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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SPC Jun 27, 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
0700 AM CDT Sat Jun 27 2026

Valid 271300Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON INTO EARLY TONIGHT ACROSS EASTERN MT AND WESTERN ND...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS INTO WESTERN SOUTH
DAKOTA AND NEBRASKA...AND ACROSS NORTH CAROLINA...

...SUMMARY...
A mix of initial supercells and later storm clusters will produce
swaths of severe outflow winds and very large hail across the
northern High Plains late this afternoon into early tonight.

...Northern High Plains this afternoon into tonight...
Water-vapor imagery this morning shows a mid- to upper-level low
over the Vancouver/Washington coast with a large-scale trough
enveloping much of the West. Strong cyclonic 500-mb flow will
extend through the base of the trough and into parts of the northern
High Plains later today coincident with the ejection of a lead
disturbance into the western Dakotas. Boundary-layer dewpoints in
the 60s will continue to spread northward from KS/NE to the Dakotas,
east of a deep lee trough/cyclone across the central/northern High
Plains. The moistening will occur beneath a plume of steep midlevel
lapse rates emanating from the Great Basin and north-central
Rockies.

Morning showers and thunderstorms over parts of this region will
move downstream and away from where strong to severe thunderstorm
development is expected later this afternoon, along both the
surface trough/lee cyclone near the MT/ND border and near the Big
Horn Mountains. Some of the stronger initial storms will likely be
supercellular owing to moderate to large CAPE. The risk for large
to very large hail (2-3 inches in diameter) is greatest near the
ND/MT border where supercells are forecast early in the convective
life cycle. A couple of tornadoes are also possible but relatively
large temperature-dewpoint spreads and a transition to upscale
growth may temper the tornado threat. As more storms develop
leading to storm mergers and coalescing outflow, a linear cluster
may potentially develop into a bow echo across western ND this
evening. The NSSL-WRF and some recent HRRR time-lagged solutions
imply this scenario but uncertainty remains due to appreciable model
spread. Nonetheless, the very unstable airmass over western ND
combined with a supercell to linear cluster transition in the
presence of steep low to mid-level lapse rates, lends confidence in
highlighting a corridor over western ND in a level 2 intensity
(locally 80-100 mph gusts). More isolated supercells will also be
possible farther south into western SD/NE where isolated very large
hail and significant severe outflow gusts will be possible.

...TN/southern KY to NC this afternoon...
A series of MCVs in a corridor from south-central KS into MO and
east near the WV/VA border will provide a focus for additional
thunderstorm activity through the day. In areas void of morning
showers/thunderstorms, a very moist boundary layer featuring lower
to mid 70s F surface dewpoints will gradually heat and destabilize
through the mid afternoon. Some enhancement of midlevel flow in
proximity to the MCVs may aid in storm organization primarily in the
form of multicellular clusters. Isolated to widely scattered wind
damage will be the primary risk with this activity, but an isolated
tornado may also occur in the warm advection zone with enhanced
low-level hodograph curvature across TN on the southwest flank of
the western MCV, though confidence in this scenario remains low.

...TX Panhandle into west TX 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.

..Smith/Jewell.. 06/27/2026


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SPC Jun 27, 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
1233 AM CDT Sat Jun 27 2026

Valid 271200Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON INTO EARLY TONIGHT ACROSS EASTERN MT AND WESTERN ND...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS INTO WESTERN SOUTH
DAKOTA AND NEBRASKA...AND ACROSS NORTH CAROLINA...

...SUMMARY...
A mix of initial supercells and later storm clusters will produce
swaths of severe outflow winds and very large hail across the
northern High Plains late this afternoon into early tonight.
Isolated wind damage will also be possible from the Mid-Mississippi
Valley to the Carolinas, as well as across west Texas and the Texas
Panhandle.

...Northern High Plains this afternoon into tonight...
Embedded speed maxima will rotate northeastward over the northern
High Plains, around the eastern periphery of a close midlevel low
evolving over the northern Great Basin and northern Rockies.
Boundary-layer dewpoints in the 60s will continue to spread
northward from KS/NE to the Dakotas, east of a deep lee
trough/cyclone across the central/northern High Plains. The
moistening will occur beneath steep midlevel lapse rates, which
combined with daytime heating will result in large CAPE.

