Day 1 Convective Outlook
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Issued: · Valid: –
Summary
Strong to locally severe thunderstorms capable of producing damaging wind gusts may develop across the south-central Plains into parts of the Midwest this afternoon and evening. Small hail may also occur during these storms.
Product Text
000 ACUS01 KWNS 150528 SWODY1 SPC AC 150526 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Tue Sep 15 2026 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL PLAINS INTO PARTS OF THE MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms may occur from the south-central Plains into parts of the Midwest this afternoon and evening, with at least isolated damaging wind gusts possible. ...South-central Plains into parts of the Midwest... A vigorous mid/upper-level trough will move quickly eastward across Ontario and the Upper Great Lakes region today, before reaching southern Hudson Bay and Quebec by this evening. A deep surface low will accompany this system, as a trailing cold front moves across parts of the central Plains and Midwest. To the south of the ejecting trough, an upper ridge is forecast to amplify over the Southeast. Persistent clouds and precipitation to the cool side of the front will help to reinforce the baroclinic zone as it moves southeastward through the day. The front will impinge on an increasingly warm and unstable environment by late afternoon, and scattered storm development is expected from the TX Panhandle into parts of the Midwest. The strongest mid/upper-level flow will be displaced north of the front, and low-level flow will tend to weaken through the day. This weakening flow regime, combined with gradual midlevel height rises and an eventual tendency for storms to be undercut by the front, results in uncertainty regarding the magnitude of the organized severe threat this afternoon and evening. However, seasonably strong heating and relatively large PW and buoyancy will support potential for localized downbursts and outflow-driven clusters, with attendant damaging-wind potential. Hail potential appears generally limited by weak midlevel lapse rates and only modest deep-layer shear, though small to near-severe hail may occur with the strongest cells. A relatively broad Marginal Risk has been maintained from the south-central Plains into the Midwest. Corridors of locally greater potential could eventually evolve within the broader risk area, especially near any pre-frontal outflow boundaries generated by early-day convection. ...Parts of UT/western CO... Anomalous moisture will remain in place across parts of the Four Corners region and Southwest today. The strongest deep-layer flow/shear will reside from UT into western CO, in advance of a mid/upper-level trough over the Pacific Northwest. While a few strong storms will be possible, generally weak heating and destabilization are currently expected to limit the magnitude of the severe threat. Small hail and gusty winds could accompany the strongest storms. ..Dean/Supinie.. 09/15/2026 $$