SPC Jun 22, 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
0812 PM CDT Sun Jun 21 2026

Valid 220100Z - 221200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST
KS INTO NORTH-CENTRAL OK...

...SUMMARY...
Tornadoes (possibly strong) and damaging winds remain possible this
evening into parts of the Mississippi and Ohio Valleys. A swath of
severe gusts (possibly greater than 75 mph) appears possible later
tonight from southwest Kansas into central Oklahoma.

...Mid MS Valley into the Ohio Valley...
An MCV moving across IN will eventually encounter weaker low-level
moisture and instability with eastward extent. However, a long-lived
storm cluster may continue eastward toward parts of southwest OH and
eastern KY, before a definitive weakening trend occurs. Damaging
wind and embedded tornadoes will remain possible with the primary
storm cluster until weakening occurs. Semi-discrete cells and small
clusters trailing the MCV will also continue to pose a threat of
tornadoes (possibly strong) and damaging winds through the evening,
within a moist and favorably sheared environment. See MCD 1237 for
more information.

...Central High Plains into OK and southern MO...
Widely scattered storm development is underway near a surface
boundary draped from northwest OK into southeast KS/southwest MO.
While large-scale forcing is generally modest at best, MLCAPE of
2500-4000 J/kg and effective shear of 40+ kt are conditionally quite
favorable for organized storms. A few supercells may persist along
the front through the evening, with a threat of large to very large
hail and localized severe gusts. Also, while low-level flow is weak,
vorticity and backed surface winds near the boundary could support
some tornado potential, if a robust supercell can become
established.

Farther northwest, a supercell cluster is ongoing across western KS
this evening. This cluster will continue to pose a threat of large
to very large hail, severe gusts, and possibly a tornado through the
evening. See MCD 1239 for more information regarding the short-term
threat.

Short-term guidance (notably the HRRR and RRFS) suggests that this
cluster will continue to grow upscale, and potentially evolve into
an MCS that will move southeastward across southwest KS into
northwest and central OK, with threat of severe gusts (potentially
above 75 mph) through the overnight hours. This evolution appears
plausible, if evening convection across northwest OK is not too
disruptive to the environment. Given the very favorable midlevel
lapse rates on the 00Z DDC and OUN soundings, rich moisture, and
strong instability and deep-layer shear, a 30%/CIG1 wind area was
added from southwest KS into central OK.

..Dean.. 06/22/2026


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SPC Jun 21, 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
0257 PM CDT Sun Jun 21 2026

Valid 212000Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE CENTRAL HIGH PLAINS TO THE MISSISSIPPI AND LOWER OHIO VALLEYS...

...SUMMARY...
Scattered severe thunderstorms should occur from the central High
Plains into the mid Mississippi and lower Ohio Valleys, mainly this
afternoon into tonight. Large to very large hail, severe/damaging
winds (some 75+ mph), and tornadoes will all be possible. Some
potential for strong tornadoes may develop across parts of Illinois,
and Indiana during the afternoon and evening.

...20z Update Mid MS Valley and lower OH Valley...
Minimal changes were made to the prior outlook given the latest
observational trends. Several clusters of strong thunderstorms are
ongoing ahead of an MCV across the mid MS Valley. An observed messy
convective mode should persist with a mix of bowing structures and
transient supercells likely ahead of the MCV, and near the effective
warm front from eastern IL into IN. Additional storm development is
also possible behind the MCV along the remnant boundary into MO and
eastern KS. This will support a risk for damaging gusts and perhaps
a couple of tornadoes where low-level flow is backed and hodographs
are larger. Eventually upscale growth into one or more bowing
clusters is likely later this evening/overnight into the OH valley
with a continued risk for damaging gusts and embedded tornadoes.

...KS/OK this evening/tonight...
Severe storm development appears probable along the modified
trailing outflow across northwest OK and southwest KS this afternoon
into this evening. Sufficient vertical shear exists for supercells
and organized clusters. With large buoyancy and steep low/mid-level
lapse rates, large hail is likely with these strong updrafts. A
brief tornado or two is also possible, owing to storm interactions
and ambient vertical vorticity along the outflow boundary.

Damaging wind potential will likely increase with storm
consolidation, though the more cellular initial mode suggests this
maybe somewhat gradual. These storms, and additional convection
originating further north from the central High Plains, should
persist overnight into central and southern OK, reaching the Red
River Valley by 12z tomorrow morning with isolated severe potential.

..Lyons.. 06/21/2026

.PREV DISCUSSION... /ISSUED 1110 AM CDT Sun Jun 21 2026/

...MO/IL/IN/KY...
A long-lived band of thunderstorms currently extends from
east-central MO into southwest MO/northeast OK. This activity is
tracking into a region of increasingly warm/moist air where
dewpoints are rising to near 70F and breaks in the clouds are
contributing to moderate CAPE values. All CAM guidance suggests
that storms along the line will intensify this afternoon and track
eastward across southern IL/southern IN and northern KY. Low-level
shear is quite strong, but somewhat veered. This increases
uncertainty of storm mode between discrete supercells or bowing
structures. It appears there will be a period of risk early in the
event for tornadic supercells, followed by multiple linear storm
segments capable of damaging wind gusts. Storms may remain severe
as far east as southern OH and eastern KY overnight. Refer to MD
#1228 for further short-term details.

...MO/KS/OK/AR...
In the wake of the aforementioned convection, an outflow boundary
extends southwestward into central OK. Rapid clearing is occurring
north of the boundary, where residual moisture and steep lapse rates
will quickly destabilize the area. Scattered thunderstorms are
expected to form by late afternoon in this zone and track slowly
southeastward. Sufficient deep-layer shear and high CAPE will
promote the risk of a few supercells capable of large hail and
damaging winds. A tornado or two might also occur.

