Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1256 AM CDT Sat Jul 25 2026

Valid 251200Z - 261200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
CENTRAL MT...AND ALSO ACROSS PARTS OF SD...

...SUMMARY...
Storms with scattered severe wind gusts are possible across parts of
Montana and South Dakota this afternoon and evening.

...MT into SD and vicinity...
An expansive upper ridge will remain anchored over much of the
southwest and central CONUS through the period. Very hot
temperatures are expected this afternoon from MT into the Dakotas.
Isolated to scattered storms within the hot and well-mixed
environment will result in a broad area of at least isolated
severe-wind potential. 5% wind probabilities have been expanded to
cover this potential, with 15% wind probabilities (equivalent to
categorical Level 2/Slight Risk) added across parts of MT and SD,
where terrain features may enhance storm coverage within the
favorable severe-wind environment. 

For parts of western/central MT, convection that develops by
early/mid afternoon near the high terrain is expected to spread
eastward into the hot and well-mixed environment. This convection
may be aided by a low-amplitude midlevel vorticity maximum moving
around the periphery of the upper ridge. Increasing storm coverage
and gradually strengthening mid/upper-level flow may allow for one
or more outflow-driven clusters to develop and spread
east-northeastward into early evening, with a threat of severe
gusts. Localized gusts of 75+ mph cannot be ruled out, especially if
deeper convection is able to spread into areas where very deep
mixing and heating to near/above 100 F occurs prior to storm
arrival. 

Farther east, very strong heating is expected across parts of
western/central SD, with temperatures in some areas potentially
rising to near/above 105 F. Low-level moisture will be relatively
sparse, but MLCAPE of near/above 1000 J/kg will be possible where
50s F dewpoints can be maintained within the well-mixed environment.
Initial storm development near the Black Hills will quickly become
outflow dominant as it spreads eastward, with an increasing threat
of severe gusts. Deep-layer shear will be somewhat favorable for
organized convection, and some guidance depicts development of a
persistent cluster or loosely organized MCS that moves eastward
across SD along a weak surface boundary. Should this occur, a
corridor of more organized severe-wind threat (with gusts
potentially near/above 75 mph) will be possible. 

...Northern/eastern MN into WI and Upper MI...
Conditional severe potential remains evident across parts of the
Upper Midwest, though confidence regarding storm coverage and timing
remains very low within the weakly forced environment. Moderate to
strong destabilization is possible along/south of a surface front
that is forecast to extend from northeast ND into northern MN/WI by
late afternoon. Effective shear of 50+ kt will be more than
sufficient for storm organization, but most guidance remains rather
muted regarding potential for diurnal storm development. If storms
are able to develop during the afternoon or evening, then a threat
for hail, damaging wind, and possibly a tornado could evolve. Even
if diurnal storm development is limited, vigorous elevated storms
may evolve within a warm-advection regime near/north of the front
late tonight, which would pose a threat for hail and perhaps locally
damaging wind. Confidence remains too low to include more than
Level-1/Marginal Risk equivalent probabilities at this time. 

...Northeast NV/northern UT into eastern ID...
Storm development is expected during the afternoon across parts of
northeast NV, along the western periphery of the upper ridge. These
storms will spread into adjacent parts of southeast ID and northwest
UT with time. Strong to locally severe gusts will be possible with
these storms as they move northeastward through a well-mixed
environment.  

...South-central/southeast AZ...
High-based convection is again expected across southeast AZ during
the afternoon, with initial downburst potential. Modest enhancement
to easterly flow along the southern periphery of the upper ridge may
allow for localized strong to severe gusts to spread westward into
parts of south-central AZ, before convection weakens later Saturday
night.

..Dean/Squitieri.. 07/25/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1224 AM CDT Sat Jul 25 2026

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
MISSISSIPPI VALLEY INTO UPPER MIDWEST...

...SUMMARY...
Severe thunderstorms capable of mainly large hail and damaging winds
are possible from the upper Mississippi Valley and Great Lakes into
portions of the mid Missouri Valley on Sunday and Sunday night.

...Synopsis...

A dominant upper high will remain anchored over the central and
southern Plains with an associated ridge extending north into
central Canada. Within the periphery of the ridge, a belt of
enhanced mid-level flow will extend from the Pacific Northwest
through south-central Canada into the Great Lakes and middle OH
Valley. A series of weak mid-level disturbances will translate
through the stream of higher-momentum flow, the most notable of
which is a short-wave trough that will crest the ridge axis over
SK/MB. Modest height falls are expected downstream from that feature
from northern MN into the upper Great Lakes Sunday night/early
Monday.

