754
ACUS48 KWNS 150846
SWOD48
SPC AC 150845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0245 AM CST Sat Nov 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
Upper-level ridging over the Plains on Day 4/Tue will develop
eastward over the eastern third of the CONUS through Day 5/Wed as a
western upper trough slowly ejects over the Rockies and into the
Plains around Day 6/Thu. Gulf moisture will return northward across
the southern Plains and south-central states ahead of the ejecting
upper trough. Isolated strong to severe storms may be possible on
Wednesday across the southern Plains and Ozarks vicinity in a warm
advection regime ahead of the upper trough. By Day 6/Thu, the upper
trough should progress east across the Plains toward the Mississippi
Valley, with a surface cold front sweeping eastward as this occurs,
and some severe potential could accompany widespread thunderstorm
activity ahead of the front.

Confidence in coverage of severe storms Day 5-6/Wed-Thu is
uncertain. Large spread (and poor run-to-run consistency) exists
among forecast guidance. The GFS and ECMWF-AIFS are more similar
compared to the dynamical ECMWF, indicating a slower ejecting trough
and only modest surface cyclogenesis until late Thursday when the
low ejects northeast toward the Mid-MS Valley/Great Lakes.
Furthermore, while strong southwesterly flow will overspread
northward returning Gulf moisture across the Plains and
south-central states, forcing for ascent will be somewhat limited on
Wednesday as the trough ejects more slowly. As the trough ejects on
Thursday and a cold front becomes a focus for storm development,
boundary-parallel deep-layer flow and a northeastward ejecting
cyclone may favor a more anafrontal, training convection/heavy
rainfall scenario. While severe potential certainly is in play for
Days 5-6/Wed-Thu, these uncertainties preclude 15 percent
probabilities at this time.

Beyond Day 6/Thu, model disparity increases substantially and
predictability is low.

..Leitman.. 11/15/2025