RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sun Sep 14 07:40:02 UTC 2025.
No Mesoscale Discussions are in effect as of Sun Sep 14 07:40:02 UTC 2025.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Sun Sep 14 2025
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
NORTHERN AND CENTRAL GREAT PLAINS...
...SUMMARY...
Isolated severe thunderstorms are possible across a broad portion of
the Great Plains this afternoon to early evening. A more
concentrated threat for a couple tornadoes is evident over parts of
the Dakotas and for large hail along the Nebraska-Kansas border.
...Dakotas...
The nose of a diurnally strengthening low-level jet will advance
north across the Dakotas today. Deeper boundary-layer mixing will
occur within the convective-free portion of the low-level jet. An
arc of seasonably rich boundary-layer moisture, characterized by mid
60s to low 70s surface dew points, will lie to its north from
eastern ND to the Lower OH Valley along the diurnally sharpening
surface warm front. A mesoscale corridor of enhanced low-level SRH
coincident with this rich moisture should pivot northward from
north-central SD through parts of central/eastern ND this afternoon.
CAM guidance varies in the degree of convective development, which
will be modulated by adequate insolation downstream of morning
convection from central NE to western SD. A few rotating cells seems
plausible, with the primary hazard being tornado. Weak mid-level
lapse rates should temper the overall threat though and storm
intensity will wane as the boundary layer cools after sunset.
...Central Great Plains...
A confined plume of steep mid-level lapse rates will accompany the
southeast flank of the consolidating negative-tilt trough ejecting
north-northeast from the central High Plains. In the wake of
persistent morning convection, boundary-layer heating should become
pronounced from the TX Panhandle across western KS. This should
support a corridor of ample buoyancy where low to mid-level lapse
rates are steep. This corridor should be offset west of the confined
belt of stronger mid-level flow. Nevertheless, with scattered to
widespread storms, some of these should contain transient supercell
to mainly multicell structures. Scattered large hail and isolated
severe gusts should be the primary threats in this regime during the
late afternoon to early evening.
...Southern High Plains...
Scattered thunderstorm development is expected during the afternoon,
as rapid destabilization occurs in the wake of morning convection
progressing east. Modest mid-level westerlies, south of the
negative-tilt shortwave trough advancing north of the central High
Plains, should provide adequate deep-layer shear for transient
supercell and multicell structures. But weak mid-level lapse rates,
amid relatively warm mid-level temperatures, should temper updraft
vigor. This should support a likely isolated severe threat.
...Mid-South/Mid-MS Valley...
Ample buoyancy along and southwest of the synoptic warm front should
aid in a few strong gusts and small hail with scattered late
afternoon storms. Rather weak deep-layer shear within the mid-level
ridge indicates a predominant pulse mode, supporting a negligible
threat for organized severe.
..Grams/Squitieri.. 09/14/2025
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1206 AM CDT Sun Sep 14 2025
Valid 151200Z - 161200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorm potential appears generally low on
Monday.
...Discussion...
A pair of upper shortwave troughs will be located over the northern
Rockies and the Upper Midwest on Monday. The upper trough oriented
over the eastern Dakotas/MN will lift north into Canada through
early evening, while the northern Rockies upper trough meanders
slowly eastward, developing an upper cyclone over MT/WY. Another
upper cyclone is expected to persist over the Carolinas, while upper
riding builds across the Pacific coast states and Midwest.
At the surface, seasonal boundary layer moisture will be in place
across the southern and central Plains into the MS Valley, resulting
in pockets of weak to moderate instability. Any stronger instability
is likely to remain displaced from stronger vertical shear, which
will be quickly shifting northward from the Upper Midwest into
Canada with the departing upper shortwave trough. Isolated to
scattered thunderstorms will still be possible within a corridor of
60s F dewpoints and moderate instability from the Ozarks vicinity
into MN within a low-level warm advection regime. However, severe
potential will largely remain low given limited shear and forcing
for ascent. The exception could be a strong storm or two in
MN/western WI where effective shear magnitudes around 20-25 kt and
MLCAPE up to 2000 J/kg will be in place. However, given the upper
trough will be departing the region, subsidence may limit storm
coverage/longevity across the area.
