SPC Jun 29, 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
0755 PM CDT Sun Jun 28 2026

Valid 290100Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Severe thunderstorms are possible tonight across the Dakotas. Large
to very large hail and severe winds are the primary hazards. More
isolated severe storms capable of large will be possible in northern
Wisconsin late tonight into early tomorrow morning.

...Discussion...
Water vapor imagery this evening shows a mid-level trough located
across northern Montana into Alberta/Saskatchewan. At the surface, a
low is occluding to the north across southern Alberta, with a
secondary low developing across eastern Colorado. A surface cold
front extends across portions of the western Dakotas north to the
occluding front in Canada. As the surface low in Colorado deepens
and moves northeastward late this evening, thunderstorm activity is
expected to increase in coverage near the low/cold front and along a
warm front lifting into the Upper Midwest.

...Northern Plains...
Initial thunderstorm development has occurred this evening within a
zone of weak low-level convergence in central/western North Dakota
as enhanced mid-level westerly flow overspreads the region from the
trough to the west. Daytime heating and dew points in the upper 60s
F have led to strong buoyancy across the region. Low-level flow is
rather weak but deep layer shear around 50-55 kts will likely
support a few isolated supercells capable of large to very large
hail. See MCD#1369 for more information.

Additional thunderstorm activity is progged to develop overnight as
the surface low moves northward and forcing for ascent continues to
increase. Aforementioned strong instability and deep layer shear
profiles will support supercells capable of large to very large
hail. The Slight Risk was maintained with this update to account for
this potential overnight. See MCD#1370 for more information.

...Upper Midwest...
Thunderstorm development is expected along and north of a warm front
lifting into northern Wisconsin late tonight into early Monday
morning. As the warm front lifts northward, moisture and instability
will increase from the south. Moderate to strong instability
overlapping increasing deep layer shear from the trough to the west
will support a mix of supercells and multi-cell clusters with
potential for large hail. A Marginal Risk was maintained across
central/northern Wisconsin and extended into the northern Lower
Michigan Peninsula to account for this potential.

...West Texas...
A few stronger storms may continue across portions of western Texas
near dryline and south to the Trans Pecos with a few instances of
marginally severe hail and gusty winds. Loss of daytime heating
should limit the duration of this risk past sunset with storms
decreasing in coverage and intensity.

..Thornton.. 06/29/2026


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SPC Jun 28, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1131 AM CDT Sun Jun 28 2026

Valid 281630Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN PLAINS...CAROLINAS...AND A PART OF THE MIDWEST...

...SUMMARY...
Severe thunderstorms are expected mainly tonight across the Dakotas.
Large to very large hail and severe winds are the primary hazards.
Thunderstorms capable of scattered wind damage are possible in parts
of the Carolinas.

...Dakotas/northern Plains...
A belt of south-southwesterly mid-level flow near 50 kt will be
maintained from Colorado to the Dakotas, east of the broad closed
low over the northern Great Basin/Rockies. A separate lee cyclone
is expected to form in the vicinity of northeast Colorado this
afternoon and then progress northeastward across Nebraska/South
Dakota overnight.

A few storms will be possible in North Dakota during the afternoon
with perhaps an isolated severe risk developing, but the primary
regional severe risk is expected tonight. Much of the severe threat
will likely focus after dark immediately north of the lee cyclone
into South Dakota as low-level moisture steadily spreads
west-northwestward. This increasing moisture and forcing for ascent
preceding the surface cyclone (and subtle embedded speed maxima
aloft) will likely support thunderstorm development overnight across
western South Dakota into southern North Dakota. The environment
will favor supercells, which will tend to be elevated, and small
thunderstorm clusters capable of large to very large hail and severe
wind gusts.

...Upper Mississippi Valley...
A bowing cluster has weakened and tended to grow downscale this
morning but otherwise persists across eastern Iowa at midday. Some
redevelopment/re-intensification could occur on the cluster's
southern periphery near a warm front. However, this is highly
uncertain given the increasing mid-level capping/EML advection the
remainder of the night.

Later tonight, a zone of low-level warm advection will be focused
across Wisconsin along the northeast edge of the warm elevated mixed
layer. Sufficient moistening above the surface and large CAPE will
favor the potential for at least isolated large hail/strong gusts
with mostly elevated storms tonight.

...Carolinas and far southern Virginia this afternoon/evening...
A convectively augmented mid-level disturbance over the southern
Appalachians will move southeastward into the Piedmont by this
afternoon. An airmass sampled by area 12 UTC raobs (PW near 2
inches) will heat/destabilize to the south of a patch of clouds that
are more prevalent over western North Carolina. Steepening low-level
lapse rates and a belt of slightly stronger westerly 3-6 km flow (30
kt) may act to loosely organize cold pools of developing
thunderstorm clusters. Isolated to scattered wind damage (50-60 mph
gusts) will be the primary hazard with the more intense water-loaded
thunderstorm cores until around sunset.

...West Texas late this afternoon/evening...
Strong surface heating and deep mixing along a sharpening dryline
will allow high-based thunderstorm development from late afternoon
through late evening. Flow aloft will be weak, but inverted-V
profiles will yield isolated severe outflow gusts of 60-75 mph.

..Guyer/Supinie.. 06/28/2026


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SPC Jun 28, 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
0744 AM CDT Sun Jun 28 2026

Valid 281300Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE DAKOTAS
AND PORTIONS OF MINNESOTA AND IOWA AND PARTS OF THE CAROLINAS...

...SUMMARY...
Severe thunderstorms are possible this morning over northern Iowa
and southern Minnesota, and mainly tonight across the Dakotas. Large
to very large hail and severe winds are the primary hazards.
Thunderstorms capable of scattered wind damage are possible in parts
of the Carolinas.

