SPC AC 260559
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Sun Jul 26 2026
Valid 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
UPPER MIDWEST AND GREAT LAKES SOUTHWESTWARD INTO NEBRASKA...
...SUMMARY...
Severe thunderstorms capable of large to very large hail, damaging
winds (possibly 75+ mph), and potentially some tornado risk are
possible from the upper Mississippi Valley and Great Lakes
southwestward into portions of Nebraska, mainly this afternoon into
tonight.
...Parts of the Upper Midwest/Great Lakes...
An upper ridge will remain anchored from the Southwest into the
central Rockies and High Plains through the period. 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. This will result in a conditionally
favorable environment across a broad region, though with generally
subtle forcing mechanisms, considerable uncertainty remains
regarding storm evolution through the period.
Aside from any MCV influence on early-day convection, the most
likely initiation zone for diurnal storm development currently
appears to be from northern MN into WI, where one or more
low-amplitude midlevel vorticity maxima may impinge upon the
destabilizing environment. Initial supercell development would be
possible in this area, posing a threat of large to very large hail,
localized severe gusts, and potentially some tornado risk. Upscale
growth into one or more intense southeastward-moving clusters with
attendant severe-wind swaths would then be possible with time.
However, some guidance remains relatively sparse with
afternoon/evening development, resulting in uncertainty regarding
coverage and favored corridors of potentially significant severe
potential. Greater probabilities and an upgrade to Level-3/Enhanced
Risk may eventually be needed, depending on how the uncertainties
are resolved later today.
...NE into adjacent parts of southeast SD and western IA...
A somewhat separate area of potential severe-storm development is
expected from parts of central NE into southeast SD. Initiation is
expected near a weak surface trough as temperatures warm to near
above 100 F and CINH is removed. 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, despite rather warm
temperatures aloft.
...Mid-Atlantic into the Carolinas/GA/north FL...
A seasonably deep upper trough will persist across much of the
eastern CONUS today. A modest increase in midlevel northwesterly
flow is expected with time from the Mid-Atlantic into the Carolinas,
GA, and north FL.
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 wind.
Farther south, stronger heating/destabilization is expected across
the Carolinas into GA/FL. 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 MT/northern WY into the Black Hills...
High-based convection is expected to develop this afternoon along
the northern periphery of the upper ridge, with the greatest
relative coverage expected across parts of northern WY and southern
MT. Buoyancy is expected to remain weak, but inverted-v profiles
will support a threat of strong to localized severe gusts as storms
move eastward towards the Black Hills before weakening this evening.
..Dean/Squitieri.. 07/26/2026
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
SPC AC 260540
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sun Jul 26 2026
Valid 271200Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
LAKES INTO PARTS OF THE OHIO VALLEY...
...SUMMARY...
Severe storms capable of mainly damaging winds and large hail are
possible across the Great Lakes into the Ohio Valley Monday into
Monday night. More sporadic occurrences of damaging wind appear
possible in the Mid-Atlantic, Tennessee Valley, central High Plains,
and southeast Arizona.
...Synopsis...
Within the northeast periphery of an upper high centered over the
southern High Plains, a low-amplitude short-wave trough and
associated mid-level jet streak will move through the Great Lakes.
At the surface, an area of low pressure over WI Monday morning is
forecast to develop either south or southeast along a cold front
advancing south through the Great Lakes. The western extension of
that boundary is expected to stall over the mid MO Valley into
central High Plains.
...Great Lakes into the Tennessee Valley and central Appalachians...
Latest model data indicate the potential for multiple storm clusters
to be ongoing at 12Z Monday from northern MN into the Midwest within
a broad zone of warm advection and moisture transport centered
around 850 mb. The duration and extent of any early-day storms will
have implications on the subsequent air mass destabilization later
in the day ahead of the synoptic cold front. Where stronger heating
can occur, the presence of boundary-layer dewpoints in the 60s to
low/mid 70s beneath the eastern edge of an EML plume will yield
MLCAPE as high as 2500-3500+ J/kg.
As alluded to above, there is considerable model spread in location
of storm initiation and subsequent evolution Monday afternoon into
night. That being said, storm development appears most probable
along the cold front in WI and lower MI Monday afternoon or evening
within a zone of strengthening forcing for ascent preceding the
short-wave trough. The presence of 40-50+ kt effective bulk shear
magnitudes will support organized storm modes, including supercells
initially with an associated large hail threat. The extent of any
tornado threat will be dependent on semi-discrete supercells being
maintained within a zone of stronger low-level shear from southeast
WI and southern lower MI into northern IL and IN, and perhaps
western OH Monday afternoon and evening.
