Day 4-8 Outlook

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0217 AM CDT Wed Mar 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
An upper ridge is forecast to break down across the Southwest late
Saturday/D4 into Sunday/D5, with a weak wave embedded in the
northwesterly flow regime aloft. During the same time, a stronger
but low-amplitude feature will move rapidly east/southeast along the
Canadian border, across the Great Lakes and into the Northeast.

In association with the northern/Great Lakes disturbance, a cold
front is forecast to push south into the Plains on Sunday/D5,
extending into the OH Valley by late in the day. This front will
interact with marginal moisture return across the Mid MS/OH Valleys,
and continue into the Southeast on Monday/D6. This front is forecast
to be roughly parallel to the upper flow, and would likely undercut
thunderstorms that develop along it. MUCAPE on the order of 500-1000
J/kg seems reasonable, which will support marginal severe at best.

For the latter days of the period, the forecast becomes less
predictable, however, models on a run to run basis appear to be
trending toward higher heights/possible ridging over the Southwest,
with little to no threat of severe storms.

No watches are valid as of Wed Mar 18 07:21:01 UTC 2026.

No Mesoscale Discussions are in effect as of Wed Mar 18 07:21:01 UTC 2026.

SPC Day 2 Fire Weather Outlook

Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0204 AM CDT Wed Mar 18 2026

Valid 191200Z - 201200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN WYOMING...

...Synopsis...
Upper-level ridging will remain in place across the Southwest for
D2/Thursday, with strong northwesterly upper-level flow persisting
across the northern Rockies and central CONUS. This will support a
continued downslope regime across the central High Plains and
western Wyoming Basin, with elevated to critical fire weather
conditions expected amid strong west-northwest surface winds and
very low RH values.

...Portions of the central High Plains into the western Wyoming
Basin...
The synoptic-scale pattern will remain relatively consistent from
today into D2/Thursday, with anomalously strong upper-level ridging
persisting across the Southwest and strong northwesterly flow in
place across the central Rockies. At the surface, high pressure
across the Intermountain West will couple with surface low pressure
shifting southeastward across southern Canada to support reduced RH
values of 10-15% and west-northwesterly downslope winds of 20-25
mph. With persistent dry/windy conditions continuing to aid in the
maintenance of receptive fuels, this is expected to yield critical
fire weather conditions across much of southeastern Wyoming. Current
guidance indicates mid-level flow will weaken slightly from D1 into
D2, but deep boundary layer mixing may also support wind gusts of
30-35 mph across much of this area.

Elevated fire weather concerns are also expected across adjacent
regions, including much of southwestern Wyoming, portions of extreme
northern Colorado, the western Nebraska Panhandle, extreme
southwestern South Dakota, and extreme northeastern Utah, where
sustained westerly surface winds of 15-20 mph are forecast to
overlap reduced RH of 10-15%. Marginal fuel receptiveness and lower
confidence in higher sustained winds are expected to limit the
northern extent of widespread elevated fire weather concerns at this
time; however, this area will be monitored for potential expansion
as fuels continue to dry given the persistent pattern and resultant
anomalous temperatures expected over much of the region.

..Chalmers.. 03/18/2026

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

SPC Day 1 Fire Weather Outlook

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0116 AM CDT Wed Mar 18 2026

Valid 181200Z - 191200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHEASTERN
WYOMING...EXTREME WESTERN NEBRASKA...AND EXTREME NORTHERN
COLORADO...

...Synopsis...
A northwesterly upper-level flow regime will become established over
the northern Rockies and central CONUS today downstream of an
anomalously strong upper-level ridge centered over the Southwest.
This setup will favor strong downslope flow in the lee of the
central Rockies, with westerly to northwesterly surface winds and
very low RH values supporting elevated to critical fire weather
conditions across portions of the central High Plains.

...Portions of the central High Plains...
Northwesterly upper-level flow will strengthen across the northern
Rockies and central CONUS today downstream of an anomalously strong
upper-level ridge centered over the Southwest. With stronger
mid-level flow displaced toward the northern Rockies, surface lee
troughing will become most pronounced across central Montana to
eastern Wyoming this morning into this afternoon. When coupled with
surface high pressure established across the Intermountain West,
this will support strong downslope flow in the lee of the central
Rockies, with forecast guidance indicating sustained westerly to
northwesterly surface winds of 20-25 mph overlapping very low RH of
10-15%. With antecedent drought conditions and preceding dry/windy
conditions maintaining dry fuels and helping cure fine fuels in
areas that recently received precipitation, this will support
critical fire weather conditions across portions of southeastern
Wyoming, the western Nebraska Panhandle, and extreme northern
Colorado. The strongest winds are forecast near and east of the
leeward slopes of the Laramie Range, where deep boundary layer
mixing coupled with strong mid-level flow will also support the
potential for wind gusts of 30-35 mph. Latest high resolution
guidance also indicates slightly enhanced potential for critical
conditions within the North Platte River Valley from eastern Wyoming
into western Nebraska where topographical influences may locally
enhance downsloping effects. 

Elsewhere across the central High Plains, westerly to northwesterly
downslope winds of 15-25 mph will overlap reduced RH values of
15-25% to support elevated fire weather conditions across much of
eastern Wyoming, extreme southwestern South Dakota, the Nebraska
Panhandle, northeastern Colorado, and extreme northwestern Kansas.
Marginal fuel receptiveness is expected to limit widespread elevated
fire weather concerns for areas farther north and west at this time.

..Chalmers.. 03/18/2026

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

SPC 0730Z Day 3 Outlook

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
1229 AM CDT Wed Mar 18 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
A low chance of a few thunderstorms may develop near the Upper Ohio
Valley and vicinity on Friday.

...Synopsis and Discussion...
An upper ridge will hold over the Southwest on Friday, with strong
northwest flow aloft along the Canadian border. A low-amplitude
upper wave will intensify into northern MN and toward the upper
Great Lakes late in the day and overnight, with a weak surface low
also traversing the Great Lakes. A cold front will extend from
southwest Ontario into IL and MO by 00Z, and southerly winds ahead
of it will bring a plume of low to mid 50s F dewpoints northward
across TN/KY/IN/OH during the afternoon.

Despite the low-level moistening, instability will likely be
minimal. However, weak elevated instability may develop within the
warm advection zone roughly from OH into PA, with a low chance of
isolated thunder.

..Jewell.. 03/18/2026

SPC 0600Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1229 AM CDT Wed Mar 18 2026

Valid 191200Z - 201200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms are unlikely on Thursday.

...Synopsis...
An upper high will be centered over Arizona on Thursday, with a
large-scale upper ridge from CA into the southern High Plains. East
of there, northwest flow aloft will be maintained over the central
states, as elongated upper troughing persists along the East Coast.

At the surface, high pressure will be prevalent over much of the
CONUS, with centers over the Great Basin and from the Mid Atlantic
into the northern Gulf of America. Given this dry and stable
pattern, thunderstorms are not expected.

..Jewell.. 03/18/2026

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1256 AM CDT Wed Mar 18 2026

Valid 181200Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms will be possible today across far south
Florida.

...DISCUSSION...
An upper-level trough will move across the eastern U.S. today, as
northwest mid-level flow remains over much of the rest of the
nation. At the surface, high pressure will move eastward to the
Eastern Seaboard, as a dry airmass stays in place over most of the
continental U.S. The only chance for thunderstorms today will be
over far south Florida, where enough instability will be in place
for isolated thunderstorm development. No severe threat is forecast
over the U.S. today and tonight.

..Broyles/Chalmers.. 03/18/2026