171
FXUS65 KBOI 011018 CCA
AFDBOI

Area Forecast Discussion...CORRECTED
National Weather Service Boise ID
318 AM MST Mon Dec 1 2025

.SHORT TERM...Today through Wednesday night...Clear, cold wx in
most of our CWA early this morning but satellite showed either
fog or stratus across northern Gooding and Lincoln Counties.
Webcams suggest stratus. Same in Baker County/OR. Cold, dry
northerly flow aloft will maintain quiet wx today with light
winds and slightly below normal temps. The upper air pattern
has an upper ridge in the north Pacific along 130W and a short
wave trough in the Gulf of Alaska. The trough is forecast to move
north of the ridge and onto the BC coast today, then southward in
BC tonight and into our area Tuesday, much like the weekend trough
that brought light snow to our CWA. The new trough should also
bring light snow. Latest MOS products indicate at most about a
half-inch, but up to 3 inches may accumulate on northern peaks and
in se Owyhee County along the NV border. Temperatures will also
be similar to the previous event, so roads below 4500 feet should
become only wet with little impact on travel. The trough and light
snow should exit into NV Wednesday morning followed by clearing
skies and breezy northwest winds.

.LONG TERM...Thursday through Monday...An upper level ridge off
the coast will begin to weaken on Thursday. This will allow the
jet stream to move south, ushering in wetter conditions as
early as Thursday night and Friday and continuing into early
next week. Strong westerly to northwesterly flow aloft is
expected to develop across the Pacific Northwest, with Pacific
moisture and embedded shortwave troughs resulting in periodic
precipitation across our area. There is good ensemble agreement
about the overall pattern.

Without a strong northerly component to the flow, these systems
should be fairly mild with mainly rain in the lower elevations
and rain and snow in the mountains. The first impulse is expected
to move through Friday into early Saturday. This will bring
increasing precipitation chances on Friday, peaking Saturday
morning at around 40-60% in the lower elevations and 60-90%
in the mountains. Snow levels should rise with the warm front
associated with this system to around 5500-7000 feet by Friday
night, then trend lower as cooler air aloft arrives. Snow levels
Saturday night through Monday are forecast to average 3500-5000
feet, with fluctuations higher and lower as additional impulses
pass through the area. Individual system timing and strength
are uncertain, but this pattern will continue a 10-30% chance
of precipitation in the lower elevations and 30-60% in the
mountains. Moderate to heavy snow totals will be possible
through early next week on higher peaks. Temperatures are
expected to average 5-10 degrees above normal through the
period, and the active pattern will result in breezy conditions.

&&

.AVIATION...Mainly VFR. Localized MVFR-LIFR in fog/low stratus,
mainly in the Magic Valley, near KBKE, and mountain valleys.
Conditions improving this morning. Then, MVFR-LIFR and mountain
obscuration in light snow and low clouds beginning this afternoon
across the central ID mountains. Precipitation will increase
across the area Tuesday morning. Snow levels 2500-3500 feet
MSL. Surface winds: variable up to 12 kt. Winds aloft at 10kft
MSL: NW 15-25 kt.

KBOI...VFR with increasing mid to high clouds today. A 30%
chance of a rain/snow mix Tuesday morning. Surface winds:
light and variable.

&&

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

&&

$$

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SHORT TERM...LC
LONG TERM....ST
AVIATION.....ST