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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SPC Aug 3, 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
0752 PM CDT Sun Aug 02 2026

Valid 030100Z - 031200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING
INTO TONIGHT ACROSS PARTS OF THE NORTHERN MID ATLANTIC AND THE
NORTHERN GREAT PLAINS...

...SUMMARY...
The risk for severe weather appears generally low across much of the
U.S. through tonight.

...01Z Update...

...Southeastern Arizona...
Instability along the higher terrain of east central Arizona into
adjacent west central/southwest New Mexico has been sufficient to
support weak to modest thunderstorm development. Despite weak, but
favorably oriented, northeasterly steering flow, storms have been
unable to propagate away from the higher terrain due to minimal
destabilization in lower elevations. This is largely due to rather
modest boundary layer moisture, including surface dew points
lowering to around 50 F with continuing daytime heating and mixing.

...Northern Mid Atlantic...
Downstream of a consolidating mid-level impulse across the lower
Great Lakes region, destabilization remains sufficient to maintain
scattered thunderstorm development across parts of the Allegheny
Plateau/upper Ohio Valley into lower Great Lakes region. Aided by
high boundary-layer moisture content and momentum associated with
30+ kt southwesterly deep-layer mean flow, it appears that the risk
for localized damaging wind gusts could linger into the 03-05Z time
frame before diminishing.

As the mid-level perturbation and associated surface troughing
slowly shift eastward/northeastward, convection allowing output,
including HREF/REFS calibrated thunderstorm guidance, suggest that
intensifying thunderstorm development is possible late tonight in
the warm sector across parts of eastern Pennsylvania toward the
lower Hudson Valley. Based on forecast soundings, given the high
boundary-layer moisture content, it does not appear out of the
question that wind profiles could become marginally sufficient for
isolated transient supercell structures with a risk for damaging
wind gusts and/or perhaps a tornado.

...Eastern North Dakota into northwestern Minnesota...
Strengthening forcing for ascent, aided by lower/mid-tropospheric
warm advection, probably will support increasing potential for
thunderstorm development by late tonight. Based on forecast
soundings this will be generally elevated/high-based in nature, but
potential instability and cloud-bearing shear might be sufficient to
support some risk for small to marginally severe hail.

..Kerr.. 08/03/2026


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SPC Aug 2, 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
0249 PM CDT Sun Aug 02 2026

Valid 022000Z - 031200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE EAST
AS WELL AS PARTS OF THE SOUTHWEST AND NORTHERN PLAINS...

...SUMMARY...
Scattered strong to locally severe thunderstorm development is
expected this afternoon and evening across parts of the lower Great
Lakes and upper Ohio Valley into the middle and southern Atlantic
Piedmont. Damaging winds are the primary hazard, although a tornado
could occur.

...20Z Update...
Only minor changes were made with this update. The MRGL Risk was
expanded slightly eastward in portions of eastern SC, where an
ongoing cluster of thunderstorms will continue to pose a risk of
damaging wind gusts, given a very warm/moist downstream air mass.
Farther north, the MRGL Risk was expanded into parts of northern NJ
and northeast PA. Clouds breaks have supported modest
destabilization of a moist air mass, and high-resolution guidance
depicts thunderstorms moving into the area tonight -- focused along
a northward-moving warm front. Despite modest instability, enhanced
low-level flow/shear overspreading the region in tandem with the
warm front could support a couple loosely organized cells/clusters
with an accompanying risk of damaging wind gusts and perhaps a brief
tornado. Elsewhere, the forecast remains on track and no changes
were needed.

..Weinman.. 08/02/2026

.PREV DISCUSSION... /ISSUED 1116 AM CDT Sun Aug 02 2026/

...Eastern States...
Current satellite imagery shows a positively titled shortwave trough
extending from Lower MI southwestward into the Mid-South, while
recent surface analysis places a corridor of low pressure associated
with this shortwave from the Middle OH Valley into the Lower Great
Lakes. Several surface lows are embedded within this broader area of
low pressure, including a primary low over north-central OH/western
Lake Erie. A cold front extends southward from this low to the TN/NC
border vicinity before arcing back more southwestward through
central AL and southern MS.

This system (i.e. both the shortwave trough and associated cold
front) is forecast to gradually push eastward while weakening.
Airmass preceding this system is very moist, evidenced by upper
60s/low 70s dewpoints and PW values at or above 2 inches on the
regional 12Z soundings. Widespread cloud cover is in place, but
ample moisture has already resulted in airmass destabilization,
although the overall buoyancy will remain muted by poor lapse rates.
General expectation is for thunderstorm coverage to increase
substantially over the next few hours, fostered by a combination of
low-level confluence and modest large-scale ascent.

Low to mid-level flow throughout the eastern periphery of the
shortwave trough is generally expected to be modest, ranging from
around 40 kt across the Allegheny Plateau/upper Ohio Valley/lower
Great Lakes vicinity to 20 kt across GA and SC. Consequently, a few
more organized storms are possible across portions of the Allegheny
Plateau, upper Ohio Valley, and lower Great Lakes, while a largely
disorganized multicellular mode is anticipated elsewhere.
Water-loaded downbursts are the primary risk, although low-level
shear/SRH in the presence of a moist boundary layer suggests a brief
tornado is possible where greater storm organization is
expected.

...North Dakota/northwest Minnesota...
Expansive upper ridging exists from southern CA/western AZ through
the Plains and into Manitoba and Ontario. A strong shortwave trough
is forecast to progress through Canadian Prairie Provinces within
the northern periphery of this ridging. A cold front associated with
this wave is expected to push eastward across the Dakotas,
interacting with a moistening airmass across the region. A
conditional risk for severe thunderstorms exists this afternoon, but
most of the guidance keeps the airmass capped and free of deep
convection. Better potential for thunderstorm development is
expected overnight and into tomorrow morning as large-scale ascent
attendant to the approaching shortwave combines with warm-air
advection to foster elevated thunderstorm development. Isolated
instances of hail and a strong gust or two are possible with these
storms.

...Southeast Arizona/far southwest New Mexico...
Widely scattered thunderstorms should develop over the
mountains/higher terrain of the central/southern Arizona/New Mexico
border vicinity this afternoon. Moderate easterly/northeasterly
mid-level flow should favor southwestward motion into the lower
terrain of southeast Arizona. Modest buoyancy should allow for storm
persistence across southeast AZ, including the potential for
isolated strong to severe gusts.


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