800
ACUS01 KWNS 220104
SWODY1
SPC AC 220102

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Fri Aug 21 2026

Valid 220100Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL PLAINS AND MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds should continue over parts of the
central Plains into the Midwest this evening. Isolated damaging
winds also remain possible across portions of the Carolinas and
northern Gulf Coast states.

...Central Plains...
Evening water-vapor imagery showed a subtle mid-level perturbation
embedded within a broad corridor of northwesterly flow aloft
overspreading much of the central US. isolated storm development has
taken place along the western portions of a stalled front over
western NE. South of the front, very warm and humid conditions have
allowed for strong destabilization over much of the central Plains.
Robust deep-layer shear profiles are favorable for supercells with a
risk for large to very large hail, damaging gusts and perhaps a
tornado persisting this evening.

Additional development is possible along the stalled front farther
east late this evening with a forecast increase in the low-level
jet. Initial supercell structures are possible with hail and could
grow upscale into one ore more clusters with a risk for damaging
gusts through the overnight hours.

Isolated higher-based storms ongoing in eastern CO may persist for a
few hours this evening owing to very warm surface temperatures and
steep low/mid-level lapse rates. Located on the fringes of the more
robust buoyancy, isolated severe gusts or hail are possible as they
drift slowly southeastward.

...Midwest...
Beneath the upper trough over the Great Lakes, isolated to widely
scattered thunderstorms have developed ahead of the southward moving
cold front and remnant outflow boundary from southern WI into
eastern IA and northern IL. Large buoyancy (2000-3000 J/kg MLCAPE)
is in place within a warm and very moist air mass. Modest
enhancement of the mid-level flow is also supporting elongated
hodographs sufficient for storm organization. A mix of supercells
and multicells should continue for a few hours this evening with a
risk for hail and damaging gusts. A tornado or two also remains
possible where backed low-level flow is supporting stronger shear
across southeastern IA and northern IL.

...Carolinas...
Numerous thunderstorms developed along a frontal boundary across the
Carolinas this afternoon. These storms have gradually clustered and
produced numerous instance of wind damage. Given the extent of the
convection, much of the available buoyancy has been removed and much
of the convection has slowly weakened early this evening. Still,
some lingering instability along the coast should support storms for
a few hours this evening. High PWAT content and modest enhancement
of mid-level flow from a weak MCV may support some isolated damaging
wind gusts.

...Gulf Coast/Lower MS valley...
Numerous thunderstorms are ongoing ahead of a weak surface cold
front slowly moving southward along the lower MS Valley and central
Gulf Coast. Very warm temperatures within the seasonably humid air
mass are supporting moderate to large instability (2500-3500 J/kg of
MLCAPE). This will be more than sufficient to maintain strong to
severe storms within the ongoing clusters. Clustering and high PWAT
content (1.75-2.3 inches) will support isolated wind damage with the
more intense downdrafts for a few more hours this evening before
they eventually move offshore or weaken after sunset.

...Northern Great Basin...
Evening water-vapor imagery showed an upper trough moving from south
to north along the western periphery of a strong upper high centered
over the central Rockies. On the eastern periphery of this trough,
scattered thunderstorms are ongoing over parts of NV and western UT.
Monsoon moisture is supporting weak to moderate buoyancy atop steep
low-level lapse rates. The ongoing storms, with some clustering, are
expected to continue and move northward across the NV/UT/ID vicinity
through this evening. Deep inverted-V profiles and a dry sub-cloud
layers will favor strong downdrafts, potentially capable of severe
gusts 60-75 mph.

..Lyons.. 08/22/2026

$$