SPC Aug 4, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Mon Aug 03 2026

Valid 040100Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN AND NORTHERN MINNESOTA...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this evening over parts of western and northern Minnesota.
Severe wind gusts are also expected in parts of southeastern
Arizona.

...Western and Northern Minnesota...
On water vapor imagery, west-southwesterly mid-level flow is present
over much of the north-central U.S., with a subtle shortwave trough
evident over northern Minnesota. At the surface, a cold front is
located over northwestern Minnesota. Surface dewpoints ahead of the
front range from 65 to 70 F, and the RAP has MLCAPE in the 1500 to
2500 J/kg range. This is supporting scattered thunderstorm
development across northwest Minnesota. In addition, a 60 to 70 knot
mid-level jet is moving over the top of this moist and unstable
airmass, and is creating moderate deep-layer shear. This will be
favorable for organized storms capable of producing severe wind
gusts and isolated large hail. The severe threat will be maximized
with supercells that develop.

...Central High Plains...
The latest surface analysis shows a cold front located from
northeast Colorado northeastward into central Nebraska, along which
low-level convergence is maximized. This is supporting scattered
thunderstorm development. Just ahead of the front, an axis of
moderate instability is analyzed by the RAP over central and
southwest Nebraska, where MLCAPE is estimated to be from 1000 to
2000 J/kg. In addition, low to mid-level lapse rates are steep
according to the RAP, with 0-3 km lapse rates exceeding 8 C/km over
parts of southwest Nebraska. This environment will contribute to
strong downdrafts capable of producing isolated severe gusts.

...Southeast Arizona...
A moderately unstable airmass is currently located across southeast
Arizona, where the RAP has MLCAPE in the 1000 to 2000 J/kg range.
Thunderstorms are ongoing along the northern edge of the stronger
instability. These storms will move west-southwestward across the
remainder of southeastern Arizona over the next few hours. Steep low
to mid-level lapse rates will contribute to a potential for severe
wind gusts.

..Broyles.. 08/04/2026


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SPC Aug 3, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Mon Aug 03 2026

Valid 032000Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS INTO THE UPPER MIDWEST...AND SOUTHERN ARIZONA...

...SUMMARY...
Scattered severe thunderstorms are possible today into tonight
across parts of the eastern Dakotas into northern Minnesota, as well
as across portions of southern Arizona.

...20Z Update...
The MRGL Risk in the Northeast was trimmed behind an eastward-moving
band of frontal convection. This activity will continue to pose a
risk of damaging wind gusts and possibly a brief tornado this
afternoon, before moving into an increasingly stable air mass
sampled by the CAR 18Z sounding and/or moving off the southern New
England Coast.

Farther west, the latest surface analysis depicts a surface low at
the intersection of a cold front and lee trough in far northeast CO.
Current thinking is that high-based thunderstorms will develop in
the vicinity of this feature and spread east/northeastward into a
deeply mixed boundary layer in southwestern NE this evening -- where
a robust warm layer is present at the base of the EML (per LBF 18Z
sounding). There is some potential that this environment supports a
localized corridor of enhanced severe wind gusts (some upwards of 75
mph). However, the aforementioned capping and spatially limited
corridor casts uncertainty on the overall risk -- precluding an
upgrade at this time.

Elsewhere, the forecast remains on track and no changes were made
with this update.

..Weinman.. 08/03/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Aug 03 2026/

...Northern/Central Plains into the Upper Midwest...
Post-frontal thunderstorms occurring this morning across ND have
remained mostly sub-severe over the past couple of hours. A stout
low-level inversion noted on the observed 12Z INL sounding will
likely inhibit surface-based thunderstorms from developing until
late this afternoon or early evening across the eastern Dakotas into
northern MN. Still, gradual airmass destabilization is anticipated
across this region along/ahead of a cold front through the
afternoon. Large-scale ascent attendant to an ejecting mid-level
shortwave trough from MT into ND will eventually aid scattered
convective development along/near the front, most likely by 22-01Z.
Moderate instability coupled with strong deep-layer shear will
support some threat for supercells and large hail initially, before
upscale growth into clusters supports an increasing severe/damaging
wind threat with eastward extent into northern MN this evening. A
tornado or two may also occur as low-level shear gradually increases
in a narrow corridor ahead of the front this evening.