At the surface, a cool front attending the SK/MB system will advance
through the northern High Plains into the ND-MN Red River Valley. A
weak front will settle south through northern parts of MN and WI
before stalling, while a separate frontal system extends from the
Southeast into the Midwest with another boundary.


...Upper Mississippi Valley and Great Lakes into the Mid Missouri
and Ohio Valleys...
Capping associated with the mid-level ridge and the subtle nature of
mechanisms to sustain forcing for ascent lead to considerable
uncertainty in the location, areal coverage, and intensity of
thunderstorms Sunday into Sunday night. That being said, a few
early-day thunderstorms appear possible across the upper Midwest
within a zone of warm advection and aided by the glancing influence
of a weak disturbance moving through the upper Great Lakes. The
storms would likely be elevated within a plume of moderate
instability and ample vertical shear, suggesting some potential for
large hail and damaging winds.

By afternoon, a reservoir of moderate to strong instability is
forecast across the Midwest with the various models indicating the
potential for diurnally enhanced thunderstorm development at various
locations from the mid MO Valley into lower MI. Confidence in any
one scenario remains low, and as such, a modest expansion of the
level 1/Marginal Risk was made across parts of the OH Valley to
account for the broad range of potential outcomes. Given the degree
of instability and seasonably strong vertical shear, higher severe
weather probabilities and related conditional intensity groups may
become necessary once forecast details become more clear. 

As alluded to in the synopsis, stronger forcing for ascent tied to
the approaching Canadian disturbance and surface front may support a
more focused area of thunderstorm development over MN Sunday night.
Subsequent upscale growth into a forward-propagating MCS appears
possible, which would increase the potential for a swath of severe
wind gusts.  


...Southeast...
One or multiple weak disturbances aloft are expected to overspread
the region, along with a slight increase in mid/upper-level winds.
In response, a weak surface low may develop across upstate SC, along
a subtle front/confluence zone in the area. Thunderstorms are
expected to increase in coverage and intensity through the afternoon
along the front and developing sea-breeze boundaries within a very
moist and moderately unstable air mass. Steep low-level lapses and
high precipitable water content will enhance downdraft potential
with an associated risk for locally damaging winds.

..Mead.. 07/25/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0219 AM CDT Sat Jul 25 2026

Valid 271200Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE GREAT
LAKES INTO PARTS OF THE OHIO VALLEY...

...SUMMARY...
Severe storms capable of damaging winds and large hail are possible
across the Great Lakes into the Ohio Valley Monday into Monday
night.

...Synopsis...
A potent short-wave trough and associated 50+ kt mid-level jet will
move through the Great Lakes within the northeast periphery of an
upper high centered over the southern High Plains. That upper-air
system will be attended by a deepening surface low that is forecast
to develop from the MN Arrowhead through the U.P. and northern Lower
MI into southwest ON during the forecast period. Meanwhile, a
trailing cold front will advance through the upper Midwest and Great
Lakes into the OH Valley.


...Great Lakes and Ohio Valley...
Clusters of thunderstorms may be ongoing Monday morning across parts
of the Midwest and upper Great Lakes within a broad zone of
low-level warm advection and increasing forcing/DCVA downstream from
the mid-level trough. A fairly large area of moderate instability
and seasonably strong vertical shear is forecast at the outset of
the forecast period, and as such, the most intense storms will be
capable of large hail and damaging winds. A subset of the early-day
storms may evolve into one or multiple MCSs by afternoon ahead of
the surface low and cold front, leading to a corridor of more
focused damaging wind potential from Lower MI into IN and OH, and
possibly parts of KY and WV Monday night.

Despite the presence of strong instability along the front from the
mid MS Valley into mid/lower MO Valley, stronger capping and weaker
forcing for ascent are expected to lower the chance of thunderstorm
development.


...Central High Plains...
Thunderstorms are expected to develop Monday afternoon into evening
within a moderately unstable, post-frontal upslope flow regime.
Generally weak vertical shear is expected to limit storm
organization; however, the presence of steep low/mid-level lapse
rates and potentially large temperature-dewpoint spreads suggests a
threat for isolated severe wind gusts.

..Mead.. 07/25/2026