148
FXUS65 KBOI 081650
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
950 AM MST Fri Nov 8 2024

.DISCUSSION...Smoke and haze are lingering in the Treasure
Valley as the inversion begins to strengthen this morning. This
is leading to poor air quality in the Boise metro area and near
Idaho City. Stagnant conditions will continue through Saturday,
with some reduction in the inversion still looking favorable as
the shortwave passes through the region on Saturday night. More
expansive precipitation still looks to move into the region on
Monday evening, beginning a pattern shift to cool and wet
conditions next week. No updates necessary to the forecast.

&&

.AVIATION...VFR, except mountain valley fog through this
morning, bringing localize LIFR conditions (KMYL). Surface
winds: less than 10 kt. Winds aloft at 10kft MSL: N to NW
5-15 kt.

KBOI...VFR with mostly clear skies and light winds. Patchy smoke
and haze near the surface and over the foothills from area pile
burns.

Weekend Outlook...VFR Saturday. Ceilings lowering Sat night with
light precipitation. Potential for MVFR/IFR in the northeast
Oregon/west-central Idaho mountains, and mountain obscuration. Snow
levels: 5500-6500 ft MSL Sat night. Improving conditions by Sunday
afternoon. Light surface winds and SW-W 10-20 kt winds aloft.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Sunday night...An upper-level ridge
will remain over the area through Saturday, sustaining the
valley inversion. Today, the inversion is expected to reach peak
strength as the ridge achieves its maximum amplification. By
Saturday, however, the ridge will start to weaken with the
approach of an upper-level trough from the west coast. This
trough is projected to move inland Saturday night, crossing the
forecast area early Sunday. As it progresses inland, the trough
will weaken considerably, limiting precipitation mainly to the
central Idaho mountains, where amounts up to 0.15 inches are
possible. Snow levels will remain high, between 5,500 and 6,500
feet on Sunday, with light snow accumulations expected on
mountain peaks. Despite the troughs weakening, it should be
strong enough to significantly reduce the inversion on Sunday,
although it may not fully dissipate it. Temperatures will remain
below normal today but are expected to increase to 2 to 4
degrees above normal on Saturday and Sunday.

LONG TERM...Monday through Friday...A series of moist, Gulf of
Alaska troughs will arrive beginning Monday. Rain and snow
chances are relatively high (60-90% chance) Monday for most
areas, with snow levels lowering to around 4500-5500 feet MSL by
Monday night. Winds will also increase ahead and behind the
cold front on Monday. While this trough is forecast to exit
Tuesday morning, a prominent fetch of Pacific moisture will
continue to stream precipitation (mainly) over northeast OR and
central ID through Thursday, with a prolonged period of snowfall
expected above 5500-6500 ft MSL. Precipitation chances increase
once again across the rest of southeast OR and southwest ID
with the next Gulf of Alaska trough arriving Fri/Sat.
Temperatures are forecast to remain within a few degrees of
normal through the week.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Air Stagnation Advisory until 5 AM MST Sunday
     IDZ011>014-028-033.
OR...Air Stagnation Advisory until 5 AM MST /4 AM PST/ Sunday
     ORZ061>064.

&&

$$

www.weather.gov/Boise

Interact with us via social media:
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise

DISCUSSION...SA
AVIATION.....SA
SHORT TERM...JDS
LONG TERM....SH