044
FXUS65 KBOI 092114
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
214 PM MST Sat Nov 9 2024

.SHORT TERM...Tonight through Monday night...A surface inversion
has begun to weaken slightly this afternoon. This combined with
the reduction in area controlled burns has allowed for reduced
smoke near the surface this afternoon, although the Treasure
Valley still has remnant haze. Stagnant conditions will continue
over the Boise Mountains-Treasure Valley through Monday
morning, with mixing increasing north as the shortwave trough
passes over the region. Light precipitation and a slight
increase in wind will reduce the largest impacts of the air
stagnation in Baker County-West Central Mountains, therefore the
air stagnation advisory has been cancelled for those regions.
Precipitation amounts from this system will be minimal, with
less than a tenth of an inch of rain below snow levels around
6000-7000 feet and around 1-2 inches of snow above those snow
levels. Temperatures will be around 3-5 degrees above normal
through the short term period, with light winds and mostly clear
skies outside of the precipitation through early Monday.

A more significant trough will move into the region on Monday
afternoon, bringing cooler temperatures and widespread
precipitation anticipated. Precipitation amounts are expected to
remain light across the valleys, with a significant decreasing
trend in the models in QPF totals. Snow levels will be around
5000-6500 feet on Monday afternoon, decreasing to around
4000-5000 feet by Monday night. Snow totals will range from 1-3
inches across mountain valleys, with higher summits seeing
around 4-8 inches by the end of the initial event early
Tuesday.

LONG TERM...Tuesday through Saturday...An upper trough and
accompanying cold front move through on Tuesday for a round of
precipitation, mainly in the higher elevations across the north,
with snow levels ranging from 4000-5000 feet. Models/ensemble
members are in good agreement with regard to timing and precip
amounts with 1-3 inches of additional snowfall forecast for central
Idaho. Gusty post-frontal winds to around 35 mph subside late in the
day. A generally drier W-NW flow aloft develops Tuesday night, but
there is still a 30-60 percent chance of lingering light precip (w/
snow above 4000 feet) in the northern mountains. Southwest flow
aloft develops on Wednesday as the next upper trough approaches the
west coast. Precip chances initially favor the higher elevations in
the north, but increase area-wide Thursday and Friday as the trough
moves into the Pacific Northwest. There remains a lot of uncertainty
with the details of this system, but most areas have at least a 30
percent chance of receiving measurable precip. Snow levels ahead of
the trough are well above valley floors, at least 5500 feet
Wednesday and Thursday, but lower to 4000-5000 feet on Friday. There
is also substantial uncertainty as to whether or not the trough
exits to the east for drier conditions on Saturday. Precip chances
lower to 15-30 percent and are limited to the higher elevations.
Temperatures trend from slightly above normal midweek to slightly
below normal by the end of the week. Winds will be breezy to locally
windy at times.

&&

.AVIATION...VFR. Patchy valley MVFR/IFR fog developing after Sun/05Z
in the central ID mtns (including KMYL). Ceilings lowering overnight
with light rain/snow and MVFR/IFR in the northeast OR and west-
central ID mtns. Mountains becoming obscured. Areas improving to VFR
by Sun afternoon, except lingering precip and mtn obscuration in
west-central Idaho. Snow levels lowering to 5500-6500 ft MSL tonight
increasing to 6000-7000 ft MSL on Sunday. Surface winds: variable
less than 10 kt. Winds aloft at 10kft MSL: W-SW 15-30 kt.

KBOI...VFR. Variable surface winds less than 10 kt. Increasing mid-
high clouds. A 20 percent chance of light rain Sunday morning.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Air Stagnation Advisory until 5 AM MST Monday IDZ012>014-028.
OR...Air Stagnation Advisory until 5 AM MST /4 AM PST/ Monday
     ORZ061-063-064.

&&

$$

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SHORT TERM...SA
LONG TERM....BW
AVIATION.....BW