068
FXUS65 KBOI 120926
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
226 AM MST Wed Nov 12 2025

.SHORT TERM...Today through Friday night...Mild and dry weather
through Thursday morning as an upper ridge and inverted
conditions keep winds light and temperatures very warm for this
time of year. High temps Wednesday and Thursday are as high as
15-20 degrees above normal, peaking Thursday with some Snake
Plain locations potentially seeing just under 70 degrees. A
persistent weak inversion will make for hazy conditions, with
some morning mist possible.

Off the West Coast, a low pressure
trough amplifies, leading to increasing clouds through the first
half of the short term. By Thursday morning, the leading edge of
the moisture supports a slight chance of precipitation with snow
levels still high at 8-9 kft MSL. The leading edge will also
bring gusty winds on Thursday, with gusts 25-35 mph in SE Oregon
and SW Idaho highlands and ridges. This, and a cold front
Thursday night/Friday morning with increased precipitation
chances, will scour out the inversion. Some uncertainty is
apparent amongst models as the front moves through, but the
chance of precipitation for high terrain is still 80-90% and
30-50% for lower elevations. The uncertainty has led to a
slightly higher snow level forecast behind the cold front, with
snow levels on Friday now 6-8 kft MSL and temps 5 degrees above
normal, dropping expected snowfall on ridges significantly. The
expected rainfall or liquid equivalent for mountains is still in
the realm of 0.3-0.5 inches, and less than 0.1 inches for lower
elevations. Precipitation continues through Friday, with the
best chances in the morning. The high- amplitude trough becomes
a closed low over SoCal by the end of Saturday, deamplifying the
jet stream over the region and indicating a brief break in the
long term.

.LONG TERM...Saturday through Wednesday...With the region in the
deformation zone of a closed low off the SoCal coast and the jet
stream to the north on Saturday, only a slight chance of
precipitation for Baker and Valley counties exists on Saturday.
Model run-to-run variability has been significant in the track
of the closed low Sunday onwards (as is usual with closed
lows, much to my and my forecast`s dismay). The closed low
amongst ensemble means seems to track northeastward, just
clipping the area Sunday night with Pacific moisture. What would
have been a fairly shortlived system, will be lengthened by a
new trough developing almost immediately behind the closed low.
The vast majority of models depict this trough, leading to high
confidence in a wetter and cooler start to Monday as its cold
front moves through. This will drop temps down to near normal
Monday through Wednesday with snow levels at 4-5 kft MSL. This
would give ridgelines and passes the couple of inches of snow
they now miss out on in the Thursday system, possibly even
impacting high elevation towns such as McCall with some snow
accumulation.

&&

.AVIATION...VFR and increasing high-level clouds. Hazy/Misty
conditions sporadically in valleys due to a weak inversion.
Isolated virga/light rain showers Wednesday afternoon. Surface
winds: Variable up to 10 kt. Winds aloft at 10kft MSL: SW 10-20
kt.

KBOI...VFR. Surface winds: Light and variable.

&&

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

&&

$$

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SHORT TERM...JM
LONG TERM....JM
AVIATION.....JM