387
ACUS01 KWNS 171950
SWODY1
SPC AC 171949

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0149 PM CST Mon Nov 17 2025

Valid 172000Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST
ARKANSAS INTO CENTRAL MISSOURI AND FAR WEST-CENTRAL ILLINOIS...

...SUMMARY...
Scattered thunderstorms should occur this evening and overnight
across parts of the northern/central Plains into the Ozarks and mid
Mississippi Valley. Isolated thunderstorms are also possible across
the Southwest and central California. A few strong thunderstorms
capable of producing hail may occur across parts of Missouri and
western Illinois late tonight.

...20Z Update...
A few modest changes to the general thunderstorm forecast as well as
the Marginal in southwest MO/northwest AR based on recent
observation/trends in guidance. The forecast otherwise remains on
track. See the previous discussion for additional information.

..Wendt.. 11/17/2025

.PREV DISCUSSION... /ISSUED 1021 AM CST Mon Nov 17 2025/

...Ozarks into the Mid Mississippi Valley...
Shortwave trough currently moving across the central Rockies will
continue eastward across the central Plains, reaching the Mid MS
Valley by early tomorrow. Mass response ahead of this wave will
support continued low-level moisture advection, with low 60s
dewpoints likely reaching far southeast KS/far southwest MO by early
tomorrow morning. Mid 60s dewpoints will likely cover much of
eastern OK and western AR. The stronger large-scale ascent will
remain displaced west and north of the better low-level moisture,
and strong convective inhibition will preclude surface-based storms
throughout the period. However, persistent theta-e advection
throughout the warm conveyor will promote elevated buoyancy and the
potential for multiple rounds of elevated thunderstorms from the
Ozarks northeastward into the Mid MS Valley.

The initial round of deeper convection is expected across the
central MO vicinity this afternoon near the terminus of a 35-40 kt
low-level jet. Buoyancy will remain modest, but there is enough
shear within the cloud-bearing layer for updraft rotation and the
production of isolated hail. Continued warm-air advection will
result in further low-level warming and moistening, increasing the
elevated buoyancy tonight. This buoyancy coupled with glancing
large-scale ascent and a strengthening low-level jet could result in
additional thunderstorms farther south and west into southwest MO,
as well as increased coverage and intensity of any ongoing
thunderstorms from central MO into far west-central IL. Moderate to
strong vertical shear will continue to support rotation within any
deep and persistent updrafts, with an attendant threat for isolated
hail.

...CA into the Southwest...
Upper low currently off the northern CA coast will continue
southward throughout the day, ending the period over the San Luis
Obispo/Santa Barbara/Ventura county vicinity. Sporadic thunderstorms
are possible near this upper low, where cold mid-level temperature
and strong forcing for ascent are anticipated. A
non-lightning-producing band will move through the southern CA
coastal counties ahead of this low. Isolated lightning flashes are
also possible farther east within the warm conveyor over the Lower
CO River Valley and western AZ. Meager instability should limit the
threat for organized severe thunderstorms across the entire region.

$$