Mesoscale Discussion 1267
NWS Storm Prediction Center Norman OK
1251 AM CDT Tue Jun 23 2026

Areas affected...southern into southwest Oklahoma across the Red
River into far northern Texas

Concerning...Severe potential...Watch unlikely 

Valid 230551Z - 230915Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms may increase in coverage across southern Oklahoma
into parts of far northern Texas across the Red River. A few storms
may become severe with locally large hail.

DISCUSSION...Scattered storms have developed within a zone of weak
theta-e advection at 850 mb, from southwest OK into northeast TX.
Rich boundary layer moisture as well as overall strong instability
exists in this region, along with effective deep-layer shear of
35-40 kt. Area VWPs indicate 850 winds out of the south/southeast at
around 25 kt, aiding lift across the warm advection zone. Models
suggest low-level winds will veer and strengthen tonight, which may
briefly increase ascent through about 10Z. Slow-moving cells with
periodic hail cores and heavy rain are expected. Given high PWAT
environment, localized strong downbursts may occur as well.

..Jewell/Gleason.. 06/23/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...SHV...TSA...FWD...OUN...LUB...AMA...

LAT...LON   33619781 33829949 34000001 34240023 34640027 34950021
            35309986 35419912 35289852 34999805 34689723 34269579
            33989482 33759454 33379448 33139485 33349608 33619781 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0105 AM CDT Tue Jun 23 2026

Valid 231200Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL HIGH PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE MID ATLANTIC...

...SUMMARY...
Severe storms capable of 2+ inch diameter hail, 75+ mph gusts, and
isolated tornadoes are expected from the central High Plains into
parts of the central and southern Plains today into tonight.
Damaging gusts and perhaps a brief tornado may occur with storms
along the Mid-Atlantic. Scattered storms capable of isolated severe
wind/hail are possible across the northern Plains into the upper
Mississippi Valley.

...Synopsis...
A mid-level trough will impinge on the Eastern Seaboard while upper
ridging builds over the western into central CONUS today. Multiple
mid-level impulses are poised to traverse the upper ridge,
supporting at least scattered thunderstorm development in multiple
rounds across the Plains. These rounds of storms will encompass the
entire period (12Z Tuesday morning through 12Z Wednesday morning),
resulting in a complex forecast. Nonetheless, stronger flow aloft
associated with the ridge will advect an EML atop seasonal low-level
moisture, resulting in enough buoyancy and vertical wind shear to
support an appreciable severe threat, especially over the central
High Plains. Otherwise, a cold front approaching the East Coast will
support a line of severe thunderstorms over the Mid-Atlantic.

...Portions of the central High Plains...
By afternoon peak heating, upslope flow beneath a glancing mid-level
impulse will support the initiation of at least isolated storms.
These storms will develop atop a relatively mixed boundary layer and
surface dewpoints approaching 60 F, overspread by 9 C/km mid-level
lapse rates, resulting in moderate to locally strong buoyancy (i.e.
3000+ J/kg MLCAPE). Strong vertical wind shear will also be in
place, with 50 kts of effective bulk shear driven by elongated
hodographs with modest low-level curvature. Supercells will be the
primary storm mode, accompanied by a threat for all hazards. Given
the potential for a mixed boundary layer, intense gusts well
exceeding 75 mph will be possible, in addition to hailstones
potentially reaching the 2-3.5 inch range. Any supercells that can
ingest terrain-induced low-level vertical vorticity may be
accompanied by a landspout/hybrid tornado threat.

...Portions of the central and southern Plains...
A surface boundary currently resides along the Red River, with
thunderstorms developing all along this boundary from the TX
Panhandle to central MS. At the start of the forecast period (12Z
Tuesday), an established low-level jet will be in the process of
transporting a moist low-level airmass northward, perhaps
encouraging northward movement of the surface boundary as well.
However, an MCS may be develop somewhere along the KS/OK border at
the start of the period along an elevated boundary, which will drift
southeastward through the late morning/early afternoon hours. The
evolution of this MCS and interacting convection with the
aforementioned surface boundary introduces considerable uncertainty
to the forecast, especially for late afternoon/early evening storms.

If the MCS and merging surface boundary convection linger over the
southern Plains through the day, later severe potential may be
reduced. However, if convection can exit the Plains or somehow
dissipate by late morning/early afternoon, enough destabilization
may take place for an evening severe threat. Should the later
scenario unfold, convective initiation over the southern High Plains
may result in severe hail/wind producing supercells merging into a
cold-pool driven MCS, which in turn may produce a severe wind swath
with 75+ mph gusts. Given so much uncertainty with the details of
this forecast, a broad area of 15 percent/CIG1 probabilities were
introduced for portions of the central and southern Plains.
Considerable adjustments to this forecast (upgrades or probabilities
removal) may be needed depending on convective and subsequent
modified environmental evolution through the first half of the
period. 

...Parts of the Northern Plains...
Cold temperatures aloft and 8+ C/km mid-level lapse rates will
accompany the passage of an upper-low over parts of the northern
Plains into the Upper MS Valley. By afternoon peak heating,
thunderstorms initiating along the periphery of the upper low, amid
a belt of stronger flow aloft (driving elongated hodographs) will
support multicells and perhaps transient supercells capable of
isolated severe wind and hail.

