164
ACUS48 KWNS 010830
SWOD48
SPC AC 010828

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0328 AM CDT Tue Sep 01 2026

Valid 041200Z - 091200Z

...DISCUSSION...
An upper ridge will meander from the Mid-MS and TN Valleys toward
the Plains through the extended period, with upper troughs poised to
amplify along the East Coast and over the Interior West. Multiple
mid-level impulses will traverse this flow pattern, translating from
the Pacific Northwest to the northern Plains and Upper MS Valley,
then the Mid-Atlantic. It is in this elongated, roughly zonal
corridor that thunderstorm potential will be highest.

The severe threat with the relatively highest degree of
predictability will be across the Mid-Atlantic Days 4-5 (Friday and
Saturday). On Friday, a diffuse differential heating boundary,
generated by thunderstorm clusters from previous days, will likely
become established somewhere across the southern Mid-Atlantic. As an
upper trough amplifies over this differential heating boundary,
thunderstorms should develop amid rich low-level moisture beneath
stronger flow aloft. The more organized storms may produce damaging
wind gusts (hence the maintenance of 15 percent severe
probabilities). Calibrated ML/AI guidance suggests that the severe
threat may persist into Saturday across the Carolina Piedmont.
However, deterministic guidance shows the upper trough advancing
further into the Atlantic this weekend, along with upper support. As
such, storm coverage and initiation mechanisms for Saturday remain
too unclear this far in advance for the introduction of severe
probabilities at this time.

Amplification of the Interior West upper trough will support surface
lee troughing and accompanying low-level moisture advection across
the Plains states. While at least isolated severe thunderstorms may
occur any where from the northern/central High Plains toward the
Upper MS Valley, predictability of any severe potential is too low
this far out.

..Squitieri.. 09/01/2026