Isolated to widely scattered thunderstorm development is forecast
with southward extent into the central High Plains. A hot and very
well-mixed low-level airmass ahead of the front/surface trough
across this area may support occasional severe gusts with convective
outflow. But, weaker mid-level winds and related modest deep-layer
shear should result in only loosely organized clusters/cells. This
activity should weaken with the loss of daytime heating.

...Southwest...
Around 15-25 kt of east-northeasterly mid-level winds will persist
today across far southern AZ/NM, to the south of prominent upper
ridging that will remain anchored over the Southwest. Recent visible
satellite imagery shows mostly clear conditions across southeast AZ,
with latest surface observations showing ample low-level moisture
present (surface dewpoints generally in the low to mid 60s across
lower elevations). Ample heating of this moist airmass will support
moderate instability by mid afternoon. Current expectations are for
thunderstorms to initially develop over the higher terrain of
southeast AZ as convective temperatures are reached, and
subsequently spread west-southwestward into the lower deserts
through the evening. Some organization/clustering appears possible
with this activity, and the Slight Risk for severe wind gusts up to
60-75 mph has been maintained with no changes. Isolated hail may
also occur with the strongest cores that develop initially.

...Northeast/Northern Mid-Atlantic...
An upper trough with enhanced mid-level south-southwesterly flow
will advance eastward across the Northeast and northern Mid-Atlantic
today. A weak surface low should develop northward into southern
Quebec, with a trailing cold front advancing eastward across the
Northeast this afternoon/evening. Filtered daytime heating of a
seasonably very moist airmass (reference 12Z observed soundings from
OKX/ALB/GYX) will support modest MLCAPE up to 500 J/kg, even though
mid-level lapse rates remain quite poor. Thunderstorms developing
along and ahead of the cold front may pose an isolated threat for
damaging winds given the enhanced flow present at low/mid levels. A
brief tornado or two could also occur across parts of New England
where effective SRH may be locally greater in tandem with a
southerly low-level jet. Still, the overall poor thermodynamic
environment should limit a greater severe wind threat from
developing this afternoon.


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SPC Aug 3, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0726 AM CDT Mon Aug 03 2026

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
UPPER MIDWEST AND SOUTHEAST ARIZONA...

...SUMMARY...
Scattered severe thunderstorms are possible today across parts of
northern Minnesota into adjacent portions of the eastern Dakotas, as
well as across southeastern Arizona.

...Upper Midwest southward into the central High Plains...
Radar mosaic shows a loose cluster of mainly occasionally strong
thunderstorm activity over the Red River Valley. This activity has
developed partly in response to isentropic lift downstream of an
eastward-migrating mid-level speed max over the northern Rockies and
adjacent plains. The morning showers/thunderstorms will likely
reinforce a frontal zone draped southwest to northeast over the
region.

Heating in wake of early day cloud cover will foster moderate
destabilization by mid afternoon as mid to upper-level flow
gradually strengthens. The initial storms later today will likely
pose a risk for severe gusts and large hail and perhaps a tornado if
a couple of storms can acquire supercell characteristics and mature
within a moist axis ahead of the front. Otherwise, small clusters
will probably evolve with time and pose mainly a wind/hail threat.
Farther south, lower storm coverage is expected along a surface
trough into the central High Plains. Isolated, high-based storms
will slowly move east within a hot airmass featuring very steep
lapse rates. Isolated severe gusts may accompany the stronger cores
and outflow before these storms wane by mid evening.

...Southeastern Arizona/adjacent New Mexico...
Model guidance continues to indicate a belt of enhanced mid to upper
northeasterlies over northern Sonora into far southeastern
AZ/southwestern NM. Very strong heating resulting in moderate
destabilization and orographic lift will favor scattered
thunderstorm development by late afternoon into the early evening.
Models (e.g., MPAS, HREF) show a cluster or two propagating on
outflow into the lower deserts during the evening with very steep
0-3 km lapse rates preceding this convection. Severe gusts 60 to 75
mph will be the primary hazard.

...Northern Mid Atlantic through western New England...
Along and ahead of a weak cold front, trailing a deepening surface
low migrating northeastward toward the lower St. Lawrence Valley,
boundary-layer destabilization will probably be slowed, if not
inhibited, by weak mid-level lapse rates and early day cloud
cover/precipitation. However, strengthening deep-layer wind fields
and shear will potentially become more supportive of organized
thunderstorm development. If a couple of stronger updrafts can
develop, a risk for damaging wind gusts and perhaps a brief tornado
may materialize---contingent on sufficient destabilization occurring
prior.

