TL;DR

The NOAA Storm Prediction Center (SPC) has issued an Enhanced Risk for severe thunderstorms across parts of the central High Plains today, June 24, 2026. Intense supercells are expected this afternoon and evening across northeast Colorado into southeast Wyoming, with large to very large hail (isolated stones up to 3 inches in diameter), severe wind gusts, and a couple of tornadoes all possible. Storms should initiate by mid to late afternoon and may grow upscale into a severe MCS capable of 75+ mph winds across eastern Colorado and western Kansas this evening. A separate Slight Risk covers portions of Wisconsin into northern Illinois, as well as parts of Utah.

Where is the highest risk today?

The Enhanced Risk area covers the central High Plains, specifically northeast Colorado and southeast Wyoming. This is where SPC forecasters expect the most intense supercell thunderstorms to develop this afternoon.

According to the SPC Day 1 Convective Outlook, "the highest convective coverage is anticipated from south-central/southeast WY into northeast/east-central CO, where buoyancy should be maximized."

Deep-layer shear values will reach 50-60 knots in this corridor, combined with 2000-3000 J/kg of mixed-layer CAPE (convective available potential energy) — the atmospheric fuel for thunderstorms. Steep mid-level lapse rates will further enhance storm intensity.

Cities and communities in or near the Enhanced Risk zone include:

  • Cheyenne, Wyoming
  • Fort Collins, Colorado
  • Greeley, Colorado
  • Boulder, Colorado
  • Denver, Colorado (western metro)

Farther south into the southern High Plains, thunderstorm coverage will be lower, with warmer temperatures and higher cloud bases favoring an outflow-dominant mode. Strong to severe gusts will be the primary risk there, with isolated hail also possible.

What are the primary threats?

SPC identifies three main hazards for the Enhanced Risk area today:

Large to very large hail

This is the primary threat. SPC warns that isolated hail up to 3 inches in diameter could fall from the most intense supercells. Hail of this size can cause catastrophic damage to vehicles, roofs, and windows.

Yesterday's severe weather across the region produced 97 hail reports, including multiple reports of baseball-sized hail (2.75 inches) near Wildorado, Texas. One report came from an NWS employee. Quarter to golf ball-sized hail was widespread across Texas, Colorado, Minnesota, and Oklahoma.

Severe wind gusts

As supercells mature this evening, SPC expects "eventual upscale growth into a southeastward-moving MCS capable of producing severe winds" across eastern Colorado and western Kansas. Some gusts of 75+ mph are possible with this organized line of storms.

Tornadoes

SPC notes that "notable low-level curvature of the hodograph could support a tornado or two in this region as well." While tornadoes are not the primary threat today, the combination of strong shear and adequate low-level moisture means a couple of tornadoes cannot be ruled out, particularly during the supercell phase before storms congeal into a line.

When will the storms hit?

Timing is critical today. Here's the expected timeline for the Enhanced Risk area:

  • Late morning through early afternoon: Low-level clouds present this morning should gradually erode as daytime heating occurs.
  • Mid to late afternoon: Thunderstorms should begin developing across northeast Colorado and southeast Wyoming as strong mid-level west-northwesterly flow associated with a shortwave trough overspreads the region.
  • Afternoon through evening: Supercells capable of very large hail and isolated tornadoes. This is the peak window for the most intense storms.
  • Evening into tonight: Upscale growth into a southeastward-moving MCS with severe wind potential across eastern Colorado and western Kansas.

Residents in the Enhanced Risk area should have multiple ways to receive warnings this afternoon and evening, and should be prepared to take shelter quickly if a Severe Thunderstorm Warning or Tornado Warning is issued for your location.

What about other regions?

Wisconsin and northern Illinois — Slight Risk

A Slight Risk covers portions of Wisconsin into northern Illinois today. SPC forecasts scattered to numerous thunderstorms this afternoon as a weak cold front moves through the region.

Moderate to locally strong deep-layer shear will support updraft organization, with a mix of multicells and supercells posing a threat for severe hail and damaging winds as storms spread east-southeastward through the afternoon and evening.

Around 1000-1500 J/kg of MLCAPE should develop through peak afternoon heating, aided by seasonably cool temperatures aloft. Extensive cloudiness this morning may delay heating to some extent.

Utah — Slight Risk

A Slight Risk for severe winds covers parts of Utah today. A weak mid-level shortwave trough will advance east-northeastward from the lower Colorado River Valley across the Great Basin, advecting greater low/mid-level moisture northeastward through the day.

