474
ACUS48 KWNS 100746
SWOD48
SPC AC 100744

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0244 AM CDT Thu Sep 10 2026

Valid 131200Z - 181200Z

...DISCUSSION...
...Days 4-5/Sun-Mon -- Central Plains to the Mid-MS Valley...

A progressive upper pattern is expected early in the week. An
initial upper trough over the Great Lakes will spread east as upper
ridging builds across the Plains. Meanwhile, another upper trough
over the Northwest will shift east, moving across the northern
Plains and Upper Midwest on Monday, breaking down the upper ridge.
Surface high pressure over the Great Lakes on Sunday will suppress
low-level moisture southward across the central/southern Plains and
the Mid-MS/Lower OH Valleys. A very moist airmass will be in place
to the south of a stalled frontal boundary across the region.
Widespread showers and thunderstorms will be possible near the
surface boundary within low-level warm advection over the Middle to
Lower MO Valley. Vertical shear will be weak, but strong instability
could some strong gust potential, though convection may stay mainly
to the cool side of the surface boundary. Overall, severe potential
appears less than 15 percent on Sunday.

Severe potential will likely increase on Monday as the upper ridge
breaks down and stronger southwesterly flow overspread the
northern/central Plains to the Mid/Upper MS Valleys. Rich boundary
layer moisture will be in place ahead of a southeastward-advancing
cold front. Convection may be ongoing from the northern Plains into
IA/IL Monday morning. This results in some uncertainty in position
of best severe potential. Currently, the best overlap of rich
boundary layer moisture, strong instability and favorable shear near
the advancing cold front appears to be from eastern NE into IA and
vicinity. A 40+ kt southwesterly low-level jet is expected to
develop during the nighttime hours across KS/NE into IA, oriented
along the surface front, supporting an organized line of storms
tracking southeast ahead of the front, and promoting damaging wind
potential. Overall, the pattern appears favorable for at least
isolated severe storms on Monday, and a 15 percent delineation has
been included.

...Days 6-8/Tue-Thu...

The early week surface front will stall from the southern Plains to
Mid-MS/Lower OH Valley through mid-week. A very moist airmass will
persist south of the boundary, and persistent low-level warm
advection could favor bouts of heavy rain. While some low-level
severe potential could develop where pockets of strong
destabilization occurs, weak vertical shear should largely limit
more widespread potential, precluding probabilities.

..Leitman.. 09/10/2026