RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Thu Jul 23 07:30:02 UTC 2026.
No Mesoscale Discussions are in effect as of Thu Jul 23 07:30:02 UTC 2026.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 AM CDT Thu Jul 23 2026
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
WESTERN KANSAS...
...SUMMARY...
Widely scattered severe storms capable of severe wind gusts and
large hail are possible over portions of the central and southern
High Plains Thursday afternoon and evening. More isolated
occurrences of damaging wind are possible from the middle Texas
coast into Deep South Texas, the eastern Carolinas, and parts of the
Columbia Basin into the northern Rockies.
...Synopsis...
A short-wave trough over the central Rockies late this evening is
forecast to progress slowly into the central High Plains by Thursday
afternoon, within the northeast periphery of a strengthening
mid/upper-level high over the southern Rockies. Downstream from
those developments, a short-wave trough will translate through New
England with a trailing vorticity ribbon and associated belt of
enhanced mid-level flow across the southern Mid-Atlantic. Elsewhere,
Tropical Storm Bertha is forecast to advance from just off the
southwest LA coast to the middle TX coast by Thursday evening.
At the surface, a stationary front currently extending from the CO
Front Range through the OK and TX Panhandles into the Red River
Valley is forecast to drift north through portions of western KS on
Thursday immediately ahead of a thermal low/lee cyclone over
southeast CO and southwest KS. A dryline will extend south from the
surface low-front triple point into the central or eastern OK and TX
Panhandles by mid- to late afternoon.
...Central and southern High Plains...
Strong boundary-layer heating is forecast in the vicinity of the
surface front and dryline Thursday afternoon with temperatures in
the mid 90s to around 105. The hot temperatures will combine with
dewpoints in the mid 50s to mid 60s and modestly steep mid-level
lapse rates to yield a narrow axis of moderate instability with
MLCAPE of 1500-2500 J/kg. Forcing for ascent preceding the
short-wave trough is expected to contribute to isolated to widely
scattered thunderstorms by mid afternoon from the vicinity of the
thermal low in southeast CO to along the front and dryline from
northeast CO into the OK and TX Panhandles.
Forecast soundings along the front indicate a vertically veering
wind profile with 30-35 kt of deep-layer shear, which will be
sufficient for at least episodic supercell structures with a risk
for large hail. In contrast, the storms forming in the hot, deeply
mixed air mass west of the boundary are more likely to produce
sporadic severe wind gusts. A corridor of potentially more
concentrated severe wind gusts may materialize across portions of
southwest KS by evening, where a number of the 00z CAMs indicate the
evolution of an organized cold pool.
...Middle Texas Coast to Deep South Texas...
A channel of enhanced mid-level flow is forecast to precede Bertha
atop a hot and moist boundary layer, with moderate instability
developing by afternoon along the middle TX coast. Similar to
Wednesday, widely scattered thunderstorms are expected during the
afternoon within an environment characterized by 30-40 kt of
deep-layer shear, steep low-level lapse rates, and high PW content.
As such, the potential will exist for locally damaging downburst
winds as storms spread southwest along the coast into Deep South TX
during the afternoon and evening hours.
...Columbia Basin into northern Rockies...
Mid/upper-level winds are forecast to strengthen across the area on
Thursday in tandem with a subtle disturbance moving through portions
of OR and WA. Daytime heating along favored terrain in conjunction
with the glancing influence of the passing disturbance will aid in
isolated to widely scattered thunderstorms by mid afternoon within a
moderately unstable and steep lapse rate environment. The
strengthening upper-level winds will enhance vertical shear,
supporting the potential for some storm organization with an
associated risk for locally damaging wind gusts and marginally
severe hail.
...Eastern Carolinas...
Thunderstorms are expected to be ongoing at 12Z Thursday along a
west-to-east-oriented front in NC. Breaks in the clouds south of the
early-day storms will combine with a moist boundary layer to yield
an axis of moderate instability by afternoon across portions of
southeast NC into far eastern SC. A corridor of more concentrated
thunderstorm development is possible in that area, near the
intersection of the outflow from the morning storms with the
sea-breeze boundary. Modest deep-layer shear will coincide with
steepening low-level lapse rates and high PW content to yield
locally intense wet microbursts capable of damaging winds.
..Mead/Weinman.. 07/23/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 AM CDT Thu Jul 23 2026
Valid 241200Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
NORTH DAKOTA INTO NORTHWEST MINNESOTA...
...SUMMARY...
