561
FNUS28 KWNS 232135
FWDD38

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0433 PM CDT Sun Aug 23 2026

Valid 251200Z - 311200Z

...Synopsis...
An upper-level ridge extending northward from broad high pressure
across the Southwest will bring warmer and drier conditions to much
of the Northwest and Northern Rockies. Dry southwesterly flow aloft
and departure of deeper monsoon moisture will keep fire weather
concerns in the form of dry and breezy conditions for portions of
the Great Basin and Columbia Basin for the middle of the week,
reaching the central ID mountains by Day 5/Thursday as fuels dry.
The threat of dry thunderstorms returns to the northern Rockies Day
4/Wednesday with the arrival of an upper-level trough into the
Pacific Northwest. Diurnal showers/thunderstorms along higher
terrain will likely shift eastward, mainly along the Rockies by the
end of the week with another possible upper-level wave entering the
Pacific Northwest by the weekend, although forecast uncertainty
increases during this time frame.

...Northwest, Northern Great Basin and Northern Rockies...
A drier southwest flow pattern will bring a multi-day fire weather
threat back into portions of the northwestern U.S., with fire
weather concerns extending eastward into the central ID mountains
later this week as fuels recover from recent monsoon moisture. The
40 percent critical probabilities have generally been expanded for
Days 3-5/Tuesday-Thursday, with additional threat areas for both
Days 6-7/Friday-Saturday. West to southwest winds of 15-20 mph and
afternoon relative humidity between 15-20 percent will bring at
least daily elevated fire weather concerns to this region. Critical
fire weather conditions with winds of 20+ mph are likely but only in
localized areas, particularly from northeastern CA into far
northwestern NV and southeastern OR where afternoon relative
humidity reached 10 percent under more robust mid-level flow.
Enhanced onshore flow develops across the Pacific Northwest as the
next upper-level trough impacts the region midweek. This will
bolster downslope drying across the Columbia Basin where afternoon
relative humidity reductions of around 15 percent are possible. This
dry atmospheric and fuel environment, coupled with west/southwest
winds of 15-20 mph, will likely bring a fire weather threat for the
Columbia Basin both Wednesday and Thursday.

...Dry Thunderstorms...
The arrival of the next upper-level wave will bring additional
opportunities for afternoon showers and thunderstorms across the
northern Rockies on Day 4/Wednesday. The eastward shunting of deeper
monsoon moisture under a drier southwest flow regime and building
ridge over the northern Rockies on Day 3/Tuesday will likely
contribute to a drying boundary layer in advance of the next
mid/upper wave on Day 4/Wednesday. This should set the stage for at
least isolated high-based thunderstorm development over the northern
Rockies Wednesday afternoon where fuels will have undergone two days
of drying. Given the modest mid-level moisture with PWATs less than
0.8", widespread thunderstorm activity is not expected at this time
with a 10 percent probability area maintained.

..Williams.. 08/23/2026

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

$$