Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Sep 16 2026

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE FRIDAY
AFTERNOON AND EVENING ACROSS PARTS OF NORTHWESTERN KANSAS...SOUTH
CENTRAL AND EASTERN NEBRASKA...ADJACENT SOUTHEASTERN SOUTH DAKOTA
...WESTERN AND CENTRAL IOWA...

...SUMMARY...
Strong thunderstorms may impact portions of the central Great Plains
through southern portions of the middle Missouri Valley late Friday
afternoon and evening, accompanied by at least some risk for severe
weather.

...Discussion...
A vigorous short wave trough in the westerlies is forecast to dig
across the northern Atlantic Seaboard accompanied by significant
surface cyclogenesis near and east of the Canadian Maritimes.  In
the wake of the cyclone, it appears that a cold front will continue
advancing offshore and through the southern Mid Atlantic Seaboard. 
A trailing low-level baroclinic zone may remain more or less
quasi-stationary across the lower Ohio and lower/mid Missouri
Valleys into northern high plains, beneath a weaker belt of
westerlies in the southern mid-latitudes.

Within this regime, a mid-level trough and embedded low are forecast
to slowly progress across the Intermountain West through Rockies
vicinity, preceded by a more subtle perturbation crossing the middle
Missouri Valley.  The latter impulse, and another westward migrating
wave across the Florida Peninsula vicinity may contribute to further
suppression of persistent mid-level ridging, which may otherwise
maintain a considerable influence across a shrinking corridor
centered across the southern Great Plains through Tennessee Valley.

...Central Great Plains through southern Mid Missouri Valley...
Convective potential remains uncertain for Friday through Friday
night.  However, latest model output suggests that the mid-level
perturbation overspreading the middle Missouri Valley will be
accompanied by a moderate jet including 30-40 kt southwesterly flow
in the 850-700 mb layer overspreading the central Great Plains
through upper Mississippi Valley.  

As insolation contributes to a more strongly heated and deeply mixed
boundary layer along modestly deepening surface troughing 
coincident with the low-level jet axis, there may be sufficient
moisture to support scattered thunderstorm development capable of
producing a few strong downbursts across parts of northwestern
Kansas through south central Nebraska late Friday afternoon and
evening.

Closer to a weak developing frontal wave near the Missouri River,
roughly between Omaha and Sioux City, seasonably high boundary-layer
moisture content along a warm frontal zone to its south may support
a corridor of sizable CAPE and potential for much more vigorous
thunderstorm development.  Lower/mid-tropospheric inhibition might
remain an issue concerning boundary-layer based thunderstorm
development, but a late afternoon/early evening supercell and small
upscale growing cluster do not appear out of the question, before
storms become elevated while spreading southeastward through
portions of central Iowa during the evening.

..Kerr.. 09/16/2026

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0356 AM CDT Wed Sep 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
Latest medium-range model output suggests that modest pre-frontal
surface troughing across the Texas/Oklahoma Panhandle vicinity
through south central/eastern Kansas, and perhaps the slow moving
frontal zone across northeastern Kansas through northern
Missouri/southeastern Iowa, may provide focus for scattered strong
thunderstorm development late Saturday afternoon into evening.  This
may be supported by forcing for ascent downstream of weak
larger-scale mid-level troughing slowly progressing across the
Rockies into Great Plains, with deep boundary-layer mixing along the
surface trough and higher boundary-layer moisture content along the
frontal zone contributing to thermodynamic profiles potentially
conducive to severe weather.  However, with the belt of stronger
lower/mid-tropospheric flow associated with a preceding impulse
tending to weaken and/or shift eastward near or to the south of the
Great Lakes region, it still appears that this potential will remain
relatively isolated in coverage and/or marginal in nature.

Thereafter, late this weekend through early next week, the spread
among model output concerning the mid/upper flow evolution
increases.  However, even among the differing solutions, there is
little readily apparent that indicates an increase in organized
severe thunderstorm potential.