U.S. & Canada 12-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 170557
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Thu Jul 17 2025
Valid 171200Z - 181200Z
...Synopsis...
A shortwave trough will glance the Pacific Northwest bringing an
increase of westerly flow aloft across the Cascades into the Cascade
Gaps. As a result, areas of increased westerly downslope flow can be
expected along and just east of the Cascades in the Columbia River
Basin. Sustained winds 10-15 mph (locally higher in the Cascade
Gaps) overlap with afternoon relative humidity reductions to around
10-20 percent. An Elevated delineation was added with this outlook
to support this potential.
...Dry Thunderstorms...
A closed low off the coast of Baja California will bring moisture
northward across portions of the Southwest into the Great Basin. On
the fringe of this deeper moisture, isolated dry thunderstorm
potential will continue across portions of western Colorado into
western Wyoming, Utah, far southern Idaho and eastern Nevada. Here
precipitable water values drop to around 0.50" or less with more
limited coverage. Some mix of wet/dry thunderstorms will be possible
in central Utah and west-central Colorado but storm motions around
15-20 kts will likely yield little measurable precipitation.
..Thornton.. 07/17/2025
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U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 170558
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Thu Jul 17 2025
Valid 181200Z - 191200Z
...Synopsis...
A deeper trough will traverse the Pacific Northwest on D2/Friday
bringing more widespread Elevated conditions across the areas along
and east of the Cascades. Afternoon relative humidity around 10-20
percent will overlap sustained westerly winds at 10-15 mph (locally
higher). Some locally Critical conditions may persist for a couple
of hours where terrain enhancements favor locally stronger winds in
the Cascade Gaps.
...Dry Thunderstorms...
The western shortwave will bring forcing for ascent across portions
of northern Nevada into southern Idaho and eastern Wyoming. This
area remains on the periphery of deeper moisture across the
Southwest into the Great Basin. High based convection and very dry
boundary layer conditions will favor little to no measurable
precipitation with potential for new ignitions from lightning.
..Thornton.. 07/17/2025
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 162133
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0433 PM CDT Wed Jul 16 2025
Valid 181200Z - 241200Z
...Day 3/Friday...
A mid-level short wave entering into the Pacific Northwest will
bring increasing onshore flow and subsequent enhanced gap winds and
dry downslope flow into the Columbia Basin and central OR, where
expanding drought and dry fuels will promote wildfire spread.
Farther southeast, elevated monsoon moisture and daytime instability
over higher terrain along with some upper-level support from the
incoming Pacific Northwest trough will instigate isolated high-based
thunderstorms across portions of the northern Great Basin into
southern ID and western WY. Northward transport of deeper monsoon
moisture aided by a mid-level low over southern CA will continue to
bring isolated to scattered thunderstorms with higher precipitation
efficiency into the greater Four Corners region and southern Great
Basin, limiting threat of widespread lightning ignitions.
...Day 4-6/Saturday-Monday...
A deepening mid-level trough over the Pacific Northwest will usher
in a multi-day fire weather threat into the northwestern U.S. and
Great Basin regions over the weekend into early next week.
Increasingly dry southwesterly flow will push residual monsoon
moisture and thunderstorm threat primarily east of the Continental
Divide by Day 6/Monday. The dry and breezy conditions will migrate
southeastward starting with the Columbia basin and Snake River Plain
on Day 4/Saturday before encompassing much of the Great Basin,
northwestern UT and southeastern ID by Day 6/Monday. 40 percent
probabilities for critical fire weather conditions have been added
to the Great Basin region for Day 5-6/Sunday-Monday time frame.
Meanwhile, the deepening mid-level trough over the Pacific Northwest
will usher in cooler temperatures and higher humidity into the
region early next week, mitigating fire weather concerns.
...Day 7-8/Tuesday-Wednesday...
Uncertainty in timing regarding the lifting of the Pacific Northwest
trough, rebuilding of the ridge across the Western U.S. and
potential monsoon moisture surge into the Intermountain West limits
introduction of critical fire weather probabilities at this time.
..Williams.. 07/16/2025
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