Strong daytime heating will create a very well-mixed boundary layer with weak instability. Modestly enhanced mid-level flow will aid northeastward thunderstorm motions, with potential for strong/gusty outflow winds across a large area this afternoon and early evening.

Southern Plains into the Lower Mississippi Valley

Mainly elevated thunderstorms were ongoing this morning across northern Oklahoma and southern Kansas, likely aided by weak low-level warm advection. Radar imagery suggests this activity may be acquiring an MCV (mesoscale convective vortex) circulation.

This feature should track southeastward toward the ArkLaTex region through the day, generally along and north of a surface front stalled near the Red River. Eventual re-strengthening of convection may occur, with isolated hail and damaging winds possible with the strongest cores.

Farther south into the lower Mississippi Valley, additional thunderstorms may form this afternoon ahead of the ongoing convection in northern Louisiana in a moderately to strongly unstable airmass. Some loosely organized clusters could pose an isolated threat for damaging winds as they spread toward the central Gulf Coast through the early evening.

Florida Peninsula

Scattered to numerous pulse-type thunderstorms are expected to develop across the interior Florida Peninsula and along the Atlantic Coast sea breeze this afternoon. Cool mid-level temperatures and ample daytime heating will support moderate to locally strong instability.

Occasional damaging winds are possible given steepened low-level lapse rates, though low/mid-level winds will remain weak.

How to stay safe today

If you live in or will be traveling through the Enhanced Risk area today:

Before storms arrive:

  • Identify your shelter location now. A basement, interior room, or sturdy building away from windows is best.
  • Charge your phone and have backup power available.
  • Move vehicles into a garage if possible, especially given the very large hail threat.
  • Bring in or secure outdoor furniture, trampolines, and other items that could become projectiles in high winds.

When storms approach:

  • Monitor radar and warnings closely. SPC's Enhanced Risk means conditions are favorable for numerous severe storms, not just isolated cells.
  • If a Severe Thunderstorm Warning is issued for your location, treat it seriously. Warnings for very large hail or 75+ mph winds are life-threatening situations.
  • If a Tornado Warning is issued, move to your shelter immediately. Do not wait to see the tornado.

Nighttime tornado risk:

While the primary severe weather window is this afternoon and evening, the MCS moving into Kansas tonight could persist after dark. Tornadoes that occur at night are more than twice as deadly as daytime tornadoes, according to a 2008 peer-reviewed study in Weather and Forecasting, largely because people are asleep and may not receive warnings in time.

Third-party weather apps are silenced by Do Not Disturb mode on most smartphones, though Wireless Emergency Alerts (WEA) for tornado warnings still break through on most phones by default. If you're in the path of tonight's MCS and plan to sleep, consider additional alerting methods. VORTEX Pro places phone calls when a tornado warning is issued for a saved location — calls bypass Do Not Disturb, ensuring you wake up even if your phone is silenced.

If you're caught outside:

  • Do not try to outrun a tornado in a vehicle. If you see a tornado and cannot reach sturdy shelter, get into a ditch or low-lying area and cover your head.
  • If very large hail begins falling, pull over and cover yourself with anything available (blankets, floor mats, jackets). Do not exit the vehicle. Turn away from windows and get as low as possible.

What's driving today's setup?

Today's severe weather is being driven by a potent combination of ingredients across the central High Plains:

Instability: Post-frontal low-level moisture remains in place across the region. As low-level clouds erode and daytime heating occurs, steep mid-level lapse rates will allow CAPE values to climb to 2000-3000 J/kg in a narrow corridor.

Shear: A shortwave trough over the northern Plains is providing strong mid-level west-northwesterly flow, with deep-layer shear values reaching 50-60 knots. This is more than sufficient to support supercells.

Trigger: The shortwave trough itself will provide the lift needed to initiate convection this afternoon.

The overlap of strong instability, strong shear, and a clear trigger mechanism is what prompted SPC to upgrade portions of the High Plains to an Enhanced Risk — the third-highest category on the five-tier scale.

Tomorrow's outlook

SPC's Day 2 outlook (valid Thursday, June 25) shows a Slight Risk across portions of Oklahoma, Texas, Kansas, Ohio, Colorado, Wyoming, Pennsylvania, and New York, along with parts of the Southeast, Great Lakes, Ohio Valley, and Ozarks.

The Day 3 outlook (valid Friday, June 26) indicates a Marginal Risk across Oklahoma, Kansas, Missouri, Arkansas, the Northern Plains, and Ozarks.

Details on Thursday's severe weather potential will be available in tomorrow's outlook post.

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.