SPC Jun 29, 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
0722 AM CDT Mon Jun 29 2026

Valid 291300Z - 301200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
SOUTH DAKOTA INTO NORTHWEST MINNESOTA...

...SUMMARY...
Severe thunderstorms capable of an intense swath of severe wind
gusts are likely across northeast South Dakota into northwest
Minnesota through midday. Later today, severe thunderstorms are
possible from parts of the northern Plains into the Upper Midwest.
Large hail and severe winds are the primary concerns, though a
couple of tornadoes may also occur.

...Dakotas/Mid-Missouri Valley/Upper Midwest...
Water-vapor imagery this morning shows a mid-level shortwave trough
over the central Rockies. This upper disturbance will acquire a
negative tilt and move into the central Dakotas by early evening. A
surface low over the north-central Plains will develop northward
into eastern ND by 00z as a warm front advances northward across
much of MN.

Through midday, an intense supercell over northeast SD will continue
to move quickly northeastward through parts of the eastern Dakotas
this morning and into northwest MN. Recent CAM model guidance
(i.e., time-lagged HRRR) has been remarkably consistent in showing
the evolution of the SD thunderstorm complex into northern MN today.
Have upgraded to an Enhanced Risk downstream of this extremely
intense supercell evolving into a bow within a focused mesoscale
corridor. Please refer to MCD #1376 for short-term forecast
details.

Later this afternoon, a very moist airmass will become very unstable
over parts of the Upper Midwest. Isolated to scattered
thunderstorms are forecast by late afternoon as large-scale ascent
associated with the approaching upper wave overspreads the region.
Ample deep-layer shear coupled with the large buoyancy will favor
supercells. Large to very large hail, a couple of tornadoes, and
severe gusts will be possible with this surface-based activity.
Towards the early evening, additional storms are likely to develop
farther east over MN with a hail/wind threat likely persisting
through the evening.

...Kansas/Oklahoma/Texas...
Isolated high-based thunderstorms are possible near the dryline.
Moderate instability is expected within this region with generally
weak deep layer shear. Strong evaporatively cooled downdrafts will
be capable of severe gusts with the more intense cores.

..Smith/Jewell.. 06/29/2026


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SPC Jun 29, 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
0100 AM CDT Mon Jun 29 2026

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
NORTHERN PLAINS AND UPPER MIDWEST...

...SUMMARY...
Severe thunderstorms are possible from parts of the northern Plains
into the Upper Midwest today. Large hail and severe winds are the
primary concerns, though a couple of tornadoes may also occur.

...Synopsis...
A shortwave trough will advance eastward from the northern Rockies
into the northern Plains today. At the surface, a low will move
northward out of Nebraska into the Dakotas, with a cold front/dry
line extending southward to a secondary low across the central
Plains. Thunderstorm activity is likely to be ongoing at the start
of the period near the northern surface low across portions of the
Dakotas. Additional thunderstorm activity is expected in the wake of
the morning convection near the warm front lifting across North
Dakota into Minnesota and near the cold front back into portions of
the Mid-Missouri Valley and central Plains.

...Dakotas/Mid-Missouri Valley/Upper Midwest...
Elevated supercell activity is likely to be ongoing at the start of
the period across portions of the Dakotas near the surface low and
nose of the low-level jet axis. The environment will be
characterized by moderate to strong instability and strong deep
layer shear. Guidance suggests that this will have the potential to
produce large to very large hail and damaging wind.

As the low develops, a warm front will extend into North
Dakota/Minnesota by the afternoon. Evolution of the morning activity
remains uncertain, but it appears that additional storms will
develop near the warm front and back near the low/cold front into
the afternoon. Near the warm front, filtered heating through broken
low to mid-level cloud cover will allow for moderate instability by
the afternoon. A plume of steep low to mid-level lapse rates will
advect northward through the afternoon. The favorable thermodynamic
profiles and strong deep layer shear around 45-50 kts will support
potential for supercells. If these storms can become surface based,
they will be capable of all hazards.

Back west near the cold front/low, initial supercells are possible
by the afternoon. These will have potential primarily for large hail
and damaging wind. Boundary parallel deep-layer shear will likely
lead to clustering/upscale growth with time. Strong to extreme
instability is expected ahead of the cold front across portions of
the western Dakotas into the Midwest. As the low-level jet increases
into the evening, it is possible that a corridor of more favorable
damaging wind potential (including significant gusts 75+ mph) may
evolve. For now, confidence in convective evolution is low with a
few CAMs suppressing convection towards the evening along the front
amid the strong EML until later in the evening around 06z.

...Kansas/Oklahoma/Texas...
Isolated high-based thunderstorms are possible near the dryline in
Kansas/Oklahoma/Texas. Moderate instability is expected within this
region with generally weak deep layer shear. This will likely keep
more widespread severe potential low. However, a few stronger storms
may be capable of strong winds given deeply mixed profiles. For now,
this potential remains too isolated to include probabilities.

..Thornton/Chalmers.. 06/29/2026


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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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