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U.S. & Canada 00-UTC 48 Hour Surface Smoke Forecast
Map is in operation from early April through October 31
U.S. Day 1 Fire Weather Outlook
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 241614
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1114 AM CDT Sun May 24 2026
Valid 241700Z - 251200Z
...NO CRITICAL AREAS...
The previous forecast remains on track with no changes needed for
this outlook update. See previous discussion below.
..Williams.. 05/24/2026
.PREV DISCUSSION... /ISSUED 0158 AM CDT Sun May 24 2026/
...Synopsis...
Upper-level troughing will transition eastward across the northern
Great Lakes today, with weak troughing also in place across the
southern California and the southern Plains. Simultaneously,
upper-level ridging will remain over the East Coast and much of the
High Plains. At the surface, a frontal system will extend from the
southern Great Plains northeastward into the Midwest and
Mid-Atlantic, with multiple mid-level perturbations bringing chances
for wetting rainfall to much of the South and the eastern US.
Similar to Saturday, warm temperatures under subtle ridging will
promote RH reductions to 10-20% across much of the West, but the
lack of a strong surface pressure gradient will largely limit
sustained wind speeds. This will preclude widespread fire weather
concerns. Locally elevated conditions may still be possible in
favored terrain/gap areas, however.
...North-central Montana...
Modest westerly mid-level flow will promote deepening lee troughing
across the southern Canadian Prairies and the northern High Plains
today, with dry and breezy conditions expected across northern
Montana. Sustained westerly surface winds of 15-20 mph and minimum
RH values as low as 15% will promote localized elevated fire weather
concerns, mainly for areas where green up has been delayed by
drought.
...Northern Great Basin into Southern Idaho...
A plume of modest mid/upper-level subtropical moisture will extend
from the Sierra Nevada eastward into southern Idaho, southern
Wyoming, and the northern Colorado Rockies today. Diurnal heating
will promote weak buoyancy within this moisture corridor, which will
subsequently support isolated high-based convection this afternoon.
Fuels and ongoing green up will continue to limit the potential for
dry lightning ignitions. Thus, dry thunderstorm highlights continue
to be withheld.
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U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 241919
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0219 PM CDT Sun May 24 2026
Valid 251200Z - 261200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHWESTERN NEVADA
INTO SOUTHEASTERN OREGON...
...Great Basin...
Minor adjustments to the Critical highlights were made based on
latest model guidance. Forecast remains largely on track with strong
southwesterly pre-frontal winds of 15-25 mph affecting northwest
portions of the Great Basin as a robust upper trough enters the
Pacific Northwest. The breezy southwest winds combined with RH
reductions as low as 15% and cured/drying lower elevation fuels will
result in a critical fire weather threat for southeastern OR and
northwestern NV on Monday.
...Southwest...
A mid/upper trough and associated northward moisture transport
shifts into the Southwest Monday, bringing isolated to widely
scattered thunderstorms over receptive fuels across much of the
northeastern AZ into far southeastern AZ and adjacent NM.
Thunderstorms will initially be high-based, with a dry boundary
layer supporting evaporation of nascent rain cores. Latest forecast
guidance suggests more robust boundary layer moistening and
prolonged convective event across west-central NM and far
east-central AZ where wetting rains are more likely, with local
accumulations of 0.50" possible. Isolated Dry Thunderstorm
Highlights have been removed based on these higher expected rainfall
amounts. High-based thunderstorm development should still be primary
convective mode along and south of the Mogollon Rim and fringes of
the deeper subtropical moisture across the lower elevation areas of
southeastern AZ/southwestern NM, where isolated Dry Thunderstorm
Highlights remain.
..Williams.. 05/24/2026
.PREV DISCUSSION... /ISSUED 0200 AM CDT Sun May 24 2026/
...Synopsis...
A potent mid-level trough will move onshore of the Pacific Northwest
on D2/Monday as a second mid-level trough transitions northeastward
across northern New England. Weak troughing will also persist across
the lower Mississippi Valley/southern Plains and across the
Southwest. Meanwhile, upper-level ridging will remain in place
across the Southeast and central/northern Plains. A surface low will
track offshore of New England, with a trailing cold front
progressing through the Mid-Atlantic before extending southwestward
into the southern Plains. A cold front will also begin to advance
eastward across the Pacific Northwest in tandem with a deepening
surface low.
...Great Basin...
A strengthening surface pressure gradient ahead of the approaching
cold front will promote sustained southwesterly surface winds of
20-25 mph, with above normal temperatures and minimum RH values of
10-15% also expected. Recent fire activity suggests that fuels are
becoming more receptive to wildfire spread across this region. Thus,
these conditions are expected to support a corridor of critical fire
weather concerns from northwestern Nevada into southeastern Oregon
Monday afternoon. Sustained southwesterly winds of 15-25 mph
overlapping reduced RH of 15-25% will also promote elevated fire
weather conditions across adjacent areas of the Great Basin.
...Southwest...
A mid-level shortwave trough and accompanying subtropical moisture
plume will contribute to weak buoyancy atop well-mixed boundary
layer profiles. This is expected to support widely scattered,
high-based convection across much of northeastern Arizona and
western New Mexico Monday afternoon. PWAT values ranging from
0.4-0.7" (locally up to 1") and more marginal LCLs ranging from 2-3+
km AGL will likely favor a mix of wet and dry thunderstorms. Given
that fuels across the region remain quite dry (ERCs around the 90th
percentile), isolated lightning ignitions remain possible. Thus, the
10% dry thunderstorm probability has been maintained for this
update.
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 232203
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0503 PM CDT Sat May 23 2026
Valid 251200Z - 311200Z
...Synopsis...
An upper-level trough will dig into the western U.S. through much of
next week while a blocking ridge anchors over central CONUS. This
trough and associated increasing southwest flow will bring a fire
weather threat to portions of the Great Basin and Southwest through
at least Day 6/Thursday. A lower amplitude mid-level trough and
associated sub-tropical moisture entering the Southwest should
bring a dry thunderstorm threat to much of northeastern AZ and
western NM on Day 3/Monday, where fuels are more receptive to
ignitions.
...Day 3/Monday...
...Great Basin...
A deepening upper trough and robust mid-level jet enters the Pacific
Northwest Day 3/Monday, resulting in pronounced lee trough evolution
east of the Cascades. Stronger southwest winds of 15-25 mph are
expected across the northwestern Great Basin amid above normal
temperatures and low relative humidity. Recent fire activity
suggests fuels are becoming more receptive to wildfire spread. A 70%
critical probability area was introduced where corridor of enhanced
southwest winds and drier fuels are most likely to align.
...Southwest...
A mid-level shortwave with an accompanying subtropical moisture
plume will support high-based showers and thunderstorms for much of
northeastern AZ and western NM. Recent forecast guidance has trended
upward in precipitation amounts but fuels remain quite dry, with ERC
values hovering around the 90th percentile through this weekend.
Maintained 10% dry thunderstorm probability given receptive fuels
and ongoing fires on the landscape.
...Days 4-6/Tuesday-Thursday - Great Basin and Southwest...
As the upper trough becomes established across the western U.S.,
deep-layer southwesterly flow will sustain a fire weather threat for
portions of the Great Basin, Southwest and Four Corners regions
through midweek. However, the current 40% critical probability areas
may need to be adjusted in subsequent forecast updates if a more
expansive rainfall event unfolds Days 3-4/Monday-Tuesday.
..Williams.. 05/23/2026
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