Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Sat Aug 15 2026
Valid 151200Z - 161200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
OHIO VALLEY SOUTHEASTWARD INTO THE CAROLINAS...AND IN THE CENTRAL
HIGH PLAINS...
...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts will also be possible this afternoon
into the early evening from parts of the Ohio Valley southeastward
into the Carolinas.
...Mid Mississippi and Ohio Valleys/Central
Appalachians/Carolinas...
At mid-levels today, a broad anticyclonic flow pattern will be in
place over the eastern U.S. Within the flow, a shortwave trough will
move eastward into the lower Ohio Valley. Ahead of this feature, a
moist and unstable airmass will be located from the mid Mississippi
Valley east-southeastward into the Ohio Valley and southern
Appalachians. In the morning, a convective complex is forecast to
move eastward into the southern Great Lakes, and will likely be
associated with a potential for severe wind gusts. To the south of
this complex, a quasi-stationary front and moist axis will be
located from the lower Ohio Valley southeastward into the southern
Appalachians, along which moderate instability will develop by
afternoon. Low-level convergence near the front will be the focus
for convective development. A new complex of surface-based
thunderstorms appears likely to form near the front and move
east-southeastward from western Ohio into the Virginias during the
afternoon. Additional storms will develop along and near the
instability axis over the western Carolinas due to topographical
forcing.
Model forecasts in the moist air suggest that MLCAPE will peak in
the 2000 to 3000 J/kg range in most areas. Near the instability
axis, precipitable water values in the 1.8 to 2 inch range and
moderate deep-layer shear will likely support a threat for severe
wet downbursts. This threat should persist into the early evening
with any line segments that become sustained over the higher terrain
of the southern and central Appalachians.
...Central Plains...
West-southwesterly mid-level flow will be in place over the
southwestern and central U.S. today. At the surface, a moist airmass
will be located from the foothills of the Rockies eastward into the
central Plains. By afternoon, moderate instability will develop over
much of the region. Scattered thunderstorms will form in the higher
terrain and move eastward into the lower elevations during the mid
to late afternoon. Some RAP forecast soundings at 21Z from eastern
Colorado northward into western Nebraska have 0-6 km shear near 35
knots with steep low to mid-level lapse rates exceeding 7 C/km. This
environment will support a mixed mode with supercells and multicell
line segments possible. Supercells should be capable of isolated
large hail, while severe wind gusts will be possible with supercells
and organized multicells. The severe threat should persist into the
early to mid evening as a complex of storms moves eastward through
the central High Plains.
..Broyles/Lyons.. 08/15/2026
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