Damaging-wind potential is expected to increase Monday evening into
night as storms coalesce into one or multiple cold-pool-driven MCSs.
The preferred corridor for that occurrence still appears to be from
lower MI into IN and OH, and perhaps KY, where an upgrade to a
level-3/Enhanced Risk may become necessary in later outlooks. Storm
clusters capable of damaging winds could reach as far south and east
as the TN Valley through Cumberland Plateau and Allegheny Mountains
Monday night, owing to modestly strong north/northwest steering
winds.
...Mid-Atlantic...
A southeastward extension of stronger, mid/upper-level winds is
forecast to overspread the region Monday afternoon into night with
effective bulk shear approaching 30 kt in some areas during the peak
of the diurnal heating cycle. Scattered storms appear possible along
a lee trough Monday afternoon within a moist and moderately unstable
air mass with MLCAPE up to 1000-2000 J/kg. Steepening low-level
lapse rates will enhance damaging wind potential, especially in
areas of stronger shear where some cold-pool organization is
possible.
...Central High Plains...
Aided by a weak mid-level disturbance rotating around the upper
high, widely scattered thunderstorms appear possible within a moist
and moderately unstable upslope regime Monday afternoon into
evening. Forecast soundings indicate a well-mixed boundary layer
with sizable temperature-dewpoint spreads, suggesting the potential
for a few severe wind gusts with the strongest storms.
...Southeast Arizona...
Model soundings indicate some enhancement of easterly mid-level flow
across the region Monday with effective bulk shear magnitudes up to
35 kt. The models indicate afternoon storm initiation along the
higher terrain closer to the international border within a
relatively deep and well-mixed boundary layer. Some cold-pool
organization appears possible given the stronger vertical shear with
an associated risk of severe wind gusts.
..Mead.. 07/26/2026
WUUS02 PTSDY2
SPC AC 260726
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Sun Jul 26 2026
Valid 281200Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
MID-ATLANTIC INTO THE CAROLINAS AND CENTRAL AND SOUTHERN
APPALACHIANS...
...SUMMARY...
Severe thunderstorms capable of mainly damaging winds appear
possible from the southern Mid-Atlantic into the Carolinas and
central and southern Appalachians Tuesday into Tuesday evening.
Isolated severe wind gusts may occur in the central High Plains.
...Synopsis...
A short-wave trough initially over the lower Great Lakes Tuesday
morning is forecast to evolve into a closed low over the
Mid-Atlantic. Within the base of that feature, a belt of enhanced
mid-level flow will spread from the OH Valley into VA and NC by
afternoon. At the surface, an area of low pressure over southwest
ON Tuesday morning is expected to reform in the Delmarva by
afternoon with a lee trough extending southwest along the Piedmont.
Meanwhile, a cold front will advance southeast through the central
and southern Appalachians, the southern Mid-Atlantic into the
Carolinas.
...Mid-Atlantic into Southern Appalachians...
Showers and thunderstorms (some potentially strong) are expected to
be ongoing Tuesday morning from the upper OH Valley into the
Mid-Atlantic and central Appalachians within a zone of forcing for
ascent preceding the short-wave trough. Various 00Z model data
indicate deep convection lingering into afternoon from the central
Appalachians into the Delmarva and points north, leading to
uncertainty in the degree of air mass destabilization in those
areas. Where stronger heating can occur, the presence of a moist air
mass will contribute to moderate instability by afternoon within a
kinematic environment featuring anywhere from 30 to 45 kt of
deep-layer shear.
Thunderstorms are expected to increase in coverage and intensity
during the afternoon preferentially along the cold front and lee
trough where sufficient destabilization has occurred. Organized
storm modes appear possible, including supercells and bowing
structures, with the primary hazards being damaging wind gusts. Some
tornado threat could materialize Tuesday afternoon in the Delmarva
near the surface low. That threat is conditional on sufficient air
mass destabilization and the presence of a supercell mode.
...Northern and Central High Plains...
Between a deepening lee trough over the northern High Plains and a
stalled surface front along the KS-OK border, a zone of moist and
moderately unstable upslope flow is forecast. Thunderstorms are
expected to develop during the afternoon and evening along favored
terrain with 30-35 kt of deep-layer shear supporting some level of
organization. Severe wind gusts appear to be the primary hazard with
the strongest storms.
..Mead.. 07/26/2026
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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