420
FXUS65 KBOI 040346
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
846 PM MST Mon Nov 3 2025

.DISCUSSION...No updates to the previous forecast this evening.
Clouds and rain increasing from NW to SE as an upper low
approaches the coast. This band of precipitation will drop up to
0.25 inches of rain in the mountains, with minimal accumulation
of snow above 7.5 kft MSL. Lower elevations may see sprinkles,
with much of the area at around a 40% chance of precipitation.
Winds have also come up in SE Oregon, and will be gusting 20-30
mph through Tuesday afternoon.

The core of the upper low moves in Wednesday afternoon through
Thursday evening, with wind gusts up to 40 mph and precipitation
chances 50-80%. Snow levels with the colder airmass drop to 6
kft MSL, with a few inches of snow possible on ridges and high
elevation passes like near Banner Summit. Otherwise mountains
receiver 0.25 to 0.5 inches of rain, and lower elevations less
than 0.25 inches. The unsettled wet and cool pattern persists
through Saturday, where models show a ridge building into the
region.

&&

.AVIATION...VFR. Precipitation moving from NW to SE tonight.
Periods of IFR/LIFR for mtns in precip/low clouds with
mountains becoming obscured. Snow levels 6.5k-8k feet MSL,
lowest to the NW. LLWS up to 35 kt possible. Surface winds:
SW-SE 5-15 kt with gusts 25-35 kt in SE Oregon and near ID/NV
border. Winds aloft at 10kft MSL: W-SW 35-50 kt.

KBOI...VFR. Surface winds: SE 5-12 kt. Light rain arriving
after midnight, with less than 10% chance of MVFR. 25 kt LLWS
possible between Tue/08Z and Tue/12Z.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...High clouds
will increase this afternoon ahead of the next in a series of
systems poised to move through the region next weekend. A system
is moving inland across the Pacific Northwest, reaching
southeast Oregon late tonight. This will spread rain and high
mountain snow along a cold front across northern areas this
evening, then into southern areas by mid Tuesday morning. Snow
levels will be 7500 to 9000 feet MSL tonight, dipping to 6000 to
8000 feet Tuesday morning. Overall precipitation amounts will
be light. Strong southwest flow aloft will, however, result in
higher precipitation totals in the central Idaho mountains, with
0.20 to 0.50 inch expected and locally up to 0.75 inch
possible. Lower amounts, around 0.05 inch or less, are expected
elsewhere.

This will be followed by a warm front moving north across the
area Tuesday afternoon and evening, bringing additional light
precipitation and boosting snow levels up to around 8000 feet.
The highest chance for precipitation with this front is across
southeast Oregon, though light rain is possible across much of
southwest Idaho. A brief break in precipitation should then
develop late Tuesday night into Wednesday morning ahead of a
deeper trough. This trough will push a cold front across our
area on Wednesday, bringing stronger winds, especially across
portions of southeast Oregon and Idaho south of the Snake River
where afternoon gusts 35 to 50 mph are expected.

Precipitation will redevelop Wednesday afternoon through
Wednesday night. Strong west southwest flow will bring moderate
precipitation totals to the mountains with light amounts
expected elsewhere. Snow levels will lower behind the front to
6000 to 7000 feet by late Wednesday night, with several inches
of snow expected on the higher peaks.

LONG TERM...Thursday through Monday...This active period of
weather will carry over from the short term, with the upper-level
trough in the Gulf of Alaska impacting the pattern for the area.
Thursday starts with westerly flow aloft and the area still being
impacted by a shortwave and moisture that moved through Wednesday
night. Precipitation will still be supported, especially for high
terrain, with PoPs in higher elevations at 50-80%. Brief low
amplitude upper-level ridging will quickly move over the area
afternoon/evening Thursday, before immediately giving way to another
surge of moisture from another shortwave trough. Widespread
precipitation is expected beginning 06z/Fri in SE OR and 12z/Fri in
SW ID. Precipitation amounts may be considerable for favored upslope
areas such as the west-central ID/Boise mountains, with
approximately 50% chance of receiving at 0.50" or greater liquid
equivalent in those areas. Meanwhile, some valley shadowing will be
likely in this pattern due to moderately strong mid-level winds.
General trends of QPF/accumulation over the past few days have been
consistently trending down, however, this will still be a wet end to
the work week. The bulk of the colder air will remain north of the
area with this storm, and therefore temperatures are expected to be
within a few degrees of normal for both Thursday and Friday. Snow
levels will oscillate between 6000-7500 feet MSL ahead of/during the
trough passage. Light snow amounts are forecast above 6000 feet,
with several inches forecast above 7000 feet. Precipitation chances
greatly decrease Friday night into Saturday as a very potent, high
amplitude upper-level ridge builds over the area. Thus, a much drier
pattern and above average temperatures will hold to bring a quiet
weekend.

&&

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

&&

$$

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DISCUSSION...JM
AVIATION.....JM
SHORT TERM...JDS
LONG TERM....CH