016
ACUS01 KWNS 200102
SWODY1
SPC AC 200100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Wed Aug 19 2026

Valid 200100Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID
MISSISSIPPI AND OHIO VALLEYS AND SOUTHERN ARIZONA...

...SUMMARY...
Thunderstorms capable of severe wind gusts and hail remain possible
this evening across the mid Mississippi and lower Ohio Valleys and
southern Arizona. More isolated strong storms are possible through
the evening across parts of the central/southern High Plains and
parts of the Southeast.

...Mid MS Valley to the lower OH Valley.
Evening water vapor imagery showed a broad trough and enhanced
northwesterly mid-level flow stretching from the southern Dakotas
into the mid MS Valley. Downstream of a flattened upper ridge over
the Southwest, this trough and stronger flow aloft should continue
eastward this evening aiding in thunderstorm development across
parts of the Mid MS and lower OH valleys this evening.

Several clusters of storms are already ongoing this evening near a
diffuse frontal zone across MO and into southern IL and western KY.
As the upper trough approaches, ascent form a 30+ kt southwesterly
low-level jet may support an increase in storm coverage, possibly
along the flank of the exist cluster in MO and farther south along
the frontal zone later this evening. Moderate, and likely somewhat
elevated buoyancy (2000-3000 J/kg MUCAPE), and 40-50 kt of
deep-layer shear will favor organized clusters or supercell
structures. Hail is possible, along with some damaging winds and
perhaps a tornado, especially if storms can develop into a more
coherent MCS. These storms should spread eastward overnight into the
lower OH Valley with a continued severe risk.

...Central and southern High Plains...
Scattered thunderstorms, including a few supercells are ongoing
across the central and southern High Plains within a broad upslope
flow regime. Aided by an upper trough with moderate northwesterly
flow aloft, organized storms structures capable of large hail should
continue along the Foothills and adjacent high plains this evening.
Steep lapse rates and large temperature-dew point depressions may
also favor a few severe gusts with the more intense cores/clusters
that can develop.

...AZ...
Scattered storms across the higher terrain of southern AZ should
continue to move toward the southwest into the Lower Deserts this
evening. Adequate monsoon moisture amid very hot temperatures (100
F+) and steep low-level lapse rates will support strong downdrafts
with severe gusts of 60-75 mph possible.

...Southeast...
Scattered thunderstorms are ongoing early this evening from MS into
western/southern AL and across the FL Panhandle in association with
a weak MCV. A warm boundary layer and seasonably high moisture
content should continue to support scattered strong storms through
this evening. PWATs over 2 inches will favor strong water-loaded
downdrafts with isolated damaging gusts potential. Storms should
gradually diminish in coverage and intensity tonight as the boundary
layer stabilizes.

..Lyons.. 08/20/2026

$$