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U.S. Day 1 Fire Weather Outlook
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 111644
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1144 AM CDT Mon May 11 2026
Valid 111700Z - 121200Z
...CRITICAL FIRE WEATHER AREA FOR PARTS OF EASTERN MONTANA INTO
WEST-CENTRAL NORTH DAKOTA...
...Northern and Central Plains...
A deepening lee trough across far eastern MT under a 60-70 knot
mid-level jet will contribute to fire weather concerns across
portions of the northern and central Plains through today. Stronger
south winds of 15-20 mph ahead of the eastward moving surface trough
are occurring over the Dakotas, with latest model guidance
suggesting this steady southerly flow being maintained through the
day. RH is trending lower with potential for broader instances of
20-25% by peak afternoon heating, particularly across eastern ND and
the Red River Valley of the North. Elevated Highlights have been
extended eastward to encompass all of ND and portions of western MN
today.
Farther west in the wake of the departing trough, dry and breezy
conditions including west/northwest winds 20-25 mph combined with
afternoon RH of 15-25% and dry fuels will support Critical fire
weather conditions for portions of northeastern MT into west-central
ND. A slight eastward expansion of Critical Highlights further into
ND was made based on latest surface observation and forecast
guidance trends.
..Williams.. 05/11/2026
.PREV DISCUSSION... /ISSUED 0151 AM CDT Mon May 11 2026/
...Synopsis...
Along the northern periphery of a large-scale ridge centered over
the West, a robust midlevel trough and accompanying 70-kt westerly
jet streak will advance eastward across MT and ND during peak
heating. In the low-levels, a lee trough will extend southward along
the northern/central Plains, before being overtaken by a cold front
during the evening.
...Northern and Central Plains...
Within the base of the midlevel trough, strong deep-layer westerly
flow will overspread the northern High Plains during the day. Here,
downslope flow trajectories and diurnal heating will result in a
deeply mixed boundary layer along/west of the lee trough --
characterized by surface temperatures in the middle/upper 70s and
20-25 percent RH. Despite the somewhat marginal RH reductions,
downward transport of the high-momentum flow and a tight pressure
gradient will contribute to 20-25 mph sustained west-northwesterly
surface winds (with gusts upwards of 35 mph). The greatest overlap
of these strong/gusty winds and low RH atop receptive fuels is
expected over parts of eastern MT into west-central ND -- where
Critical highlights are in place. A north-northwesterly surface wind
shift will accompany the frontal passage during the evening hours,
though substantial post-frontal RH recovery is expected.
Farther south along the lee trough into the central Plains, more
substantial downslope warming/drying will yield temperatures in the
lower/middle 80s and 15-20 percent RH. These warm/dry conditions
combined with around 15 mph sustained west-southwesterly surface
winds will yield elevated to locally critical fire-weather
conditions, given critically dry fuels here as well.
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U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 111941
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0241 PM CDT Mon May 11 2026
Valid 121200Z - 131200Z
A dry, post-frontal northwest flow regime is still expected to bring
a broad fire weather threat to portions of the northern/central
Plains and Upper Midwest on Day 2/Tuesday. A swath of stronger
sustained northwest winds between 15 and 25 mph will impact the
eastern Dakotas into southwestern MN. However, this corridor of
stronger winds will be displaced to the east of a warmer, drier
boundary layer across the northern and central High Plains where
afternoon RH reductions below 20% will be more common. Nonetheless,
the breezy northwest winds and very dry fuels (ERC values in the
95-99th percentile) should support an elevated fire weather concern
for much of the Dakotas, southwest MN into northeastern NE and
northwestern IA. Additionally, some green up of fuels could mitigate
the otherwise Critical fire weather threat across eastern
NE/northwestern IA.
..Williams.. 05/11/2026
.PREV DISCUSSION... /ISSUED 0151 AM CDT Mon May 11 2026/
...Synopsis...
