TL;DR

The NOAA Storm Prediction Center (SPC) has issued a Slight Risk for severe thunderstorms across three separate regions today: the southern Great Lakes and Midwest, the Ozarks into the Mid-South and Lower Mississippi Valley, and the central High Plains. Damaging winds will be the primary threat across all areas, with large hail also possible, particularly over the central High Plains. Storms will develop mid-afternoon and continue into the evening.

What's Driving Today's Severe Weather?

August 26, 2026 features a split-flow pattern with multiple weather systems driving thunderstorm development across a broad swath of the central and eastern United States. A mid-level shortwave trough over the upper Great Lakes is progressing eastward, while a remnant mesoscale convective vortex (MCV) tracks across the southern Plains. Meanwhile, modest upslope flow over the High Plains will aid storm initiation along the Front Range.

The common thread across all three risk areas: sufficient atmospheric instability combined with moderate wind shear to organize thunderstorms into damaging wind producers. While tornado potential remains limited due to veered low-level winds in most areas, the wind and hail threats are significant enough to warrant a Slight Risk designation across portions of at least a dozen states.

Yesterday saw widespread wind reports—75 in total—with scattered large hail across the Plains and Upper Midwest. No tornadoes were reported. Today's setup bears similarities, though the geographic focus has shifted somewhat eastward and southward.

Where Is the Highest Risk Today?

The SPC Slight Risk encompasses three distinct regions:

Southern Great Lakes and Midwest

A surface cold front will move east-southeastward across the Great Lakes and Midwest today, with thunderstorms developing along and ahead of the boundary between 19Z and 22Z (2–5 PM CDT). The corridor of highest concern stretches from eastern Illinois northeastward into southern Lower Michigan, where moderate instability will combine with 25–35 knots of deep-layer shear.

According to the SPC's Day 1 outlook, "a mix of multicell clusters and marginal supercells should pose a threat for both hail and damaging winds, with the wind threat potentially becoming the primary risk with eastward extent into the Midwest as thunderstorms grow upscale."

Lapse rates aloft remain somewhat poor, which may limit updraft intensity. Still, any storms that do organize will be capable of producing damaging gusts as they cluster and grow upscale through the evening. A brief embedded tornado is possible but not the main concern, as low-level winds are forecast to remain veered with limited hodograph curvature.

Ozarks Into the Mid-South and Lower Mississippi Valley

Thunderstorms developed this morning across southeast Missouri and far southern Illinois, tracking south-southeastward into the Mid-South. While initially sub-severe due to substantial mid-level convective inhibition (MLCIN), these storms may strengthen later today as the boundary layer destabilizes across western Tennessee, northern Mississippi, and northern Alabama.

Additional development is expected this afternoon along a weak surface front from southern Missouri into Arkansas and eastern Oklahoma. A remnant MCV moving eastward across the southern Plains will help focus convection. High precipitable water values—meaning abundant atmospheric moisture—will support robust downbursts with a scattered damaging wind threat.

The SPC notes that "some high-resolution guidance continues to show a southward-moving storm cluster across the lower MS Valley this evening/tonight. As such, there is potential for at least isolated damaging winds to persist across parts of southern LA/MS" into the overnight hours.

Occasional hail may also occur with the strongest cores given the degree of instability forecast, but wind remains the primary concern.

Central and Southern High Plains

Modest low-level upslope flow across the central High Plains will support convective initiation by early to mid-afternoon over the higher terrain and Front Range. Around 25–35 knots of west-northwesterly mid-level flow, combined with moderate instability and modestly steepened mid-level lapse rates, will aid updraft organization.

Both supercells and multicell clusters are possible, with both large hail and severe wind gusts likely as convection spreads east-southeastward through the afternoon and evening. There is some uncertainty regarding development farther east across southwest Nebraska along a front, but any storms that form in this area would also pose a severe risk.

Farther south across the southern High Plains, mid-level flow will be somewhat weaker. Still, convection developing across central and eastern New Mexico may become loosely organized and pose an isolated severe gust threat given the very well-mixed boundary layer. This threat may continue into the Oklahoma and Texas Panhandles through the evening before weakening.

When Will the Storms Hit?

Timing varies by region:

  • Great Lakes/Midwest: Storms develop 19–22Z (2–5 PM CDT) along and ahead of the cold front. The severe threat will likely diminish quickly this evening as convection outpaces low-level moisture and instability, and as nocturnal cooling occurs.
  • Ozarks/Mid-South/Lower Mississippi Valley: Morning storms across southeast Missouri and southern Illinois will continue tracking southward. Additional development is expected this afternoon along the front from southern Missouri into Arkansas and eastern Oklahoma. Isolated damaging winds may persist across parts of southern Louisiana and Mississippi into tonight.
  • Central High Plains: Initiation by early to mid-afternoon over higher terrain and the Front Range, with storms spreading east-southeastward through the afternoon and evening. Some potential for upscale growth and clustering into western Kansas this evening.

What Hazards to Expect

Damaging winds are the primary threat across all three Slight Risk areas. Yesterday's 75 wind reports underscore the active wind environment across the central United States, and today's setup favors a continuation of that pattern.

Large hail is also possible, particularly across the central High Plains where supercells may develop. Hail reports yesterday included 1.5-inch stones in Wisconsin and 1.25-inch hail in multiple locations across the Plains. Similar sizes are possible today, especially over the High Plains.

Tornadoes are not the main concern today. Low-level winds are forecast to remain veered across most areas, limiting the low-level shear necessary for tornadogenesis. The SPC mentions that "a brief embedded tornado may also occur" in the Great Lakes/Midwest region, but this is a low-probability scenario.

Heavy rainfall is likely given high precipitable water values, especially across the Ozarks and Mid-South. Localized flooding is possible in areas that see repeated storm development.

What Should You Do?

If you live in or near a Slight Risk area:

  • Monitor radar and warnings closely this afternoon and evening. Conditions can change quickly as storms develop and organize.
  • Have multiple ways to receive warnings. Wireless Emergency Alerts for severe thunderstorm and tornado warnings will break through Do Not Disturb mode on most smartphones. Third-party weather apps are silenced by Do Not Disturb, though Wireless Emergency Alerts for tornado warnings still break through on most phones.
  • Secure outdoor objects that could become projectiles in high winds—patio furniture, trampolines, and unsecured trash cans are common culprits.
  • Delay outdoor activities during the peak storm window, especially if you're in an area with limited shelter options.
  • If driving, pull over and wait out severe storms. Do not attempt to outrun a line of storms, and never park under an overpass during severe weather.

Tomorrow's Outlook

The SPC Day 2 outlook (valid Thursday, August 27) maintains a Slight Risk across portions of Nebraska, South Dakota, the Great Lakes, and the Northeast as the upper-level trough continues its eastward progression. Another round of organized severe weather is possible, though details will become clearer in tonight's updated outlooks.

The Day 3 outlook (valid Friday, August 28) shows a Marginal Risk across Georgia, the Central Plains, and Northern Plains as the pattern begins to shift.

VORTEX is a free web app at vortexintel.app that monitors severe weather nationwide. Pro ($4.99/month) places phone calls to your phone when a tornado or flash flood warning is issued for a location you care about — calls can ring through Do Not Disturb once you enable Emergency Bypass for the number, unlike most third-party app notifications.