RSS Mesoscale Discussions from Storm Prediction Center
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 PM CDT Thu Sep 18 2025
Valid 190100Z - 191200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING
INTO THE OVERNIGHT HOURS ACROSS PARTS OF THE LOWER MISSOURI VALLEY
INTO SOUTHERN GREAT PLAINS...AND ACROSS PARTS OF SOUTHERN/CENTRAL
ARIZONA...
...SUMMARY...
A couple of thunderstorms posing some risk for marginally severe
wind or hail remain possible across parts of the lower Missouri
Valley into southern Great Plains and across parts of the Southwest
tonight.
...01Z Update...
...Lower Missouri Valley...
A couple of stronger storms linger within a convective band aided by
forcing for ascent associated with one short wave trough slowly
pivoting north-northeastward into/through the lower Missouri Valley.
In general, though, convection is waning in intensity with the loss
of daytime heating, and these trends are likely to result in
increasingly negligible severe weather potential into mid/late
evening.
...Southern Great Plains...
Convection allowing guidance, among other model output, continues to
indicate that increasing thunderstorm development is still possible
late this evening into the overnight hours across parts of central
Oklahoma, perhaps supported by forcing for ascent aided by weak
lower/mid-tropospheric warm advection. As this occurs,
thermodynamic profiles and deep-layer shear might be conducive to a
couple of stronger storms posing at least some risk for marginally
severe hail and locally strong wind gusts.
...Southwest...
The boundary-layer remains very warm and deeply mixed across the
lower deserts of south central into central Arizona, where ongoing
north/northeastward propagating convection could still be
accompanied by a locally strong downburst or two through mid to late
evening.
..Kerr.. 09/19/2025
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