330
ACUS01 KWNS 011951
SWODY1
SPC AC 011949

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 PM CDT Thu Oct 01 2026

Valid 012000Z - 021200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN KANSAS/NORTHERN OKLAHOMA...

...SUMMARY...
Locally strong/gusty winds and perhaps a brief tornado or two may
occur this afternoon/early evening across parts of southern Kansas
into northwest Oklahoma and vicinity.

...20z Update...
Some trimming was done to the northwestern edge of the existing
Level 1/Marginal Risk area across southern Kansas where severe
probabilities have decreased in the wake of ongoing convection. See
MCD #2345 for additional short-term details.

Elsewhere, convective coverage has gradually increased over the past
hour across portions of south-central/south Texas amid hot and humid
conditions. A localized strong gust may occur with the strongest
downdrafts, but poor mid-level lapse rates and weakening deep-layer
flow/shear will limit overall convective intensity and preclude a
broader severe risk.

Recent HRRR/RRFS TLE data also suggest a low probability scenario
for an isolated stronger storm to develop along the surface frontal
boundary across northeastern Missouri/western Illinois later this
afternoon/evening. Poor mid-level lapse rates and limited available
buoyancy continue to suggest that the severity of any storm that can
develop is likely to remain muted, however.

..Chalmers/Thornton.. 10/01/2026

.PREV DISCUSSION... /ISSUED 1128 AM CDT Thu Oct 01 2026/

...Southern Kansas/Northern Oklahoma...
Recent surface analysis shows a weak low over northwest OK/the
northeast TX Panhandle, with a front extending northeastward from
this low across KS. A Pacific cold front also extends southward from
this low over the southern Plains. Cloud cover remains prevalent
over the warm sector across the southern/central Plains late this
morning, aided by lift associated with a mid/upper-level trough/low
centered over the southwest KS and the OK/TX Panhandles per latest
water vapor satellite imagery. While not a classic setup for
non-supercell tornadoes given modest low-level lapse rates and a
progressive cold front, there may still be a window for a brief
tornado or two this afternoon/early evening across parts of southern
KS into northwest OK and vicinity.

This area should generally warm into the 70s per recent RAP/HRRR
guidance, and even modest breaks in the cloud cover should support
some steepening of low-level lapse rates in an otherwise
vorticity-rich environment along/near both fronts. Current
expectations are for cells to develop over southwest KS/northwest OK
in the next couple of hours (by 18-20Z), with cool temperatures
aloft (around -10 to -11 C at 500 mb) aiding updraft strength in an
otherwise weak deep-layer shear environment. Small hail, strong to
locally severe winds, and perhaps a brief tornado could occur with
this activity until the southeastward-advancing cold front undercuts
convection by late afternoon/early evening.

...Texas/ArkLaTex into the Mid Mississippi Valley/Midwest...
Ongoing convection across central/north-central TX has remained
sub-severe through the morning. A rather moist low-level airmass
characterized by generally mid to upper 70s surface dewpoints is
present across east/coastal TX ahead of these thunderstorms. While
lapse rates aloft will remain poor (reference 12Z observed soundings
from FWD/DRT), some increase in instability is anticipated
downstream this afternoon with continued daytime heating.
South-southwesterly low/mid-level flow will continue to gradually
diminish through the day as the primary mid/upper-level trough
ejects northeastward across the southern/central Plains through this
evening. This will limit the degree of deep-layer shear available to
support organized updrafts and overall severe potential across the
ArkLaTex into east/south TX. That said, gusty winds may still occur
on a localized basis as convection spreads eastward across these
areas through the afternoon/evening.

Modestly enhanced mid-level flow and greater deep-layer shear will
be present this afternoon farther north into the mid MS
Valley/Midwest, as multiple subtle mid-level vorticity maxima spread
northeastward over these regions. However, both boundary-layer
instability and lapse rates aloft are forecast to remain rather
weak, which should limit updraft strength and overall severe
potential with northward extent across these areas.

$$