523
ACUS03 KWNS 130730
SWODY3
SPC AC 130729

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Thu Aug 13 2026

Valid 151200Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS INTO PARTS OF THE MIDWEST AND OHIO
VALLEY...SOUTHERN/CENTRAL APPALACHIANS...AND CAROLINAS...

...SUMMARY...
Strong to locally severe storms are possible on Saturday from the
central High Plains eastward into parts of the Midwest, Ohio Valley,
southern/central Appalachians, and Carolinas.

...Synopsis...
An upper ridge is forecast to remain anchored over parts of the
southern Plains and lower MS Valley vicinity on Saturday. A
warm-frontal zone initially extending from IA into the OH Valley is
forecast to move northward as a warm front, while the western
extension of this front may remain nearly stationary across the
central Plains. Farther north, a weak surface low is forecast to
move across northern MN, as a trailing cold front begins to move
southeastward across parts of the Dakotas and eventually into parts
of MN/IA/NE.

...Central High Plains eastward into parts of the Midwest/Ohio
Valley...
Another day of at least isolated severe potential is evident on
Saturday along the periphery of the upper ridge. However,
predictability is typically low regarding the details within this
regime, and generally modest midlevel lapse rates and deep-layer
shear may tend to limit the magnitude of severe potential. A broad
Level-1/Marginal Risk has been included where the greatest relative
severe potential is currently expected, though confidence in the
details is low.

Despite the relatively modest lapse rates, rich low-level moisture
will again support moderate to strong buoyancy near and north of the
front extending from the central High Plains into parts of the
Midwest/Ohio Valley. Given the generally modest deep-layer
flow/shear and nebulous large-scale ascent, any greater organized
severe potential may be dependent on optimally timed MCVs moving
along the periphery of the ridge.

Early-day convection across IA/MO may pose some severe threat,
especially if any storm cluster is able to propagate along the
frontal zone into parts of the OH Valley. Some guidance suggests
that an MCV may develop across the central High Plains late
D2/Friday and move east-northeastward across parts of NE/IA/southern
MN through the day Saturday, which may aid in storm development
near/north of the front during the afternoon/evening.

Farther west, diurnal storm development is again expected in the CO
Front Range vicinity, which could result in some storm clustering as
convection moves across the central High Plains Saturday night.
Given the favorable low-level moisture and buoyancy, the strongest
storms within any of these regimes could pose a threat for damaging
winds and perhaps isolated hail, though it is also possible that the
bulk of convection remains somewhat disorganized, due to relatively
weak deep-layer flow/shear.

...Southern/central Appalachians and Carolinas...
Modest northwesterly mid/upper-level flow will overspread a moist
and moderately unstable environment across parts of the
southern/central Appalachians and Carolinas during the afternoon. A
few stronger cells/clusters capable of damaging wind will be
possible within this regime.

..Dean.. 08/13/2026

$$