DES MOINES, IOWA — The Storm Prediction Center issued a Day 3 Outlook early Saturday morning placing a Marginal Risk for severe thunderstorms late Monday into Monday night across parts of the central Great Plains into the Upper Midwest, confirming and adding official weight to earlier private forecasts that had already flagged this same window for severe weather.
SPC Places a Marginal Risk for Late Monday Into Monday Night
The outlook, issued at 0714Z on September 12 by SPC forecaster Kerr, places a Marginal Risk, Level 1 of 5, across a stretch of the central Great Plains into the Upper Midwest, valid from 1200Z Monday, September 14, through 1200Z Tuesday, September 15. That window translates to roughly 7 a.m. Central time Monday through 7 a.m. Tuesday, with forecasters specifically flagging late Monday into Monday night as the period of greatest concern.
A Marginal Risk designation means isolated severe storms are possible across the highlighted zone, though widespread or intense severe weather is not currently expected as the setup evolves early next week.
Central Great Plains and Upper Midwest in the Crosshairs
The highlighted Marginal Risk area covers a stretch of the central Great Plains extending into the Upper Midwest, encompassing parts of the middle Missouri Valley region. That geographic footprint lines up closely with the corridor already being watched for Monday’s severe weather potential, reinforcing that this stretch of the country represents the primary area of concern as the new work week begins.
Residents across this region should treat late Monday afternoon into Monday night as a period requiring elevated weather awareness, given the confirmation now coming from SPC’s official outlook.
How This Confirms Earlier Forecasts for Monday
This SPC outlook lines up closely with earlier forecasts from private meteorologists, who had already been tracking a developing severe weather threat for the middle Missouri Valley and Upper Midwest tied to a weather disturbance and warm front expected to trigger storms late Monday afternoon and continue through the night. SPC’s official Marginal Risk designation adds government confirmation to what had previously been a private forecast signal.
That kind of alignment between private forecasting and SPC’s official categorical outlook typically increases confidence that the setup for Monday is genuinely taking shape as expected, rather than representing an isolated or uncertain signal from just one source.
What a Day 3 Marginal Risk Means This Far Out
Because this is a Day 3 outlook, issued more than two full days ahead of the actual threat window, some uncertainty remains around the exact placement, timing and intensity of any severe storms that develop. SPC will continue refining this outlook with updated Day 2 and Day 1 products as Monday approaches, potentially adjusting the shape or category of the highlighted zone based on new data.
For now, this early designation gives residents across the central Great Plains and Upper Midwest a multi-day heads up that late Monday into Monday night carries genuine severe weather potential, even if the finer details are still likely to evolve.
General Thunderstorm Potential Stretches Coast to Coast
Beyond the Marginal Risk zone, SPC’s outlook also shows a broad general thunderstorm potential extending across much of the country, stretching from the Pacific Northwest through the Rockies and Southwest, across Texas and the Gulf Coast, and up along the Eastern Seaboard. Storms within this much broader zone are not expected to reach severe criteria, but general thunderstorm activity remains possible across a wide stretch of the nation during the same overall period.
That widespread but lower-end thunderstorm coverage reflects a fairly typical mid-September pattern across much of the country, distinct from the more organized severe weather potential concentrated specifically over the central Great Plains and Upper Midwest.
What to Watch For as Monday Approaches
With both SPC’s official outlook and earlier private forecasts now aligned on late Monday into Monday night as the period of greatest concern, residents across the central Great Plains and Upper Midwest should continue monitoring updated forecasts through the weekend. As the event draws closer, expect SPC to issue more detailed Day 2 and Day 1 outlooks that will sharpen the exact geographic footprint and potential intensity of Monday’s severe weather threat.
In the meantime, this Day 3 Outlook offers a useful early planning tool for anyone across the central Great Plains and Upper Midwest with activities scheduled for late Monday or Monday night, giving a multi-day window to prepare before the more detailed, closer-range forecasts begin arriving over the next couple of days.