...NE/CO/KS...
Low clouds are eroding across the NE Panhandle southward into
eastern CO/western KS, where rapid afternoon destabilization should
occur. A weak shortwave trough over eastern WY will rotate into the
region this afternoon, helping to initiate scattered thunderstorms.
Supercells capable of very large hail appear possible, tracking
southeastward across the risk area through mid-evening.


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SPC Jun 21, 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
0740 AM CDT Sun Jun 21 2026

Valid 211300Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI AND LOWER OHIO VALLEYS...

...SUMMARY...
Scattered severe thunderstorms should occur from the central High
Plains into the mid Mississippi and lower Ohio Valleys, mainly this
afternoon into tonight. Large to very large hail, severe/damaging
winds (some 75+ mph), and tornadoes will all be possible. Some
potential for strong tornadoes may develop across parts of Missouri,
Illinois, and Indiana during the afternoon and evening.

...Central Plains to the Mid Mississippi and Lower Ohio Valleys...
An MCS with a convectively augmented parent MCV extends from parts
of central MO into southeast KS/northern OK this morning. The
airmass downstream of this MCS across MO is not particularly
unstable, but greater low-level moisture and related instability is
present across northeast OK and vicinity. Current expectations are
for the MCS/MCV to continue eastward across the mid MS Valley and
Ozarks through the morning while posing an isolated threat for
severe/damaging winds. With time, some re-invigoration of the MCS
appears possible into the lower OH Valley as destabilization occurs
with daytime heating. Trailing outflow from the morning convection
will serve as a focus for additional thunderstorms later today as a
compact/enhanced low-level jet moves eastward from the Ozarks into
the mid MS/lower OH Valleys.

There still appears to be potential for more robust thunderstorm
development this afternoon across these areas along and south of the
outflow boundary/front. Moderate instability will likely develop in
the presence of 30-40 kt of deep-layer shear, which will be
sufficient to support supercells. Enhanced low-level shear will also
be present owing to the eastward-migrating low-level jet. This will
foster a risk for tornadoes with any sustained supercells, and a
strong tornado appears possible. Considered greater tornado
probabilities and a categorical upgrade in a narrow corridor across
parts of MO/IL/IN, but there remains too much uncertainty regarding
sufficient destabilization in the wake of the morning activity. The
severe/damaging wind threat will also increase, with the potential
for multiple clusters to form and track eastward into the lower OH
Valley through the evening and early overnight hours.

Convective development should also occur farther west along/near the
composite outflow boundary/front across the Ozarks into southern
KS/northern OK by peak afternoon heating. Strong instability and
moderate deep-layer shear will likely support updraft organization
and a mix of supercells and multicell clusters. Large to very large
hail should be the primary threat initially, but deep-layer shear
vectors aligned largely parallel to the boundary should foster
convective mergers and an increasing threat for severe/damaging
winds with multiple clusters that should form and spread
east-southeastward across OK and the Ozarks through the evening. At
least an isolated severe wind threat may persist overnight with
southward extent across the southern Plains into AR given the large
degree of buoyancy forecast.

A mid-level shortwave trough over WY this morning will move
east-southeastward towards the central High Plains by this
afternoon. Enhanced westerly flow aloft attendant to this shortwave
trough will overspread the central High Plains through the day. A
convectively reinforced front extends from northwest OK into the
central High Plains, and modest low-level upslope flow is forecast
to the north of this boundary today. Recent short-term guidance
continues to suggest that moderate instability will develop with
filtered daytime heating in the presence of steep mid-level lapse
rates and strong effective bulk shear. Isolated supercells that can
develop in this regime across eastern CO into western NE/KS should
pose mainly a large to isolated very large (2+ inches) hail risk
initially, before some clustering/upscale growth possibly occurs
this evening. Scattered severe/damaging winds would become an
increasing concern if this mode transition occurs, and isolated
significant gusts (75+ mph) appear possible.

..Gleason/Broyles.. 06/21/2026


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SPC Jun 21, 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 20 2026

Valid 210100Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
KANSAS...

...SUMMARY...
Severe thunderstorms remain likely across parts of the central
Plains this evening into late tonight. Large hail, severe winds
(some 75+ mph), and a few tornadoes are possible.

...Central Plains...
An intense supercell cluster over northwest KS is expected to grow
at least modestly upscale with time this evening, and spread
east-southeastward across parts of northern/central KS, while more
isolated supercells may evolve across southwest KS and move toward
south-central KS through at least dusk. MLCAPE of near/above 2000
J/kg and effective shear of 50+ kt will continue to support
organized storms with large hail (potentially 2+ inches in diameter
with any sustained supercells), severe wind gusts (possibly 75+
mph), and some tornado potential, especially with storms that
persist into richer low-level moisture across central/eastern KS.
Storm evolution remains somewhat uncertain overnight into eastern KS
and western MO, but a storm cluster and possible MCS may continue
through the end of the period, with severe-wind potential, and some
hail and tornado threat with any embedded supercells.

Farther northeast, elevated supercells may continue to pose a threat
of hail and isolated strong to severe gusts from southeast NE into
northeast KS through dusk. See MCD 1215 for more information.

To the west, a cluster of storms with a history of measured severe
gusts is moving into parts of southwest SD and the NE Panhandle.
Increasing CINH with time and eastward extent should result in a
gradual weakening trend, though some severe threat will remain
possible into mid/late evening across the NE Sand Hills region. See
MCD 1218 for more information.

Some threat for isolated supercells may persist farther south into
northeast CO through dusk, with a threat of hail. Other remnant
high-based convection may pose a threat of localized severe gusts
through dusk across parts of western/central WY.

..Dean.. 06/21/2026


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