342
FXUS65 KBOI 161522
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
922 AM MDT Thu Oct 16 2025

.DISCUSSION...Dry conditions today as northwest flow aloft
prevails behind a departing upper level low. Breezy conditions
will continue this afternoon through the Snake Basin, strongest
east of Boise with gusts 20 to 35 mph. Low temperatures tonight
will be looked at closely especially for the agricultural
valleys, as lows are forecast to dip into the mid 30s to around
40 degrees, close to frost thresholds. Additionally, winds will
be lighter than last night. However, high clouds will move
overhead tonight which may keep lows up a couple degrees.
Forecast remains on track and no updates anticipated this
morning.

&&

.AVIATION...MVFR-LIFR Low stratus in the Magic Valley and
patchy fog in SE OR expected to dissipate later this morning.
Skies generally clearing to VFR this afternoon. Valley fog
formation possible again tonight. Surface winds: W-NW 5-15 kt
with brief local gusts to 20 kt. Winds aloft at 10kft MSL: N-NW
10-20 kt.

KBOI...VFR with mostly clear skies. Surface winds: W-NW 5-10
kt, with gusts 15-20 kt possible this afternoon.

Weekend Outlook...Mostly clear conditions Friday through
Saturday. Sunday clouds increase with widespread precip moving
in after Sun/10Z from NW to SE lasting through the day. Best
chance for precip is in the north. Snow levels during precip
drop from 9 kft MSL Sun morning to 6 kft MSL Sun evening. Winds
NW 5-15 kt Fri, S-SE 5-15 kt Sat, and SW-SE 5-15 kt with gusts
up to 25-30 kt Sun.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Saturday night...Isolated showers
continue across portions of south central Idaho this morning,
mainly south of the Snake River plain. This activity is expected
to end by sunrise as the low moves east. Clearing skies are
expected today, though temperatures will remain around 5 degrees
below normal under dry northwest flow aloft. Afternoon wind
gusts of 20 to 35 mph will be common across the Snake Basin,
with the strongest winds east of Boise.

Light winds and clear skies tonight should allow temperatures
to fall into the mid to upper 30s in the western Snake River
Plain. At the moment, most valley locations look to remain at or
just above 36 degrees Friday morning, with the ensembles
showing only a 10 percent chance of temperatures below 36
degrees (the frost threshold) across the Boise Metro area.

On Friday, northwest flow aloft will continue as a shortwave
trough moves by to the north, which will keep winds breezy
during the day. Temperatures will warm a few degrees, but remain
a couple degrees below normal. Overnight lows will be slightly
colder with lighter winds, allowing sheltered areas in the
agricultural valleys to dip into the low to mid 30s. Ensembles
suggest a 40 percent chance of low temperatures reaching 36
degrees or colder. Due to this increasing risk, the potential
for frost will be monitored closely, as a Frost Advisory may be
warranted for Saturday morning.

The upper level ridge rebuilds back across the Pacific Northwest
on Saturday, with temperatures warming to near normal.

LONG TERM...Sunday through Thursday...There is now stronger
agreement between the long-range guidances on a longwave trough
digging across the Northwest region on Sunday. Widespread
precipitation will be expected throughout the area on Sunday,
with the heaviest episodes expected through the afternoon hours.
This pattern will bring a cooling trend, dropping snow levels
down into the 5000-6000 ft range late Sunday into early Monday.
As such, snowfall and mixed wintry precipitation remains highly
probable over higher elevations through early Monday. This
cooldown will drop peak temperatures from the mid 60s Sunday
down into the mid to upper 50s Monday and Tuesday for most
locations in the area. From the later hours of Monday through
the end of the extended period, a broad upper ridge is expected
to build and linger over the area, bringing a slight drying and
warming trend. A weak shortwave trough is expected to break off
the British Columbia coast and dig quickly across the OR/ID
central mountains on Wednesday, but is expected to be dry and
weak. Peak daytime temperatures are expected to slowly trend
back up into the lower to mid 60s for most locations Wednesday
through Thursday.

&&

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

&&

$$

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DISCUSSION...ST
AVIATION.....JM
SHORT TERM...JDS
LONG TERM....JY