762
ACUS03 KWNS 181931
SWODY3
SPC AC 181930

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Tue Aug 18 2026

Valid 201200Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY ACROSS
PARTS OF THE MID ATLANTIC AND PARTS OF CENTRAL GREAT PLAINS INTO
UPPER MIDWEST...

...SUMMARY...
A few strong to severe storms are possible Thursday across parts of
the Mid Atlantic and north central Great Plains into Upper Midwest.

...Discussion...
In advance of weak, large-scale mid-level troughing slowly
approaching the Pacific coast, mid-level ridging may continue to
amplify northward through the northern U.S. and Canadian Rockies, to
the north of a prominent mid-level high slowly shifting northeast of
the Four Corners through this period.  Downstream, broad mid-level
troughing is forecast to begin to gradually shift to the north and
east of the Great Lakes and Northeast, but weak lingering troughing
upstream may continue dig southeast of the middle Mississippi/lower
Ohio valley toward the southern Appalachians.  One or two,
convective generated or augmented, perturbations may accelerate
northeastward out of the Ohio Valley through the northern Mid
Atlantic after emerging from the latter regime.  In their wake, it
appears that a surface frontal zone will continue a southward
progression, reaching the southern Mid Atlantic, northern Gulf
States and southern Great Plains Red River Valley by 12Z Friday.

Based on latest model output, convective potential through this
period still appears relatively limited, or at least uncertain due
to its dependence on sub-synoptic developments with low
predictability at this time frame.  As a result, the prior outlook
for this period has largely remained unchanged.

...Mid Atlantic/Southeast...
Latest model output suggests that stronger pre-frontal
destabilization to the east of the Appalachians may be confined to
the coastal plain, from northern North Carolina through the Delmarva
Peninsula.  Coupled with strengthening lower/mid-tropospheric flow
and forcing for ascent downstream of the approaching convectively
augmented perturbation, the environment may become conducive to
thunderstorms capable of producing damaging wind gusts.

...North central Great Plains into Upper Midwest...
A narrow corridor of stronger destabilization appears at least
possible ahead of a short wave perturbation digging within modest
northwesterly mid-level flow.  It is possible that this could become
sufficient to promote a risk for widely scattered strong storms with
potential to produce severe hail and wind late Thursday afternoon
into evening.

...Southwest...
Mid-level flow may transition to at least a bit more of a component
to the south of east during this period, but still potentially
conducive to propagation of convection off the higher terrain of
central and southeastern Arizona, given sufficient destabilization
in lower elevations.  This remains uncertain due to potential
impacts of convection Wednesday through Wednesday night, so will
hold off on adding low severe probabilities for wind at this time.

..Kerr.. 08/18/2026

$$