598
ACUS48 KWNS 290857
SWOD48
SPC AC 290855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Sat Aug 29 2026

Valid 011200Z - 061200Z

...DISCUSSION...
Medium range guidance consensus depicts a persistent ridge fortified
across the central CONUS through the Days 4-8 (Tuesday-Saturday)
period. Multiple mid-level shortwave troughs and smaller scale
impulses will pivot around the broader upper ridge and traverse the
Pacific Northwest to northern Plains, Great Lakes, and Northeast
through the week. The best chance for rounds of organized strong to
severe thunderstorms will be with impulses overspreading a moist
boundary layer from the Upper MS Valley to the southern New
England/Mid-Atlantic regions. Details regarding the timing and
placement of some of these impulses varies among medium-range
guidance, rendering predictability too low for several potential
severe scenarios.

...Days 4-7 (Tuesday-Friday) - Northeast/Mid-Atlantic...
The Northeast to Mid-Atlantic will experience the east-northeast
periphery of the aforementioned upper ridge, with multiple impulses
expected to overspread the region through the middle of the week. At
least isolated to scattered severe thunderstorms are expected each
day Tuesday-Friday. At the moment, medium range guidance consensus
shows the strongest signal in a mid-level impulse impinging on
southern New England and the Mid-Atlantic on Day 5/Wednesday, where
severe probabilities have been maintained.

Guidance also depicts these same regions to have adequate vertical
wind shear and instability Tuesday and Thursday, perhaps even
extending into Day 7/Friday. Like Wednesday, several members of
medium range ML/AI generated guidance also has severe probabilities
over these regions Days 4-7. Unlike Wednesday though, deterministic
medium range guidance varies in place and time of the more subtle
impulses expected to support severe weather over the Northeast. It
is acknowledged that severe probabilities will likely be needed in
the future. However, probabilities have been withheld outside of
Wednesday out of prudence given the degree of changes in forecast
details expected in the coming days.

..Squitieri.. 08/29/2026