...Dakotas to IA/WI through tonight...
Radar mosaic this morning shows a bow echo moving eastward along the
MN/IA border primarily north of a buoyancy gradient/warm frontal
zone. Occasional severe gusts (60-70 mph) have been observed with
this MCS the past couple of hours. Expecting more of an
east-southeastward motion with the linear system with a continued
risk for wind damage before perhaps weakening near the MS River
towards midday/early afternoon.

Farther west, a belt of south-southwesterly midlevel flow near 50 kt
will be maintained from CO to the Dakotas, east of the broad closed
low over the northern Great Basin/Rockies. A separate lee cyclone
is expected to form in the vicinity of northeast CO this afternoon
and then progress northeastward across NE/SD overnight. In the wake
of the morning storms, richer low-level moisture will advect
northward in tandem with a warm front. Model guidance continues to
delay storm development for much of the day as an EML overspreads a
destabilizing airmass across the north-central US. A few storms
will be possible in ND during the afternoon with perhaps an isolated
severe risk developing.

Much of the severe threat will likely focus after dark immediately
north of the lee cyclone into SD. Westward advection of richer
moisture and ascent preceding the surface cyclone (and subtle
embedded speed maxima aloft) will likely support elevated
thunderstorm development overnight across western SD into southern
ND. The environment will favor elevated supercells and small
thunderstorm clusters capable of large to very large hail and severe
gusts.

Farther east, a zone of low-level warm advection will be focused
across WI by late evening/early tonight along the northeast edge of
the warm elevated mixed layer. Sufficient moistening above the
surface and large CAPE will favor the potential for at least
isolated large hail/strong gusts with largely elevated storms
tonight.

...Carolinas/southern VA this afternoon/evening...
A convectively augmented mid-level disturbance over the southern
Appalachians will move into the Piedmont by this afternoon. A moist
airmass sampled by area 12 UTC raobs (PW near 2 inches) will
heat/destabilize to the south of a patch of clouds more prevalent
over western NC. By early to mid afternoon, steepened 0-2 km lapse
rates and a belt of slightly stronger westerly 3-6 km flow (30 kt)
may act to loosely organize cold pools of developing thunderstorm
clusters. Isolated to scattered wind damage (50-60 mph gusts) will
be the primary hazard with the more intense water-loaded
thunderstorm cores.

...West TX late this afternoon/evening...
Strong surface heating and deep mixing along a sharpening dryline
will allow high-based thunderstorm development from late afternoon
through late evening. Flow aloft will be weak, but inverted-V
profiles will favor isolated severe outflow gusts of 60-75 mph.

..Smith/Jewell.. 06/28/2026


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SPC Jun 28, 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 Sun Jun 28 2026

Valid 281200Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE DAKOTAS
AND NORTHWEST MINNESOTA...AND ACROSS NORTHERN IOWA AND VICINITY...

...SUMMARY...
Severe thunderstorms are possible today across northern Iowa and
vicinity, and mainly tonight across the Dakotas. Large to very large
hail and severe winds are the primary hazards.

...Dakotas to IA/WI through tonight...
As the primary cyclone occludes near the southwest SK/southeast AB
border, a belt of south-southwesterly midlevel flow near 50 kt will
be maintained from CO to the Dakotas, east of the broad closed low
over the northern Great Basin/Rockies. A separate lee cyclone is
expected to form in the vicinity of northeast CO this afternoon and
then progress northeastward across NE/SD overnight. A storm cluster
will likely be ongoing near the southwest MN/northwest IA border at
the start of the period, as a continuation of the ongoing storms
along the NE/SD border. These morning storms will pose a threat for
occasional large hail/wind damage along the warm front/buoyancy
gradient through midday/early afternoon. In the wake of the morning
storms, a surface warm front demarcating boundary-layer dewpoints
into the 70s will likewise move northward slowly across IA into
southern MN/WI. West of the morning storms, a warm elevated mixed
layer observed in 00Z soundings across the central Plains will act
to cap the moistening boundary layer and likely inhibit additional
warm sector storm development through much of the period. A few
storms will be possible in ND during the afternoon, though storm
coverage/intensity are both in question given weak-moderate buoyancy
and limited forcing for ascent.

Much of the severe threat will likely be delayed until tonight
immediately north of the lee cyclone into SD. Westward advection of
richer moisture and ascent preceding the surface cyclone (and subtle
embedded speed maxima aloft) will likely support elevated
thunderstorm development overnight across western SD into southern
ND. The environment will favor elevated supercells capable of
producing very large hail (2-3 inches in diameter) and occasional
severe gusts.

Farther east, a zone of low-level warm advection will be focused
across WI by late evening/early tonight along the northeast edge of
the warm elevated mixed layer. Sufficient moistening above the
surface and large CAPE will favor the potential for at least
isolated large hail/strong gusts with largely elevated storms
tonight.

...Carolinas/southern VA this afternoon/evening...
An MCV now over KY will turn more southeastward today, downstream
from an amplifying ridge over the lower and middle MS Valley.
Destabilization and steepening of low-level lapse rates in cloud
breaks, along with ~25 kt midlevel flow, will support isolated wind
damage potential with storm clusters during the afternoon/evening.

...West TX late this afternoon/evening...
Strong surface heating and deep mixing along a sharpening dryline
will allow high-based thunderstorm development from late afternoon
through late evening. Flow aloft will be weak, but inverted-V
profiles will favor isolated severe outflow gusts of 60-75 mph.

..Thompson/Chalmers.. 06/28/2026


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