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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SPC Jun 28, 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 Sat Jun 27 2026

Valid 280100Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH EARLY
TONIGHT ACROSS WESTERN NORTH DAKOTA AND VICINITY...

...SUMMARY...
The threat for isolated very large hail (2+ inches in diameter) and
swaths of severe outflow gusts (potentially exceeding 80 mph) will
persist through early tonight across the Dakotas and far eastern
Montana. A couple of tornadoes will also be possible with lingering
supercells this evening and embedded circulations within the larger
clusters.

...Northern Plains...
Thunderstorms have been growing upscale into the primary cluster
over southwest ND, with additional frontal convection into eastern
MT and another cluster moving off the lee trough in southwest SD.
Vertical shear and buoyancy remain favorable for supercells with
isolated very large hail, though the clear trend to the expected
cluster/linear mode suggests that severe outflow gusts of 60-85+ mph
will be the main threat across the western Dakotas through early
tonight. A few tornadoes are still possible late this evening with
lingering supercells from west central ND to northwest NE per the
00z BIS and LBF soundings, though the threat will transition more to
embedded circulations within line segments across SD/ND. The ND
cluster is expected to weaken late tonight across central/eastern
ND, while the SD cluster may persist longer in a strengthening warm
advection regime, though the severe threat will slowly diminish with
eastward extent as the convection becomes elevated.

...Eastern MO to KY/TN...
Multiple, remnant MCVs are moving eastward from eastern MO across KY
to NC. Prior convection has overturned much of NC, where the threat
for wind damage has diminished. There will still be a low-end wind
damage threat where the MCVs move along the northern gradient of
somewhat larger buoyancy from eastern MO to KY/TN. A brief tornado
may also occur in the short term with supercell structures in the
warm advection zone where low-level shear is slightly enhanced on
the southwest flank of the primary MCV moving across KY.

...West TX/southeast TX Panhandle in the short term...
Only isolated deep convection has formed as of this evening across
the Pecos Valley and near CDS. Lingering hot surface temperatures
and inverted-V profiles could still support isolated severe outflow
gusts through about 02-03z.

..Thompson.. 06/28/2026


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SPC Jun 27, 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
1142 AM CDT Sat Jun 27 2026

Valid 271630Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN HIGH PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
TENNESSEE VALLEY TO CAROLINAS...

...SUMMARY...
Severe thunderstorms are likely today across the northern High
Plains including northeast Wyoming and eastern Montana into the
western Dakotas, with storms capable of very large hail, very strong
outflow winds (80+ mph), and tornadoes late this afternoon into
tonight.

...Northern High Plains this afternoon into tonight...
A rather active severe-weather scenario is anticipated regionally
later today, including the potential for intense/locally significant
severe storms. A lead shortwave trough/speed max will continue to
approach through late today, with the exit region of a strong
upper-level jet overspreading the region including 50+ kt
southwesterlies above 5km AGL. Boundary-layer dewpoints in the 60s F
will continue to spread northward regionally, to the east of a
deepening surface low across northeast Wyoming toward the far
western Dakotas, and a sharpening lee trough/dryline across a more
prevalent north/south extent of the High Plains. This low-level
moistening will occur beneath a plume of steep mid-level lapse rates
emanating from the Great Basin and north-central Rockies.

Initial surface-based development is expected near the surface
low/trough near the Big Horn Mountains toward the
Wyoming/Montana/North Dakota border vicinity. The maturing stronger
initial storms will almost certainly be supercellular owing to
moderate to large CAPE and a strong wind field. The risk for large
to very large hail (2-3 inches in diameter) is greatest near this
aforementioned border region where supercells are forecast early in
the convective life cycle, although additional/somewhat more
discrete development will also likely occur a bit later farther
southeastward across northwest South Dakota.

A few tornadoes are also possible particularly in the more
moisture-rich environment near the surface triple point, but
relatively large temperature-dewpoint spreads and a transition to
upscale growth may temper the tornado threat, particularly with
northward extent either side of the Montana/North Dakota border
vicinity. As more storms develop leading to storm mergers and
coalescing outflow, a linear cluster will likely develop into a
maturing/accelerating bow echo into western North Dakota this
evening, with significant/intense thunderstorm winds (80+ mph)
possible.

Severe storms will likely develop eastward tonight across the
Dakotas, and prior to that, diurnally enhanced, but more isolated
intense, development is plausible as far south as western Nebraska
with large hail and damaging winds.

...Northern Intermountain West including northern UT/western WY...
Influenced by a lead shortwave trough/speed max associated with the
prominent upper-level trough centered over the Pacific Northwest,
strong to locally severe thunderstorm potential will probably exist
early today. The prolifically strong wind field and modest
destabilization will tend to focus today across northern Utah,
southeast Idaho into western Wyoming, including the Star Valley
vicinity. Severe-caliber wind gusts and some hail may occur.

...Mid-South/Tennessee/southern Kentucky to North Carolina...
Multiple MCVs, including across far south-central Missouri and
southeast Kansas at midday, will influence the region as they
progress east-southward generally toward Kentucky and Tennessee.
Related flow enhancement is evident in regional WSR-88d VWP data,
and particularly in the 12z Lamont, OK observed sounding (40+ kt
4-9km AGL). See Mesoscale Discussion 1346 for additional short-term
details.

These MCVs will influence and semi-focus thunderstorm development
within a moist and increasingly unstable boundary layer from the
southeast Missouri/northeast Arkansas border vicinity into Kentucky
and Tennessee. This includes the possibility of some supercells and
well-organized clusters in the presence of 35-40 kt effective shear.
Pockets of wind damage will be the most common risk, but some
tornado potential will exist as well. Additional severe storms
capable of wind damage are also expected farther eastward into the
Carolinas this afternoon through around mid-evening.

...Texas Panhandle/West Texas late this afternoon/evening...
Though forcing for ascent will be weak at best this far south,
strong surface heating/mixing along the lee trough/dryline could
support high-based thunderstorm development late this afternoon.
Inverted-V profiles will favor the potential for isolated severe
outflow gusts of 60-75 mph.

..Guyer/Supinie.. 06/27/2026


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