835
ACUS48 KWNS 090809
SWOD48
SPC AC 090807

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 AM CDT Thu Oct 09 2025

Valid 121200Z - 171200Z

...DISCUSSION...
An upper anticyclone is forecast to remain over TX for much of the
Day 4-8 period, with attendant upper ridging oscillating between the
Plains and the MS Valley. An upper shortwave trough over the Rockies
on Day 4/Sun will lift northeast across the northern Plains into
Canada, along with a deepening surface low. As this occurs, a cold
front will sweep east across the northern/central Plains and the
Upper Midwest through Day 5/Mon. Modest boundary layer moisture
ahead of the front will support at least weak instability and
thunderstorm potential. However, severe thunderstorm chances appear
low given richer boundary layer moisture will remain offset from
stronger shear/large-scale ascent.

Another upper shortwave trough is expected to move from the Rockies
into portions of the Plains late in the forecast period. As this
occurs, lee cyclogenesis is likely to occur, and southerly low-level
flow may transport modest Gulf moisture northward into the central
Plains to the MO Valley. Some increase in severe thunderstorm
potential could develop around Day 7 or 8/Wed or Thu, from the
southern/central Plains toward the MO Valley. However, confidence is
too low to include severe probabilities at this time given poor
run-to-run model consistency.

..Leitman.. 10/09/2025