..Smith/Bentley.. 08/03/2026


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SPC Aug 3, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Mon Aug 03 2026

Valid 031200Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON AND EVENING ACROSS PARTS OF NORTHERN MINNESOTA INTO
ADJACENT PORTIONS OF THE EASTERN DAKOTAS...

...SUMMARY...
Strong to severe thunderstorm development appears possible today
across parts of northern Minnesota into adjacent portions of the
eastern Dakotas, as well as across the eastern Arizona international
border vicinity and parts of the northern Mid Atlantic through
western New England.

...Discussion...
A compact, but fairly deep, lower/mid-tropospheric cyclone over the
Canadian Prairies is forecast to migrate across northern Manitoba
into western Hudson Bay today through tonight. One initial trailing
cold front is already advancing into the northern Great Plains, with
a more substantive cold front approaching the international border
and forecast to overtake it by mid afternoon, roughly across the
northwestern Minnesota through southeastern North Dakota, central
South Dakota, and western Nebraska vicinity.

As a notable upstream mid-level short wave trough accelerates across
the northern U.S. Rockies, toward northwestern Ontario, it appears
that a secondary surface low emerging from Wyoming will weaken while
migrating northeast of the Black Hills through the adjacent middle
Missouri Valley early today. Another surface low may form along the
front across northern Minnesota into northwestern Ontario this
evening, but it appears that the most rapid deepening will occur
north of Lake Superior overnight.

To the south and southwest of the mid-level wave, models indicate
that mid-level ridging will build across the Southwest during the
day, with highest heights becoming centered along an axis across
southwestern through central Arizona into north central New Mexico
by late afternoon.

Within the downstream westerlies, a notable mid-level trough is
forecast to pivot east and northeast of the lower Great Lakes
through New England. As it does, a remnant perturbation digging
toward the southern Appalachians may evolve into a weak mid-level
low across the Southeast, cut off from the westerlies.

...Northern Great Plains into Upper Midwest...
The influence of possible early period convection and associated
cloud cover on destabilization and convective potential later today
across parts of the central and eastern Dakotas into Minnesota
remains a bit unclear. However, by mid to late afternoon, guidance
generally indicates that a fairly sharp quasi-stationary
near-surface baroclinic zone will evolve across northwestern
Minnesota through southeastern North Dakota. It appears that this
may become a focus for at least a narrow corridor of modest
boundary-layer destabilization, coincident with strengthening south
to southwesterly lower/mid-tropospheric wind fields (including
30-40+ kt around 850 mb and 50-70 kt around 500 mb). This may
provide a window of opportunity for strong to severe storm
development, including a couple of supercells, by this evening,
before the front overtakes the instability axis with the passage of
the frontal wave.

...Southeastern Arizona/adjacent New Mexico...
Low-level moisture appears likely to remain relatively modest across
central and southern Arizona, with strong daytime heating and mixing
lowering surface dew points through the mid to lower 50s F by late
afternoon. However, along the southern periphery of the stronger
mid-level ridging, it appears that this may support at least
moderate boundary layer CAPE near the international border vicinity,
beneath 25+ kt east-northeasterly mid-level steering flow.

The higher terrain either side of the southern Arizona/New Mexico
state border will provide potential for a more substantive
clustering of convection, which may propagate across and south of
the international border by early this evening. If preceding
thunderstorm development, initially developing in the unstable
environment near the international border, does not generate too
much stabilizing outflow, it is possible that this could become
supportive of a swath of strong to severe wind gusts, aided by
evaporative cooling in a deeply mixed sub-cloud layer with 40-50 F
temperature/dew point spreads.

...Northern Mid Atlantic through western New England...
Along and ahead of a weak cold front, trailing a deepening surface
low migrating northeastward toward the lower St. Lawrence Valley,
boundary-layer destabilization will probably be slowed, if not
inhibited, by weak mid-level lapse rates and early day cloud
cover/precipitation, However, strengthening deep-layer wind fields
and shear will potentially become more supportive of organized
thunderstorm development with a risk for damaging wind gusts and
perhaps a tornado or two, if pre-frontal breaks in cloud cover can
allow for sufficient destabilization with daytime heating.

..Kerr/Supinie.. 08/03/2026


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