Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Wed Jun 24 2026
Valid 242000Z - 251200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE GREAT BASIN...HIGH PLAINS AND MIDWEST...
...SUMMARY...
Scattered severe thunderstorms are expected this afternoon and
evening across parts of the central High Plains, with a threat for
large to very large hail, severe wind gusts, and perhaps a couple of
tornadoes. Other severe thunderstorms are expected across parts of
the Midwest and Great Basin.
...20Z Update...
The forecast remains on track, and only minor adjustments were made
with this update. The ENH risk was expanded slightly southeastward
in southwestern NE. Here, diurnal heating amid lower 60s dewpoints
will yield a corridor of moderate surface-based buoyancy, which
combined with 50-60 kt of effective shear, will support the
potential for a couple intense supercells capable of producing very
large hail and severe gusts. The adjacent SLGT risk was also
expanded southeastward into south-central NE and north-central KS,
where upscale-growing clusters will pose a risk for severe wind
gusts with time.
The SLGT risk in eastern NM was expanded westward toward the higher
terrain, given the potential for initially discrete supercell
structures capable of producing large hail.
Finally, a CIG1 wind area was added over portions of the Great
Basin, where a deeply mixed boundary layer and increasing buoyancy
may support some gusts upwards of 75 mph.
..Weinman.. 06/24/2026
.PREV DISCUSSION... /ISSUED 1149 AM CDT Wed Jun 24 2026/
...Central/Southern High Plains...
Post-frontal low-level moisture will remain over the central High
Plains today via low-level upslope flow, which should be most
focused/strongest across southeast Wyoming/northeast Colorado, and
to a lesser extent, the Raton Mesa vicinity. As daytime heating
occurs and low-level clouds present this morning gradually erode,
2000-3000 J/kg of MLCAPE should develop by mid to late afternoon in
a narrow corridor across northeast Colorado into southeast Wyoming.
This instability will also be aided by the presence of steep
mid-level lapse rates.
Thunderstorms should develop this afternoon across much the region
as strong mid-level west-northwesterly flow associated with a
shortwave trough over the northern Plains overspreads the central
Rockies/High Plains. Accordingly, the highest convective coverage is
anticipated from east-central/southeast Wyoming into
northeast/east-central CO, where buoyancy should be maximized.
Deep-layer shear will be rather strong, with values up to 50-60 kt.
These conditions will support the potential for intense supercells
capable of large to very large hail (isolated 2-4 inches in diameter
possible). Notable low-level curvature of the hodograph could
support a couple of tornadoes in this region as well. Eventual
upscale growth into a southeastward-moving MCS capable of producing
severe winds is probable into eastern Colorado/western Kansas this
evening, with some 75+ mph gusts possible.
Lower thunderstorm coverage is anticipated farther south into the
southern High Plains, with warmer temperatures and higher cloud
bases suggesting a predominantly outflow-dominant mode. Strong to
severe gusts will be the primary risk, although isolated hail may
also occur.
...Midwest including portions of Wisconsin/northern Illinois...
A belt of 40-50 kt westerly mid-level flow will overspread Wisconsin
and northern Illinois today as a weak shortwave trough moves across
the Upper Midwest and Great Lakes through the period. Seasonably
cool temperatures aloft will aid up to around 1000-1500 J/kg of
MLCAPE through peak afternoon heating along/ahead of a weak cold
front. Current expectations are for scattered to numerous
thunderstorms to develop this afternoon with moderate to locally
strong deep-layer shear providing support for updraft organization.
A mix of multicells and supercells should pose a threat for severe
hail and damaging winds, and possibly some tornado risk, as they
spread east-southeastward through the afternoon and evening before
eventually weakening.
...Great Basin/Four Corners...
Current surface observations indicate rather dry conditions across
the Great Basin/Four Corners regions this morning. Still, greater
low/mid-level moisture is forecast to advect northeastward through
the day as a weak mid-level shortwave trough advances
east-northeastward from the lower Colorado River Valley across the
Great Basin. The boundary layer is expected to become very well
mixed with strong daytime heating that will occur this afternoon,
with weak instability present. Modestly enhanced mid-level flow will
aid in northeastward thunderstorm motions, and some potential exists
for strong/gusty outflow winds across a large area this afternoon
and early evening.
...Southern Plains into the Lower Mississippi Valley...
Thunderstorms should increase/re-intensify regionally this
afternoon, aided by multiple MCVs interacting with a convectively
augmented front that extends northwest-southeastward regionally.
Deep-layer flow and related shear should remain rather modest.
Isolated hail and damaging winds may occur with the strongest cores
that form, but the potential for more organized clusters is
uncertain. Influenced by prior/modifying outflow, at least a
conditional-type risk for supercell redevelopment later today is
most probable across portions of southern/eastern Oklahoma toward
the ArkLaTex.
...Florida...
After mostly clear skies this morning, cumulus field continues to
increase within a very moist air mass to the south of a front across
the northern Florida Peninsula, with low to mid 70s F warm-sector
surface dewpoints. While low/mid-level winds will remain weak today,
cool mid-level temperatures and ample daytime heating will support
the development of moderate to locally strong instability this
afternoon. Scattered to numerous pulse-type thunderstorms are
expected to develop across the interior Florida Peninsula and
Atlantic Coast sea breeze, with occasional damaging winds possible
given steepened low-level lapse rates.
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