Thunderstorm development is expected this afternoon along both the
surface trough/lee cyclone near the MT/ND border and near the Big
Horn Mountains. The initial storms could be supercells with very
large hail (2-3 inch diameter) near the ND/MT border, and a couple
of tornadoes with any supercells anchored along the surface
boundary, though relatively large temperature-dewpoint spreads and
mode concerns could temper the tornado threat somewhat. By late
evening and early tonight, storms will likely grow upscale and move
northeastward across ND as one or more MCSs with severe outflow
winds (potentially 80+ mph) in the steep lapse rate environment.
More isolated supercells will also be possible farther south into
western SD/NE where isolated very large hail and significant severe
outflow gusts will be possible.

...TN/southern KY to NC this afternoon...
An MCV now over eastern KY will continue eastward near the VA/NC
border during the day, and additional MCVs are likely to emerge from
ongoing storm clusters moving eastward across OK, southwest KS and
the TX Panhandle. Ascent with the MCVs, as well as residual
outflow/differential heating zones, will help focus thunderstorm
development during the afternoon in a moist, unstable environment.
Occasional wind damage will be possible with storm clusters where
low-level lapse rates are relatively steep (south of persistent
clouds) and there is some enhancement of midlevel flow. An isolated
tornado may also occur in the warm advection zone with enhanced
low-level hodograph curvature across TN on the southwest flank of
the western MCV, though confidence in this scenario is low.

...TX Panhandle into west TX 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.

..Thompson/Chalmers.. 06/27/2026


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SPC Jun 27, 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
0802 PM CDT Fri Jun 26 2026

Valid 270100Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS INTO EARLY TONIGHT
FROM THE HIGH PLAINS INTO NORTHERN OKLAHOMA AND SOUTHERN MISSOURI...

...SUMMARY...
Scattered severe thunderstorms with severe outflow gusts and large
hail will persist into early tonight across the High Plains and from
northern Oklahoma into southern Missouri.

...Northern OK to southern MO...
Multiple strong-severe storms formed late this afternoon along a
stalled front from the northeast TX Panhandle eastward into northern
OK into southern MO. Seasonably high moisture content in the
boundary layer (dewpoints in the low-mid 70s) and lingering warm
temperatures are contributing to MLCAPE near 3000 J/kg with only
weak convective inhibition, while vertical shear is sufficient for
supercells with large hail (1 to 2 inches in diameter). Storms will
likely persist into tonight as a result of cell interactions and an
increase in warm advection with a strengthening low-level jet,
immediately downstream from a subtle midlevel trough now approaching
northwest OK. The stronger cells/clusters will be capable of
isolated large hail and occasional severe outflow gusts of 60-70 mph
as storms spread slowly southeastward across
northern/central/northeast OK.

A similar environment extends into southern MO along and south of
the stalled front, with a few ongoing cells/clusters. There has
been some localized tornado threat across south central MO where a
discrete storm or two are interacting with a zone of slightly
enhanced low-level shear in a moist environment, though the tornado
threat will remain localized/marginal.

...High Plains...
Widely scattered storm clusters formed this afternoon and continue
to develop this evening with interacting outflows from MT across
eastern WY/NE Panhandle into eastern CO and the western OK Panhandle
on the west edge of the moisture in a largely upslope flow regime.
This corridor is downstream from a pronounced midlevel trough over
the Great Basin/Pacific Northwest, which will encourage a nocturnal
low-level jet to support some persistence of storms into early
tonight, despite weakening buoyancy and increasing inhibition with
eastward extent. Occasional severe outflow gusts and large hail
will be the main threats.

Potential for storms to maintain a wind/hail threat a little deeper
into the overnight hours will be across southwest KS and vicinity.
The storm clusters spreading eastward from CO will encounter
somewhat richer low-level moisture (mid-upper 60s dewpoints) on the
immediate cool side of a stalled front, coincident with a nocturnal
increase in the low-level jet and associated warm advection.

...KY area...
A remnant MCV is moving eastward over western KY with the primary
storm cluster from far southern IN into central KY on the leading
edge of the ascent. These storms have exhibited a primarily linear
mode with a trailing cold pool into western KY. Earlier discrete
storms have since weakened while moving atop the rain-cooled air,
though a few storms may persist into early tonight in the warm
advection regime on the southwest flank of the MCV. The primary
severe threat appears to be isolated wind damage with the leading
line segments across central/northern KY for the next 1-2 hours
before boundary-layer stabilization weakens the storms.

..Thompson.. 06/27/2026


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