Additional scattered storms are possible across parts of the
northern/central High Plains ahead of a weak surface front/trough.
Steep midlevel lapse rates will be in place, and strong heating will
aid in steepened low-level lapse rates amid a deeply mixed boundary
layer. Severe potential should remain limited given weak
shear/instability, but inverted-v sub-cloud thermodynamic profiles
could foster locally gusty winds with any showers/thunderstorms.
..Leitman.. 09/14/2025
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0150 AM CDT Sun Sep 14 2025
Valid 161200Z - 171200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL PLAINS...
...SUMMARY...
Isolated strong to severe thunderstorms are possible on Tuesday
across portions of the central Plains.
...Central Plains...
A positive-tilt upper shortwave trough is forecast to develop
eastward from MT/WY into the northern/central Plains on Tuesday.
Deep-layer flow is expected to remain modest, though 30-40 kt of
southwesterly flow is forecast at 500 mb ahead of the trough across
the NE vicinity. At the surface, a weak cold front is expected to
develop southeast across the Upper Midwest and central Plains. A
seasonally moist airmass, with dewpoints from the upper 50s to mid
60s F will be in place ahead of the front, supporting moderate
instability from NE/KS into MN/WI.
Stronger forcing for ascent may not occur until after peak heating
as the trough ejects slowly east. Additionally, forecast soundings
indicate weak capping may persist near the surface boundary. If
storms do develop prior to 00z, deep-layer flow parallel to the
surface boundary may result in storms becoming undercut by the
front. Nevertheless, where favorable/sufficient effective shear
magnitudes overlap with stronger instability/steep midlevel lapse
rates, a few stronger storms could develop. This may be most likely
across parts of NE and vicinity where the cold front intersects a
weak low/surface trough, increasing low-level convergence along the
boundary. Even if storms are somewhat elevated, isolated hail and
gusty winds would be possible. While timing and coverage remain
uncertain, the overall parameter space suggests a couple of
marginally severe storms will be possible.
..Leitman.. 09/14/2025
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0237 AM CDT Sun Sep 14 2025
Valid 171200Z - 221200Z
...DISCUSSION...
Organized severe thunderstorm potential appears low during the Day
4-8/Wed-Sun period. Medium range guidance is in fairly good
agreement that the upper shortwave trough over the northern/central
Plains Day 4 will develop an upper low as it meanders slowly east
toward the Mid/Upper MS Valley and the upper Great Lakes through
most of the forecast period. Some modest west/southwesterly
mid/upper flow ahead of the trough, in conjunction with a seasonally
moist boundary layer ahead of a southeastward-drifting cold front
could support sporadic strong storms across parts of the central
U.S. from the Ozarks to the Upper MS Valley mid to late in the week.
However, vertical shear is expected to remain poor, and the
slow-moving nature of the upper low and weakening surface front with
time/eastward extent, will generally be unfavorable for a more
robust severe risk.
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0147 AM CDT Sun Sep 14 2025
Valid 141200Z - 151200Z
...NO CRITICAL AREAS...
...Synopsis...
A mid-level trough will traverse the Pacific Northwest and northern
Rockies as another upper trough ejects into the Plains today.
Modestly dry and breezy conditions will result across portions of
the Great Basin. However, the marginally favorable low-level RH, and
fuels that are poorly receptive to wildfire spread, suggest that the
chances for significant wildfire ignition and growth are relatively
low. The lifting of a buoyant airmass ahead of the western upper
trough will support scattered thunderstorm development across
portions of the Pacific Northwest into the northern Rockies.
However, fuels do not appear dry enough for robust lightning
ignitions to warrant any dry thunderstorm highlights.
..Squitieri.. 09/14/2025
...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
0147 AM CDT Sun Sep 14 2025
Valid 151200Z - 161200Z
...NO CRITICAL AREAS...
...Synopsis...
A mid-level trough will meander over the northern Rockies, promoting
mainly cool and mild conditions across the northwest quadrant of the
U.S. tomorrow (Monday). Scattered thunderstorms will be possible
across portions of the northern Rockies into the northern High
Plains, but the associated rainfall may serve to further dampen
fuels. As such, no major wildfire-spread conditions are expected
across the CONUS on Monday.
..Squitieri.. 09/14/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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