...Mid-Atlantic...
By late morning into early afternoon, surface temperatures warming
into the 80s F amid 70+ F dewpoints will yield over 2000 J/kg
MLCAPE, but distributed through tall/thin profiles given poor (5-6 
C/km) mid-level lapse rates. Nearly unidirectional tropospheric wind
profiles will yield nearly 40 kts of effective (speed) shear, which
will favor multicellular development and ultimately a squall line
along/ahead of the cold front. Damaging gusts are expected to be the
main threat, though a brief tornado may also occur wherever locally
backed near-surface winds may be realized.

..Squitieri/Halbert.. 06/23/2026

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0109 AM CDT Tue Jun 23 2026

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL/SOUTHERN HIGH PLAINS....

...SUMMARY...
Widely scattered severe storms are possible across the central High
Plains on Wednesday with a threat for large to very large hail and
severe wind gusts.  More isolated severe storms are possible across
portions of the Upper Midwest, Ozarks to Mississippi, and across
northern Utah.

...Synopsis...
Moderate northwesterly mid-level flow will be present from the
northern Rockies to the Midwest between a ridge across the Southwest
and a trough moving across southern Canada into the Upper Midwest. A
weak mid-level shortwave trough will likely be in the Arkansas
region at the beginning of the period and weaken with a secondary
mid-level shortwave trough moving across the central Rockies and
deamplifying the ridge. At the surface, a weak surface low will move
from northern Minnesota into Wisconsin. A secondary lee cyclone will
develop across eastern Colorado in response to the approaching
mid-level shortwave trough and strengthening mid-level flow. 

...Central/southern High Plains...
Moderate to strong instability is forecast to develop within upslope
flow across eastern Colorado and southeast Wyoming on Wednesday
afternoon. As 40 to 50 knots of mid-level flow advects over the
region, a favorable supercell environment will be in place.
Supercells are likely to develop by mid afternoon with an initial
threat of large to very large hail and severe winds. The more
organized supercell threat is forecast from east-central Colorado
northward where the 15% hail probabilities are confined. 15% wind
probabilities continue farther south as forecast soundings suggest
severe winds (perhaps 75+ mph) are likely, even if storms are less
organized.

...KS/OK into the Ozarks...
Day 1 convection will have a considerable impact on the coverage and
severity of severe storms on Wednesday. Some guidance shows morning
storms along a frontal zone in Oklahoma and persisting into the
afternoon which will stabilize most of the region into the afternoon
and evening. However, if these storms do not form, a very favorable
airmass will remain in place and a MCS could develop across the High
Plains and move into this region Tuesday night. This could bring
some severe weather threat and it would have implications for where
destabilization would be on Day 2/Wednesday. Therefore, a broad 5%
driven by severe winds seems appropriate at this time and additional
refinement can be made once the impact of prior day convection
becomes more clear. 

...Western Great Lakes...
Lingering clouds associated with early-day storms may limit air mass
destabilization into afternoon. However, where cloud breaks can
occur, the combination of cooling temperatures aloft and modest
boundary-layer moisture content will support moderate afternoon
instability. Widely scattered thunderstorms are expected to develop
during the afternoon in the vicinity of the surface low and frontal
boundary, and within the belt of stronger mid-level flow, suggesting
some potential for large hail with the strongest updrafts.

...Eastern Arkansas into Mississippi...
There is considerable uncertainty regarding the coverage of storms
across Arkansas at 12Z Wednesday, but given forcing from a mid-level
trough and moderate to strong instability across the region, either
re-intensification of morning convection or additional afternoon
convection is possible within this zone. Damaging winds will be the
primary threat.

...Northern Utah...
A weak mid-level shortwave trough will move across northern Utah
during the day on Monday with weak to moderate instability. Forecast
soundings show a deeply-mixed sub-cloud layer which may result in
severe winds. Some consideration was given to a CIG1 area given the
potential for organized storms in the steep lapse rate environment,
but did not have the confidence for 75+ mph wind gusts to add it at
this time.

..Bentley.. 06/23/2026

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1226 AM CDT Tue Jun 23 2026

Valid 231200Z - 241200Z

...CRITICAL FIRE WEATHER AREA FOR NORTHERN ARIZONA AND SOUTHERN
UTAH...

...Synopsis...
Dry southwesterly to westerly flow under a building ridge aloft will
bring a broad fire weather concern to portions of the Southwest,
southern Great Basin and CO Plateau today. Hot temperatures combined
with dry air will drop RHs to 5-15% during peak heating across this
region this afternoon. This well-mixed boundary layer will transport
the aforementioned flow to the surface, leading to widespread
west-southwest winds of 10-15 mph over the Elevated area. To capture
the areal extent of this activity as indicated in the latest
forecast guidance, slight expansions were made to include additional
portions of central NV and southwestern WY. A corridor of enhanced
westerly winds up to 20 mph amid RH as low as 10% will yield a
period of critical fire weather conditions for parts of northern AZ
into southern UT. Persistently poor RH nighttime recoveries will
further exacerbate already very dry fuels and extend burn periods
well into the overnight hours.

While not likely, a thunderstorm or two cannot be completely ruled
out near Flagstaff, AZ. If any such storm does form, it will likely
provide more potential for wind than rain given the high cloud
bases, limited precipitable water, and very hot and dry surface
conditions in this area. Greater potential for thunderstorm activity
will exist on Day 2/Wednesday.

..Stearns.. 06/23/2026

...Please see www.spc.noaa.gov/fire for graphic product...