497
FXUS65 KBOI 071055
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
355 AM MST Sun Dec 7 2025

.SHORT TERM...Today through Tuesday night...For today, light
precipitation will develop along a warm front as it lifts
through the region. Models have trended drier with the initial
band of precipitation this morning. Mountains will see light
snow develop by early afternoon. At lower elevations areas
closer to the foothills will see the best chance (30-50%)
through the day. A weak upper trough passage tonight will give
lower elevations the best chance for light rain while mtns see
additional rain and snow. Snow levels start around 4kft this
morning, rising to 5500-6500 feet this afternoon. This will give
mtn valleys a chance for light accumulations through early
afternoon (generally up to an inch). Above 6kft a general 3-6"
inches is expected through Monday morning.

For Monday through Tuesday night...We`re still looking at a lot
of rain and high mountain snow across Baker County and the
w-central Idaho mountains and Boise Mountains as these areas
stay locked under a deep moisture plume. The bones of the
forecast remain unchanged with precipitable water values rising
to the 99th percentile and mid- level winds of 30-60 mph from
late Monday through Tuesday night. The resulting steady light to
moderate precipitation will result in liquid amounts of 1-2"
and locally up to 2.5" through Tuesday night (with more to come
beyond that). Made minor adjustments to snow levels (NBM has
been running slightly high), but still looking at 7-8kft for
much of the period. A passing wave could briefly bring them down
to 6-6.5kft across the w-central Idaho mtns Tuesday, but they
quickly rebound Tuesday night. This will limit accumulation to
sites above 7kft, which will get pasted with 9-18" of wet snow.
Higher peaks will also see gusty winds to 45 mph along with the
rain/snow. Daytime mixing brings some of that wind to open
higher terrain on Tuesday where gusts of 25 to 40 mph are
forecast across SE Oregon and south of the Snake Plain. Being
mainly an orographic event, rain chances/amounts fall off
quickly across southeast Oregon and in the Snake Plain. Expect
little if any rainfall along the northern NV border and even the
Steens are going to miss out on much of the precipitation
during this period. Temperatures are well above normal and most
sites will see highs above freezing by Tuesday.

.LONG TERM...Wednesday through Sunday...Mid to late this coming
week continues to look wet and active. This is thanks to high
pressure situated off of the west coast streaming Pacific
moisture over our area. Mid-level flow at 500mb will be at a
notable 50-70 kt come Wednesday, this will provide a strong
moisture flux with PWs around the 97-99th percentile. Higher
elevations will see most of the fun, with wind speeds up to
40-55 kt down to 700mb (roughly 10,000ft MSL) orographic lift
will enhance precipitation in terrain. With that in mind, the
greatest precip chances and totals will generally be in the
terrain north of the Snake Plain, where the moisture flux is
greatest and lift is enhanced. Precipitation chances north and
east of the Snake plain will remain elevated with an 80-100%
chance of precipitation through Thursday morning. Precipitation
chance for that same period in and south of the Snake Plain
generally will be within the 30-70% range. I hate to be the
bearer of bad news for those who like snow recreation...But the
warm air advection in the strong flow aloft will send snow
levels skyward; ranging from 7-9 kft MSL on Wednesday, lowering
slightly to 6.5-8 kft MSL come Thursday. A consequence of the
high snow levels is that aside from the highest peaks, most of
the area will see rain as the dominate precipitation type. Over
the course of Wednesday morning through Friday morning, the
highest peaks could see up to a foot of additional snowfall...
but little to no accumulation is expected below 8 kft MSL.
Conversely, over that same time frame, Liquid precipitation
totals north and east of the Snake Plain are forecasted to be
0.75-1.75 inches. Generally 0.1-0.5 inches are expected in and
south of the Snake Plain, southeast Oregon will have a lower
range of up to a tenth. The strong flow aloft will stick around
over our area through Friday morning, and will translate down to
gusty winds at the surface. This will bring gusts of 25-50 mph
across the area, with the higher end of that range seen on ridge
tops and and typical trouble spots of the Snake Plain.

Precipitation chances and winds die down Thursday afternoon into
Friday as ridging begins to build overhead. This will push the
mid- level jet and moisture stream north of our area and bring
in higher pressure. This ridging will make valley inversions
possible, subsequently putting fog and low stratus in play to
end the week. With the warmer airmass, temperatures will be
15-20 degrees above normal throughout the long-term period.
Although the possibility of inverted conditions introduces
uncertainty into the late week temperatures as colder air could
get trapped near the surface.

&&

.AVIATION...Patchy fog early this morning. Rain and snow
coverage increasing along/north of KBNO-KMUO-KSUN line this
morning, then moving toward NV border by evening. MVFR/IFR and
local LIFR in precip and low clouds. Mtns obscured. Snow levels:
4k-5k feet MSL this morning, then 5k-7k feet this afternoon.
Surface winds: variable 10 kt, then SE-SW 5-15 kt this
afternoon. Winds aloft at 10kft MSL: W to NW 20-30 kt,
increasing to 30-40 kt by Sun/15Z.

KBOI...VFR with increasing clouds. Periods of rain and MVFR
conditions Sun/17Z through Mon/05Z. Foothills obscured. Surface
winds: SE 7-12 kt

&&

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

&&

$$

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SHORT TERM...DG
LONG TERM....NF
AVIATION.....NF