588
FXUS65 KBOI 091056
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
356 AM MST Sun Nov 9 2025

.SHORT TERM...Today through Tuesday night...High pressure
aloft will keep dry and stable conditions over the region
through the period. An upper trough tracking along the US/Canada
border will weaken the ridge on Monday, increasing winds and
cooling temperatures aloft. High clouds will work through the
ridge today and Monday, with skies clearing behind the trough.
At the surface, dry conditions will be accompanied by warming
temperatures today and Monday along with light winds. Mountains
will get a head start on warming as lower elevations lag under a
temperature inversion. Cooling aloft on Tuesday will be realized
at higher elevations, while improved mixing translates to a few
degrees of warming at the lowest elevation sites (ID/OR border
area).

.LONG TERM...Wednesday through Sunday...A rebuilding ridge axis
will shift east of the area on Wednesday, opening southwest
flow aloft as a deep trough approaches the West Coast. Models
remain in agreement on bringing the trough inland on Thursday,
spreading rain and high elevation snow from west to east during
the day. The best chance for precipitation (60-80%) comes
Thursday through early Friday along the leading edge of the
upper trough/cold front. A chance of rain/snow remains in the
forecast through Sunday, though signs of brief ridging ahead of
the next trough could bring a period of drier conditions on
Saturday. Snow levels will start around 8kft MSL on Thursday,
dropping to between 4500-6000 feet for Fri-Sun. Light to
moderate accumulations are expected above 6kft for the Thur/Fri
period. Temperatures cool to near normal for Friday through
Sunday.

&&

.AVIATION...VFR under periods of high clouds. Surface winds:
less than 10 kt. Winds at 10kft MSL: W-NW 5-15 kt.

KBOI...VFR with surface winds less than 10 kt.

&&

.AIR STAGNATION...A temperature inversion will strengthen over
the area through Monday as a sharp upper ridge brings quick
warming aloft. This will result in lowering mixing heights which
reach a minimum of roughly 1500-2000 feet AGL on Monday. Some
improvement is expected Tue/Wed after the passage of an upper
trough brings in cooler air aloft. While surface winds remain
light, the NBM shows mixing heights increasing to 2-3kft AGL
Tue/Wed. The dry air mass and lack of snow cover and will limit
fog development through this event. A pattern change later in
the week will replace the stagnant air mass with cooler and
wetter conditions Thur/Fri.

&&

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

&&

$$

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SHORT TERM.......DG
LONG TERM........DG
AVIATION.........DG
AIR STAGNATION...DG