Post sponsored by

Source: US National Oceanic and Atmospheric Administration

Day 4-8 Severe Weather Outlook Issued on Aug 27, 2019
Updated: Tue Aug 27 09:00:03 UTC 2019


Fri, Aug 30, 2019 – Sat, Aug 31, 2019
Mon, Sep 02, 2019 – Tue, Sep 03, 2019
Sat, Aug 31, 2019 – Sun, Sep 01, 2019
Tue, Sep 03, 2019 – Wed, Sep 04, 2019
Sun, Sep 01, 2019 – Mon, Sep 02, 2019
(All days are valid from 12 UTC – 12 UTC the following day)

Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.

 Forecast Discussion

ACUS48 KWNS 270858
SPC AC 270858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Tue Aug 27 2019

Valid 301200Z – 041200Z

…Days 4/5 – Fri/Sat — Central and Southern Plains Vicinity…

At least some potential for strong to severe storms appears possible
heading into the weekend as a stalled cold front in the vicinity of
southern NE/northern KS progresses southward as an upper shortwave
impulse shifts southeast across the northern Plains and Upper
Midwest. Southerly low level flow will continue to bring rich Gulf
moisture northward across the southern/central Plains. At this time,
aside from the surface boundary, forcing for ascent appears weak as
does forecast shear. Guidance also varies in location/timing and
extent of convection. As a result, uncertainty is too great to
include severe probabilities at this time.

…Days 5/6 – Saturday/Sunday — Southeastern U.S…

By late Saturday into Sunday, some guidance brings current Tropical
Storm Dorian toward Florida. Depending on the exact track, this
could bring an attendant tropical cyclone tornado threat to portions
of the southeastern U.S. Trends will be monitored closely along with
future collaboration with the National Hurricane Center to address
any possible threats approaching the mainland U.S. in the coming

…Days 7/8 – Monday/Tuesday — Northern/Central Plains to the Upper

By the end of the period, forecast guidance brings a shortwave
trough across the northern Rockies toward the northern Plains. A
strengthening lee surface low over the northern High Plains and
attendant cold front will shift east/southeast and could be a focus
for severe potential early next week. Questions remain regarding
moisture return this far north as well as timing differences in the
arrival of the trough and surface cold front. As such, confidence is
too low to introduce severe probabilities.

..Leitman.. 08/27/2019