Isolated severe thunderstorms are possible on Friday across portions
of the Dakotas into northern Minnesota.
...Dakotas into northern MN...
Strengthening northwesterly flow aloft will overspread the region
Friday afternoon into early Saturday in response to a shortwave
upper trough moving across Manitoba/western Ontario and the northern
Great Lakes. At the surface, a front will develop south/southeast
across parts of north Dakota and northern MN.
South/southwesterly low-level flow ahead of the front will transport
modest boundary layer moisture northward across parts of ND/SD and
northern/central MN. This will occur on the eastern periphery of a
strong upper ridge building over the Rockies/High Plains. As a
result of upper ridging, warm temperatures in the 850-700 mb layer
may result in at least weak capping over portions of the region.
Nevertheless, a plume of steep midlevel lapse rates will support
moderate destabilization (1000-2000 J/kg MLCAPE).
Vertically veering wind profiles, also increasing in speed with
height, will result in supercell wind profiles. Forecast soundings
show a well-mixed boundary layer, with steep 0-3 km lapse rates.
Organized cells are expected to develop by late afternoon near the
surface boundary and spread east/southeast with time through the
evening. A low-level jet is also forecast to increase during the
evening/nighttime hours. The main risk with these storms will be
from large hail and strong to severe wind gusts. If storms can
become surface-based, a tornado or two also could occur. The
strengthening low-level jet could maintain elevated convection into
the nighttime hours across northern MN, but instability weakens an
inhibition increases with south and east extent across the Upper MS
Valley. This should keep severe potential relatively confined within
a narrow corridor across portions of the Dakotas into northern MN.
...SC vicinity...
Isolated to scattered thunderstorms are expected Friday afternoon
within a moderately unstable and very moist airmass. Vertically
veering flow, increasing to around 20-30 kt around 1-3 km will
provide around 25 kt effective shear as a surface boundary sags
south and east across the region. This may be sufficient for a
couple of organized clusters capable of producing sporadic wind
damage.
..Leitman.. 07/23/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0130 AM CDT Thu Jul 23 2026
Valid 251200Z - 261200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorm potential appears limited on Saturday.
...Northern High Plains to Upper Midwest...
An amplified upper ridge will remain centered over the High Plains
on Saturday. Moderately enhanced west to northwesterly flow aloft
will overspread portions of the region near the crest of the ridge
and into the Upper MS Valley. Forecast guidance depicts one or more
shortwave impulses rounding the ridge from eastern MT into the
Dakotas, and possibly parts of the Upper Midwest. Forecast soundings
indicate capping across the Upper Midwest, which may limit
thunderstorm potential despite a moistening boundary layer with
time.
Further west across eastern MT into the western Dakotas, low-level
moisture will be limited. However, steep midlevel lapse rates will
result in weak destabilization as strong heating occurs during the
day. Deep boundary layer mixing is forecast, and isolated to
scattered high-based convection could develop within the weakly
unstable airmass. Some potential for strong gusts will accompany
this activity, but it is unclear if sufficient instability and
moisture will exist to support severe wind gusts.
..Leitman.. 07/23/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Thu Jul 23 2026
Valid 261200Z - 311200Z
...DISCUSSION...
...Days 4-5/Sun-Mon -- Upper Midwest toward the Ohio Valley...
Enhanced northwesterly flow aloft will overspread the Upper Midwest
to the Ohio Valley on Sunday and Monday as several shortwave
impulses migrate through the area on the eastern periphery of a
strong upper ridge over the Plains. A seasonally very moist airmass
will reside across much of these areas, supporting strong
destabilization each day. On Sunday, a corridor of severe
thunderstorm potential appears possible across parts of MN/WI toward
northern IA/IL as a weak shortwave impulse initially over the
Dakotas spreads east. While details regarding storm coverage remain
uncertain, sufficient deep layer shear and strong instability will
be in place, and at least isolated storm clusters could pose a risk
for damaging winds.
By Monday, an upper shortwave trough will emanating from an upper
low near Hudson Bay will dig southward across the Great Lakes. This
will result in increasing northwesterly flow aloft. Meanwhile, a
surface low may move eastward across the Great Lakes near the
international border while a stronger nocturnal low-level jet
develops over parts of the Great Lakes and Ohio Valley. This
stronger flow will overspread a moist and unstable airmass, and
potential for thunderstorm clusters developing into an MCS appears
possible.
While details remain uncertain regarding convective evolution and
coverage on Sunday and Monday, through broader synoptic pattern
appears favorable for at least isolated severe thunderstorms. The 15
percent severe areas may shift some in the coming days as details
become more clear.
