677
FXUS65 KBOI 020341
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
841 PM MST Mon Dec 1 2025

.DISCUSSION...A weak system is currently moving through the
area this evening. This system has produced only brief, light
snow flurries, primarily staying outside of the main Snake River
Plain. Web cameras across Harney and Malheur Counties have
shown only a few snowflakes, and the Burns ASOS station
reported a trace of precipitation consisting of a light rain and
snow mix. The remainder of these light showers will continue
tracking southeast across southwest Idaho for the rest of the
evening, with a low probability of any measurable snow
accumulation.

A stronger weather system is expected to arrive on Tuesday,
driven by the passage of a cold front. Increase in instability,
will lead to scattered showers, which could include rain, snow,
and graupel. These showers are forecast to begin across the
northern zones late Tuesday morning and then spread south across
the remainder of the area through the afternoon. Lower valleys
will most likely experience rain, though any particularly strong
showers could briefly produce graupel. Snow amounts above 4,000
feet will be minimal, with a possibility of up to half an inch.
Northwesterly winds will increase sharply with the cold frontal
passage Tuesday afternoon, with gusts up to 30 MPH expected.

&&

.AVIATION...Mainly VFR. Isolated light snow/mix moving SE
toward ID- NV border tonight. Then, scattered showers arriving
from N to S after Tue/09Z, continuing through Tue night. Tue
snow levels 2k-4k feet MSL. IFR/LIFR in snow. Areas of mtn
obscuration. Surface winds: light and variable, then W to NW
5-15 kt Tue afternoon. Gusts to 20- 30 kt from KMUO to
KJER/KTWF, and in SE Oregon. Winds aloft at 10kft MSL: NW 20-35
kt.

KBOI...VFR tonight. Scattered rain/mixed showers in Treasure
Valley and surrounding foothills between Tue/14Z-Wed/02Z.
Afternoon will be best chance for brief showers at KBOI. No
snow accumulations expected. Surface winds: light and variable,
then NW 5-12 kt Tue afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...A weak system is
moving across north central OR, northern ID and eastern WA this
afternoon. This will bring light precipitation to the area later
this afternoon into the evening. A cold front situated near
Vancouver Island will move through the area on Tuesday, bringing
cooler air aloft and unstable air. This will provide enough lift
for rain and snow showers Tuesday during the day, with snow
levels around 3000-4000`. Minimal precipitation expected with
this system, with snow accumulations around 1-2" in the
mountains. Dry conditions on Wednesday following the front. The
system will bring low clouds and fog to the area on Wednesday
as upper level ridging builds in behind the cold front. Forecast
confidence is low on the post frontal cloud development though.
Temperatures remain near normal.

LONG TERM...Thursday through Monday...An unsettled pattern will
develop through the period. A upper level ridge situated off of
the west coast will begin to break down throughout the day
Thursday. While the first shortwave Thursday morning lacks
moisture to provide anything more than increased clouds, it will
help flatten the ridge allowing for Pacific moisture to start
streaming into our area behind it. This moisture advection will
allow for increasing precipitation chances Thursday evening.
Precipitation chances will increase to 10-20% in lower
elevations and 20-60% in higher elevations (highest in the West
Central Mountains) by Thursday night. Another shortwave is set
to move across our area Friday/early Saturday, bringing the
highest precipitation chances of the period Saturday morning.
With chances increasing to 40-60% across lower elevations and
60-90% in higher elevations (per usual, chances higher in the
West Central and Boise Mountains).

With the jet stream overhead, there will be multiple periods of
precipitation into early next week as shortwaves come and go.
While  it is too far out to resolve the exact timing and
strength, this pattern will support precipitation chances
continuing into Monday. Snow levels will vary throughout the
week, climbing to 5.5-7.5kft MSL late Friday. Beyond Friday,
snow levels will trend down to 4.5- 5.5kft MSL come Monday.
Temperatures will stay 5-10 degrees above normal throughout the
period.

&&

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

&&

$$

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DISCUSSION...JDS
AVIATION.....SH
SHORT TERM...KA
LONG TERM....NF