693
ACUS48 KWNS 310848
SWOD48
SPC AC 310846

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Mon Aug 31 2026

Valid 031200Z - 081200Z

...DISCUSSION...
An upper ridge will persist across the TN Valley this week before
retrograding to the Plains states and further amplifying into early
next week. As this occurs, upper troughing will also amplify along
the East Coast and Interior West. The best chances for severe storms
will be closer to the East Coast Days 4-5 (Thursday-Friday) as a
series of mid-level impulses will crest the Ridge and traverse the
Mid Atlantic, where instability will be present.

...Days 4-6 (Thursday-Saturday) - Mid-Atlantic Region...
The amplification of the broader upper trough along the East Coast
will result in a farther southward shift of accompanying mid-level
impulses, which will promote deep-layer ascent over the Mid-Atlantic
region. The severe threat may also be modulated farther south given
established baroclinic zones from prior rounds of storms. On
Thursday, storms should develop along a differential heating zone
somewhere around Delmarva or points immediately west. Surface
dewpoints in the upper 60s to near 70 F beneath seasonably cool
temperatures aloft will yield 1500-3000 J/kg MLCAPE. Given over 30
kts of effective bulk shear expected, multicells, supercells, and
short bowing segments will likely develop, accompanied by a severe
wind/hail threat.

For Day 5 (Friday), the upper trough will amplify further, allowing
for a surface differential heating zone to become established across
the southern Mid-Atlantic, where adequate moisture and instability
will likely coincide with modest vertical wind shear, supporting
another day of severe potential. Damaging gusts will likely be the
main threat.

Some lingering severe potential may exist across the Carolinas on
Day 6/Saturday before the upper trough departs the region, as
indicated by some ML/AI guidance. However, predictability on the
timing of details (i.e. baroclinic boundaries and overlapping
corridors of vertical wind shear) is too low for the introduction of
probabilities this outlook.

...Day 4 (Thursday) - Upper Midwest...
Some guidance depicts the potential for severe thunderstorms along
an effective warm front across portions of the Upper Midwest, where
rich low-level moisture will reside ahead of a surface trough. Given
stronger mid-level flow and cooler temperatures overspreading the
warm front, enough shear and instability may manifest to support a
severe threat. While calibrated guidance has been ramping up severe
probabilities over this area, synoptic features (such as a
pronounced mid-level impulse) do not appear strongly evident in
deterministic guidance, precluding the addition of severe
probabilities to this outlook.

..Squitieri.. 08/31/2026