188
FXUS65 KBOI 110346
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
846 PM MST Mon Nov 10 2025

.DISCUSSION...Periods of high clouds will move overhead tonight
as an upper level trough moves by to the north. Patchy fog will
develop in sheltered mountain valleys. On Tuesday, the axis of
a low amplitude upper level ridge will move overhead. The valley
inversion will be weakened by the departing trough, allowing
valley high temperatures to climb a couple of degrees from
today. Otherwise, winds will be light with mostly sunny skies as
the ridge moves overhead.

&&

.AVIATION...VFR under scattered high clouds. Patchy valley fog
overnight into Tuesday morning. Surface winds: variable less
than 10 kt overnight. Winds at 10kft MSL: W-SW 15-25 kt.

KBOI...VFR and mostly clear. Surface winds variable less than 7
kt overnight.

&&

.AIR STAGNATION...High pressure and subsidence aloft will keep
a temperature inversion in place on Tuesday with mixing heights
near or slightly below 2kft in the lower valleys. This will be
a slight improvement from Monday in the wake of a passing upper
trough that will cool temperatures aloft and weaken the
inversion. Surface winds will remain light into Tuesday, then
increase on Wednesday ahead of a system. A cold front Thursday
into Friday will bring precipitation, breezy winds, and
increased mixing. This will remove the valley inversion,
bringing an end to stagnant conditions.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...Mild and dry
conditions are expected today with high level clouds across the
area as a weak upper level trough moves across the Idaho
Panhandle. This trough should weaken the upper level ridge
significantly enough by this evening to scour out much of the
valley inversion that has been in place over the weekend.
Today`s highs will be around 10 degrees above normal, especially
in the mountains. The inversion will hold highs near normal
across the lowest elevations, where temperatures will be
slightly lower but still above normal. Tuesday should see warmer
temperatures in the valley with the weakened inversion.

Southwesterly flow aloft will increase on Wednesday as a deeper
trough approaches the West Coast. This should increase surface
winds in response, which will likely remove the inversion
entirely. This will help make Wednesday the warmest day for most
locations, as highs reach 10 to 15 degrees above normal, though
we will see periods of high clouds through the day. It will also
make for a breezy day, especially across the higher terrain of
southeast Oregon. A 15 to 30 percent chance of showers is
expected across southeast Oregon and the central Idaho mountains
late Wednesday night as the trough moves inland. Snow levels
will be 8000 to 9000 feet MSL as the precipitation begins.

LONG TERM...Thursday through Monday...The upper-level trough
that has been alluded to for quite some time will be moving into
the area starting Thursday. This initial system will bring an
associated cold front to increase wind gusts, particularly on
Thursday, and precipitation chances through most of the weekend.
The leading edge of the cold front will move across the region
Thursday bringing 60+% precipitation chances to most sites
through late Thursday/Friday morning. Snow levels will fall
west-to-east behind the cold front, going from around 8000 ft
MSL midday Thursday to 4500-5000 ft MSL by midday Friday. Lower
elevations see up to 0.20" with accumulations of 2 to 5 inches
above 6000 feet MSL. By Friday afternoon, the main upper-level
trough axis moves east, placing the area in northwesterly flow
aloft before shifting back to southwesterly Sunday. Lingering
moisture will keep PoPs mentionable through the weekend. Snow
levels Friday night/Saturday morning will be between 4- 5.5 kft
MSL and will rise Saturday night/Sunday morning to between
5.5-6.5 kft MSL. Temperatures behind the cold front Friday and
Saturday will be near normal.

The next system will be setting up to move through sometime
late Sunday/early Monday. Virtually every aspect of this feature
(amplitude, tilt, timing, intensity) has too much uncertainty
among long range models at this time to accurately predict too
much, however precipitation looks to return. With that, snow
levels are hinting at values below 4000 ft MSL as well... we
shall see!

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...ST
AVIATION.....JY
AIR STAGNATION...ST
SHORT TERM...JDS
LONG TERM....CH