Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0745 PM CDT Fri Sep 18 2026

Valid 190100Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSOURI VALLEY...CENTRAL HIGH PLAINS AND INTERMOUNTAIN
WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts will be possible this
evening across parts of the mid Missouri Valley and Central High
Plains. A few severe wind gusts and hail may occur in parts of the
Intermountain West.

...Mid Missouri Valley...
An upper-level ridge is currently present in the central U.S, with a
30 to 40 knot low-level jet located near the ridge in the mid
Missouri Valley. Isolated thunderstorms have developed early this
evening in eastern Nebraska, near the axis of the low-level jet.
Surface dewpoints in eastern Nebraska are in the lower to mid 70s F,
with the RAP showing MLCAPE in the 1000 to 2000 J/kg range. While
the 00Z Omaha sounding has 0-6 km shear of 20 to 25 knots,
deep-layer shear is likely a bit stronger southward in the vicinity
of the low-level jet. This could be enough for an isolated
wind-damage threat. The threat may develop northeastward into
western and central Iowa this evening as low-level flow and
convective coverage both increase.

...Central Plains...
An anti-cyclonic flow pattern is present over much of the
north-central U.S. The eastern extension of a mid-level shortwave
trough, evident on water vapor imagery, is located over east-central
Colorado. Scattered thunderstorms are ongoing just ahead of the
trough from northeast Colorado into southwest Nebraska, where the
RAP has MLCAPE in the 1000 to 2000 J/kg range. The WSR-88D VWPs at
Goodland and Cheyenne have 0-6 km shear in the 30 to 40 knot range,
suggesting that an isolated severe threat will be possible early
this evening. Severe wind gusts will be the primary threat.

...Intermountain West...
On water vapor imagery, southwesterly mid-level flow is present from
the central Rockies into the central High Plains. A mid-level
shortwave trough appears to be located from near the Unita Mountains
in northeast Utah eastward into the central Rockies of Colorado.
Large-scale ascent associated with the trough is supporting
scattered thunderstorm development. The RAP shows the strongest
instability across northeast Utah and northwest Colorado, where
moderate deep-layer shear and modestly steep lapse rates are evident
on RAP analysis. This could be enough for an isolated potential for
severe wind gusts and hail over the next few hours.

..Broyles.. 09/19/2026

Day 3-8 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0450 PM CDT Fri Sep 18 2026

Valid 201200Z - 261200Z

...Discussion...
Weak upper troughing will enter the western CONUS on Day 3/Sunday as
a secondary decaying upper-level trough pushes into the central
Plains, bringing precipitation to the Northern Rockies and northern
Plains. Meanwhile, a southward progressing cold front and related
precipitation will bring some temporary relief to the southern
Plains through early next week. Residing high pressure over the
Southeast is expected to maintain hot and mostly dry conditions
across the lower Mississippi Valley through the middle of next week,
but prevailing light winds should suppress overall fire weather
concerns. Ensemble guidance is in general agreement for ridging to
build across the central-western CONUS late in the workweek as an
upper trough evolves in the eastern Pacific, indicating stronger
southwest winds could return to the Pacific Northwest and northern
Great Basin. However, an expected marginal fuelscape should limit a
broader fire weather threat.

..Elizalde-Garcia.. 09/18/2026

...Please see www.spc.noaa.gov/fire for graphic product...