some organized multicell potential will be
greatest near the upper-level feature. Farther southeast near the
SC Low Country, weaker flow will result in a pulse thunderstorm
mode. Scattered damaging gusts are possible with the stronger
thunderstorms through the early evening before nocturnal stability
weakens storms and ends the severe threat.

...North TX east into northern Gulf Coast states...
Antecedent outflow from overnight storm clusters over the lower MS
Valley and AL will serve as a focus for storm development this
afternoon. Farther west, a more pronounced decaying MCS and
associated southward-moving MCV over east-central OK will also focus
storm activity across east TX into western LA. The 12 UTC Little
Rock raob showed a belt of enhanced flow around the 4-5 km layer
(35-40 kt). Other than a localized corridor where moderate
northerly flow will overspread a strongly destabilizing boundary
layer, slightly weaker northerly to northeasterly flow will
encompass this larger region from north TX to Mobile Bay.
Nonetheless, the development of very steep 0-3 km lapse rates (9 deg
C/km) by early to mid afternoon and high PW (1.75-2.0 inches) will
support scattered wind damage with the more intense downdrafts (most
likely and concentrated from east TX through southern MS).

...Northern Great Basin into the Snake Valley...
A mid-level vorticity max rotating northward around the western
periphery of the Four Corners upper high, will move into northern
NV/UT by late afternoon. Deep inverted-V profiles will develop by
mid afternoon with a dry sub-cloud layer featuring large surface
temperature-dewpoint spreads. A linear cluster of storms is
expected to evolve and move north across the NV/UT/ID vicinity
during the late afternoon and early evening. Evaporatively cooled
downdrafts will be potentially capable of severe gusts 60-75 mph.


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