...Days 6-8/Tue-Thu...
It is possible some severe potential could shift east/southeast on
Tuesday toward the central Appalachians and the Mid-Atlantic.
Deep-layer northwesterly flow will not be as strong as prior days,
but could still be sufficient for some organized severe risk.
Confidence in where greater risk corridors may develop is low, and
will largely be influenced by convective evolution in the Days
4-5/Sunday-Monday periods.
A strong upper ridge will shift west across the western U.S. late in
the period, bringing a broad area of generally weak deep-layer
northwesterly flow to the eastern half of the CONUS. Some
thunderstorm potential is likely within this typical summertime
pattern across the Plain into the East, but severe potential is
uncertain.
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1222 AM CDT Thu Jul 23 2026
Valid 231200Z - 241200Z
...Synopsis...
Upper-level troughing will continue across the eastern U.S. as
surface high pressure builds into the Ohio Valley. A long-lived
upper ridge across the western U.S. will finally begin to flatten
and break down owing to an approaching eastern Pacific upper trough.
Within the last 24 hours, mixed wet/dry thunderstorms have traversed
portions of central Oregon and the Cascades. Only localized areas
received appreciable precipitation, not fully mitigating fuel
concerns across the broader environment. Returning dry and windy
conditions east of the Cascades will further enhance the fuelscape,
encouraging lightning-induced ignitions to emerge and further
exacerbating numerous wildfires across the region.
...Pacific Northwest and Northern Rockies...
As upper-level flow transitions from broadly southerly to
southwesterly, monsoonal moisture will be shunted northeastward as a
dry airmass returns to the Inland Northwest. Daytime
destabilization, ample mid-level moisture, and fast storm motions
over the Columbia Basin into the Northern Rockies will promote
isolated wet/dry thunderstorms. In addition, preceding days of hot
and dry conditions has allowed fuels to approach critical
thresholds, making the environment increasingly receptive to new
ignitions. As upper level flow strengthens and impinges upon the
Northwest, tightening surface pressure gradients along the Cascades
will promote very gusty winds amid a dry boundary layer. Elevated
highlights have been maintained where RH values will decline to less
than 20% as winds increase to 15-20 mph (localized gusts up to 35
mph in terrain-favored areas). Greater concern for new ignitions and
impacts to ongoing fires exist where the Elevated and Isolated Dry
Thunderstorm highlights overlap.
...Southern Plains...
A mid-level shortwave trough will track across the High Plains this
afternoon as a surface low emerges over the Oklahoma/Texas
Panhandles. At peak heating, 15-20% RH will combine with
southwesterly winds of 10-15 mph atop a mixed fuelscape. Pockets of
cured grasses and ERCs approaching the 80-90th percentile will
promote locally elevated fire concerns.
..Elizalde-Garcia.. 07/23/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1225 AM CDT Thu Jul 23 2026
Valid 241200Z - 251200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHEASTERN
CALIFORNIA...NORTHWESTERN NEVADA...AND SOUTH-CENTRAL/SOUTHEASTERN
OREGON...
...Synopsis...
Upper-level ridging will begin to transition towards the central
U.S. as eastern Pacific troughing approaches the Pacific Northwest.
Meanwhile, troughing will persist across the eastern U.S. with
several embedded shortwaves providing unsettled conditions in the
Midwest and portions of the Southeast.
Enhanced southwesterly flow will overspread the Pacific Northwest,
Northern Rockies, and the Montana Plains on Day 2/Friday, bringing
hot, dry, and windy conditions to a mostly dry fuelscape. With
preceding days of mixed wet/dry thunderstorms and abundant lightning
being followed by such meteorological conditions, holdover ignitions
are likely to emerge. Daytime RH values of less than 20% are
expected to combine with southwest-westerly sustained winds of 15-20
mph, warranting Elevated highlights. While some pockets of heavier
rainfall from prior days thunderstorms may alleviate localized fuel
concerns, the expansive environment is approaching, or has already
reached, critical fuel thresholds. A Critical risk area was
introduced across northeastern California, northwestern Nevada, and
south-central/southeastern Oregon where 15-25 mph southwesterly
winds and less than 15% RH will overlap 80-90th percentile ERCs.
Critical winds/RH are likely to develop across portions of
north-central and northeast Montana as well, but these conditions
will likely act as more of a curing event.
..Elizalde-Garcia.. 07/23/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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