102
FXUS65 KBOI 070952
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
252 AM MST Thu Nov 7 2024

.SHORT TERM...Today through Saturday night...An upper-level
ridge will stay over the area through Friday, bringing warmer
air over the colder air trapped in the valleys, keeping that
inversion in place. The inversion should be at its peak strength
on Friday as the ridge reaches its highest point. By Saturday,
the ridge will start to weaken as an upper-level trough
approaches the west coast. This shift will bring stronger
surface winds and cooler air aloft, which should help break up
the inversionthough it`s likely to stick around until Monday.
Skies should stay mostly clear today through Friday night,
keeping valley temperatures below normal.

.LONG TERM...Sunday through Thursday...The pattern is expected
to become more active in the extended forecast, with a series of
troughs moving through the region. The first of these systems
is anticipated early Sunday, with good agreement across forecast
models. This initial trough will be relatively weak as it moves
through eastern Oregon and the west-central mountains of Idaho,
bringing a 20-50% chance of precipitation. Snow levels are
forecast to stay between 5,000 and 7,000 feet. The trough
doesnt look strong enough to break the valley inversion.

A stronger low-pressure system from the Gulf of Alaska is
expected to arrive Monday into Tuesday. There`s still some
uncertainty around the timing of the cold frontal passage, which
will be the key driver of widespread precipitation. Current
consensus suggests it will move through later on Monday. Snow
levels should remain high, between 7,000 and 8,000 feet for most
of the event, dropping to around 4,000 feet following the
front. There`s approximately a 50% chance of a quarter-inch of
rain in the valley and up to a 70% chance of moderate snow
accumulations (6 to 12 inches) above 6,500 feet through Tuesday
morning.

By Tuesday, we can expect rain and snow showers across
the region, accompanied by breezy, colder northwesterly winds as
the low pressure exits. A short dry period may follow on
Wednesday before the next upper-level trough approaches on
Thursday.

&&

.AVIATION...VFR. Mostly clear skies. Surface winds: variable
less than 10 kts. Winds aloft at 10kft MSL: N-NW 25-30 kt.

KBOI...VFR. Clear skies. Diurnal winds less than 10 kt.

Weekend Outlook...Increasing mid clouds Saturday. MVFR
conditions possible Sunday with light precipitation across
southeast Oregon and West Central Mountains of Idaho with trough
passage. Snow levels around 6000 feet. Light east-southeasterly
winds.

&&

.AIR STAGNATION...An inversion along with light winds will
lead to low mixing heights and stagnant conditions in the
valleys through at least Saturday. Slight improvement is
expected Sunday. A strong storm from the Gulf of Alaska should
greatly improve ventilation on Monday.

&&

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

&&

$$

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SHORT TERM...JDS
LONG TERM....JDS
AVIATION.....JDS
AIR STAGNATION...JDS