564
ACUS02 KWNS 181727
SWODY2
SPC AC 181726

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 PM CDT Fri Sep 18 2026

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY
AFTERNOON/EVENING FROM NORTHWEST OKLAHOMA INTO EASTERN KANSAS...

...SUMMARY...
Scattered severe wind and hail producing storms are likely across
portions of the central Plains, with more isolated severe storms
possible across the central High Plains, central Rockies, and the
Midwest to Southeast states tomorrow.

...Central Plains to the OH Valley...
North of a weakening midlevel high over the south central CONUS, a
belt of midlevel westerlies will be maintained from a shortwave
trough crossing ID/UT/WY/CO eastward to the central Plains and OH
Valley.  In associated with an embedded speed max, a weak surface
wave will develop eastward along a baroclinic zone from IA/IL to
northern OH by the end of the period.  The trailing cold front will
move slowly southeastward across the central Plains.  This front
will focus thunderstorm development Saturday afternoon/evening from
the eastern TX Panhandle across northwest OK into eastern KS.
Strong surface heating along and south of the front will drive
inverted-V profiles and moderate buoyancy (MLCAPE of 1500-2000
J/kg), which combined with ~30 kt midlevel flow will favor multicell
clusters with hybrid microbursts and occasional severe outflow
gusts.  Isolated large hail will also be possible with any more
organized storms moving along the front in a narrow zone of somewhat
enhanced vertical shear.

Farther east into the Midwest/OH Valley, the amplitude of the
surface wave and any associated low-level mass response will depend
on the degree of prior convective enhancement/MCV development.
Confidence is low in diurnal storm clusters evolving from morning
convection, though such a scenario could warrant higher wind
probabilities in later updates if a storm corridor can be identified
with more confidence. Forecast confidence is low so will maintain
low severe probabilities to reflect the potential for isolated wind
damage with embedded storm clusters across the OH Valley.  The
southern extent of the MRGL area (into AL) reflects the potential
for diurnal convection with isolated downbursts.

...Eastern CO/WY...
A weak low-level upslope flow regime and the approach of a midlevel
trough from the west will foster scattered thunderstorm development
Saturday afternoon near and immediately east of the higher terrain
from CO into WY.  Buoyancy and deep-layer vertical shear will be
sufficient for organized clusters and possibly a couple of
supercells with an attendant threat for isolated large hail and
strong-severe outflow gusts.  Convection will likely persist into
Saturday night while spreading toward western KS, though storms will
likely become slightly elevated and weaken with time.

..Thompson.. 09/18/2026

$$