SPC Day 1 Fire Weather Outlook

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1146 AM CDT Mon Sep 15 2025

Valid 151700Z - 161200Z

...NO CRITICAL AREAS...

...17z Update...
Easterly flow is expected to develop over portions of the western
Columbia Basin and Cascade ranges late tonight through D2/Tuesday.
With gusts of 20-25 mph possible at ridge-top level and through
gaps, some dry and breezy conditions are possible. However, the
marginal RH values and recent precipitation should keep fuels
tempered, with any fire-weather concerns expected to be brief and
localized. Otherwise, see the prior outlook for more information.

..Lyons.. 09/15/2025

.PREV DISCUSSION... /ISSUED 0142 AM CDT Mon Sep 15 2025/

...Synopsis...
A mid-level trough will become situated over the northern Rockies
today, promoting mainly quiescent fire weather conditions across the
western CONUS. Ahead of the upper trough, thunderstorms may develop
over the northern Rockies into the northern High Plains. Some of
these storms may be fast moving and high based, accompanied by
erratic wind gusts. Nonetheless, fuels are at best marginally
receptive to wildfire spread, with no fire weather highlights
introduced this outlook.

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

No watches are valid as of Mon Sep 15 16:49:02 UTC 2025.

No Mesoscale Discussions are in effect as of Mon Sep 15 16:49:02 UTC 2025.

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1132 AM CDT Mon Sep 15 2025

Valid 151630Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN HIGH PLAINS...NORTHERN MINNESOTA...OZARKS/MID-SOUTH...AND
COASTAL NC/VA...

...SUMMARY...
Isolated severe wind gusts are possible across Wyoming into western
South Dakota this afternoon to early evening, as well as portions of
the Ozarks/Mid-South. Isolated severe hail and damaging winds are
possible across far northern Minnesota in the early to
mid-afternoon. A brief tornado is possible in the northeast North
Carolina vicinity in the early morning Tuesday.

...Wyoming to Black Hills vicinity...
A shortwave trough over western Idaho will move east across
Wyoming/western South Dakota during the day, as several embedded
vorticity maxima contribute regions of enhanced ascent. Steep
mid-level lapse rates of 8-9 deg C/km, combined with diurnal
heating, will result in MLCAPE of a few hundred J/kg across much of
the area. Despite weak buoyancy, the favorably-timed ascent will
contribute to thunderstorm development/intensification this
afternoon as storms approach northeast Wyoming/western South Dakota.
Some hail could occur, and a deep and well-mixed boundary layer will
lead to high-based convection capable of isolated strong/damaging
gusts through early evening, with intensities diminishing thereafter
as nocturnal cooling commences.

...Northeast North Carolina/southeast Virginia...
A surface low southeast of Cape Hatteras is forecast to move towards
the North Carolina coast through 12z Tuesday, with a belt of
stronger low-level flow developing north/northwest of the low.
Variability remains regarding the forecast location of the low and
strength of low-level winds, however a conditional risk for a
tornado would exist late tonight through early Tuesday morning with
stronger convective elements, should sufficient low-level hodograph
curvature develop as high theta-e air is advected west.

...Far northern Minnesota...
Thunderstorm development is expected this afternoon within a
northwest-southeast oriented arc from southeast Manitoba across
northeast Ontario as a shortwave trough becomes increasingly
negatively tilted while lifting northeast. Although development
south of the international border is uncertain, some global guidance
(and a convection-allowing model or two) suggest isolated
development is possible. Moderate buoyancy and effective shear of
35-40 kt over far northern Minnesota suggest a conditional risk for
severe wind/hail would exist if/where storm development occurs.

...Missouri/Mid-South..
Near and west/southwest of a residual front, a few strong/locally
damaging wind gusts will be possible again this afternoon with
pulse-type storms within a weakly-sheared but strongly unstable
(MLCAPE of 2500-3000 J/kg) thermodynamic environment.

..Guyer/Thornton.. 09/15/2025

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0742 AM CDT Mon Sep 15 2025

Valid 151300Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM WYOMING
INTO WESTERN SOUTH DAKOTA...OVER FAR NORTHERN MINNESOTA...AND
NORTHEAST NORTH CAROLINA...

...SUMMARY...
Isolated severe gusts are possible across Wyoming into western South
Dakota this afternoon to early evening. Isolated severe hail and
damaging wind are possible across far northern Minnesota in the
early to mid-afternoon. A brief tornado is possible in the northeast
North Carolina vicinity in the early morning Tuesday.

...WY to western SD...
A shortwave trough over western ID will move east across WY/western
SD during the day, as several embedded vorticity maxima contribute
regions of enhanced ascent. Steep mid-level lapse rates of 8-9 deg
C/km, combined with diurnal heating, will result in MLCAPE of a few
hundred J/kg across much of the area. Despite weak buoyancy, the
favorably-timed ascent will contribute to thunderstorm
development/intensification this afternoon as storms approach
northeast WY/western SD. A deep and well-mixed boundary layer will
lead to high-based convection capable of isolated strong/damaging
gusts through early evening, with intensities diminishing thereafter
as nocturnal cooling commences.  

...Northeast NC/southeast VA vicinity...
A surface low southeast of Cape Hatteras is forecast to move towards
the NC coast through 12z Tuesday, with a belt of stronger low-level
flow developing north/northwest of the low. Variability remains
regarding the forecast location of the low and strength of low-level
winds, however a conditional risk for a tornado would exist early
Tuesday morning with stronger convective elements, should sufficient
low-level hodograph curvature develop, as high theta-e air is
advected west across the northeast NC/southeast VA vicinity.

...Far northern MN...
Thunderstorm development is expected this afternoon within a
northwest-southeast oriented arc from southeast Manitoba across
northeast Ontario as a shortwave trough becomes increasingly
negatively tilted while lifting northeast. Although development
south of the international border is uncertain, some CAM guidance
suggest isolated development is possible. Moderate buoyancy and
effective shear of 35-40 kts over far northern MN suggests a
conditional risk for severe wind/hail would exist should storm
development occur in this area.

...MO/AR vicinity...
A few strong gusts will be possible again today with pulse-type
storms within a weakly-sheared but strongly unstable (MLCAPE of
2500-3000 J/kg) environment.

..Bunting/Broyles.. 09/15/2025