On the backside of a robust midlevel trough and attendant surface
low moving eastward from the northern Plains into the upper Midwest
and eventually the Great Lakes, strong deep-layer northwesterly flow
will overspread a well-mixed post-frontal air mass over the
upper/middle MO Valley during the day. While RH reductions will be
modest in the post-frontal air mass (around 25-30 percent), 20-25
mph sustained northwesterly surface winds (with higher gusts) will
compensate and support elevated to locally critical fire-weather
conditions -- given dry/receptive fuels. If guidance trends any
lower with RH reductions, a targeted Critical area could eventually
be warranted.
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 112205
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0505 PM CDT Mon May 11 2026
Valid 131200Z - 191200Z
...Synopsis...
A potent mid-level trough will move into the northwestern U.S. on
Day 3/Wednesday while an amplifying upper trough and corresponding
surface low move into the Northeast. A deep lee surface trough
evolves across the northern and central High Plains in response to a
mid-level wave ejecting into the northern Plains on Wednesday,
bringing enhanced downslope westerly flow to the central and
southern High Plains on Day 4/Thursday. Fire weather concerns
continue across portions of the Northern Plains Day 5/Friday as dry,
northwest flow in the wake of a cold front impacts the region. The
active wave pattern across the northern CONUS with deeper boundary
layer moisture in place could support more widespread and much
needed rainfall across the Upper Midwest beginning Day 5/Friday and
over the weekend.
...Day 3-4/Wednesday-Thursday...
...Eastern Great Basin into Upper/Lower Colorado River Basin...
A robust mid-level wave will push through the Pacific Northwest Day
3/Wednesday. Stronger southwest flow aloft ahead of the trough and
resultant deepening surface troughing across the northern Great
Basin is expected to bring fire weather concerns to considerable
portions of the Intermountain West. Southwest winds of 15-25 mph
amid low RH and drying fuels under successive days of abnormally
high temperatures should promote a fairly broad fire weather threat
across the eastern Great Basin, northern AZ and CO Plateau.
Increasing mid-level Pacific moisture across the Intermountain West,
arrival of the upper trough into the western U.S. and daytime
instability should allow for high-based convection along higher
terrain of the Upper CO River Basin, Four Corners and into western
NM where more receptive fuels reside. Both critical probability
areas for impactful dry and breezy conditions and dry thunderstorms
were expanded across this region.
...Upper Snake River Plain and Southwest Montana...
Southwest winds of 20-25 mph across eastern ID, with terrain
enhanced winds closer 30-45 mph (with higher gusts) in southwest MT
are expected Day 3/Wednesday as the sharp upper trough and
associated mid-level jet shifts overhead. Dry boundary layer
conditions amid a drying fuelscape combined with the stronger
southwest flow will enhance fire weather concerns across the Upper
Snake River Plain and southwest MT, where 40% critical probabilities
have been introduced.
...Northern Montana...
Fuels remain quite receptive across northern MT where delayed green
up has been noted. A rapidly evolving lee low in the southern
Canadian Prairies will promote a dry return flow pattern across the
northern High Plains where 40% critical probabilities were
maintained. Fast moving, high based showers and thunderstorms are
expected across central and northern MT Wednesday afternoon as broad
ascent materializes ahead of the pronounced short wave trough across
the Pacific Northwest. Limited precipitation with fast moving
thunderstorms could bring a few ignitions to northern MT where fuels
are more receptive, where a 10% dry thunderstorm probability area
was warranted. Strong westerly winds behind a cold front could
impact holdover ignitions on Day 4/Thursday where 40% critical
probabilities were introduced across southeastern MT into portions
of western ND/SD.
...Day 5/Friday - Northern Plains...
Fire weather concerns may linger across portions of the Northern
Plains on Day 5/Friday with dry, post-frontal west/northwest flow in
place, but forecast uncertainty remains precluding introduction of
critical probabilities at this time.
..Williams.. 05/11/2026
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