Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 AM CDT Sun Jul 26 2026
Valid 261300Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
UPPER MIDWEST/GREAT LAKES...
...SUMMARY...
Severe thunderstorms capable of large to very large hail, damaging
winds (possibly 75+ mph), and tornado risk are expected from the
upper Mississippi Valley and Great Lakes southwestward into
Nebraska, mainly this afternoon and tonight.
...Upper Midwest and Great Lakes...
Have upgraded portions of the region to an Enhanced Risk including
Wisconsin and nearby far eastern Minnesota and Upper Michigan. An
upper ridge will remain anchored from the Southwest into the
central Rockies and High Plains through tonight. Seasonably
strong northwesterly flow aloft will overspread a very warm, moist,
and unstable environment from parts of the Upper Midwest and Great
Lakes into the central Plains.
Aided by favorably-timed MCV/mid-level impulse, the most likely
initiation zone for diurnal storm development is expected to be
across northern Minnesota into Wisconsin. Initial intense supercell
development is expected in this zone, posing a threat of large to
very large hail, localized severe wind gusts, and potentially at
least some tornado risk. Upscale growth into one or more intense
wind-producing southeastward-moving clusters are expected into this
evening amidst the enhanced northwesterly flow aloft.
...Middle Mississippi Valley...
Residual MCV influences may semi-focus renewed thunderstorm
development into a very unstable environment this afternoon
regionally, with potential storm organization aided by semi-strong
mid/high-level winds for the season. Damaging winds would likely be
the most probable concern as storms potentially cluster and spread
south-southeastward.
...Nebraska/eastern South Dakota/western Iowa...
A somewhat separate area of potential severe-storm development is
expected from parts of central Nebraska into southeast South Dakota.
Initiation is expected near a weak surface trough as temperatures
warm to near/above 100 F as CINH erodes. MLCAPE of near/above 1500
J/kg and effective shear of 30-40 kt will favor development of a few
organized cells and/or clusters. Severe gusts of 60-80 mph appear to
be the most likely hazard within the hot/well-mixed environment.
Isolated hail may also occur with any supercell, even with rather
warm temperatures aloft.
...Mid-Atlantic into the Carolinas/Georgia/north Florida...
A seasonably deep upper trough will persist across much of the
eastern CONUS today. A modest increase in northwesterly mid-level
winds are expected from the Mid-Atlantic into the Carolinas, Georgia
and northern Florida.
Relatively cool conditions, weak lapse rates, and the potential
influence of smoke will temper destabilization across the Mid
Atlantic. However, MLCAPE increasing to near 1000 J/kg amid 25-35 kt
of effective shear may support occasional storm organization, with a
primary threat of locally damaging winds.
Stronger heating/destabilization is expected farther south across
the Carolinas into Georgia and Florida. Deep-layer flow/shear will
be somewhat weaker compared to areas farther north, but may still be
sufficient for transient storm organization and a localized
damaging-wind threat.
...Southern Montana/northern Wyoming/Black Hills...
High-based convection is expected to develop this afternoon along
the northern periphery of the upper ridge, with the greatest storm
coverage expected across parts of northern Wyoming and southern
Montana. Overall buoyancy is expected to remain weak, but inverted-v
profiles will support a threat of strong to localized severe gusts
as storms spread eastward toward the Black Hills before weakening
into mid/late evening.
..Guyer/Wendt.. 07/26/2026
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