287
FXUS65 KBOI 100252
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
852 PM MDT Thu Oct 9 2025

.DISCUSSION...Temperatures climbed to around 10 degrees above
normal today, thanks to pronounced southerly flow aloft ahead of
a low pressure system residing along the PNW coast. Southeast to
southwest winds at the surface will ramp up overnight into
Friday. Gusts to 25-35 mph, locally up to 45 mph, are expected
for SE Oregon and much of SW Idaho by the afternoon period.
Temperatures are expected to be nearly as warm Friday as they
were today, except in Harney County where the cold front is
expected to arrive in the afternoon and evening from the west.
Showers and thunderstorms will increase Friday ahead of the
front in south-central/central Idaho, as well as along the front
in central Oregon, where moisture and instability become
favorable.

&&

.AVIATION...VFR. Areas of LLWS through early Fri morning.
Showers developing over the central ID mountains early Friday
morning. Then scattered showers and thunderstorms in
s-central/central Idaho in the afternoon, capable of outflows to
35-45 kt and small hail. Brief MVFR and mtn obscurations in
storms. Surface winds: variable 5-15 kt, becoming S-E 10-20 kt
after 10/06Z. Gusts to 25-40 kt beginning Fri morning. Winds
aloft at 10kft MSL: S 25-40 kt.

KBOI...VFR. LLWS developing late tonight/early Fri morning.
Surface winds: SE 5-15 kt overnight. Gusts increasing to 20-30
kt Friday morning and afternoon.

Weekend Outlook...Areas of mountain obscuration Sat morning
with showers and isolated thunderstorms. Showers continue into
Sunday with snow levels 5-7kft MSL and mountains obscured.
Periods of low VFR/MVFR in rain, and IFR/LIFR in snow. Breezy
conditions both afternoons with W-NW gusts of 20-30kt.


&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night...Unseasonably
warm and dry weather will continue through Friday. Highs will
run 10 to 15 degrees above normal, reaching the low to mid-80s
in the valleys today and Friday. This warming is driven by
strengthening southwest flow aloft ahead of an upper-level
trough moving south along the Pacific Northwest coast, which
will also bring increased southerly surface winds with gusts up
to 40 MPH.

By Friday, the trough will deepen into a closed low near the
Oregon coast, pulling a dry slot over southeast Oregon and
southwest Idaho and maintaining warm and dry conditions for much
of the day. The cold front remains the main focus, with its
passage expected Friday evening into early Saturday morning
across eastern Oregon and southwest Idaho. Ahead of the front,
the combination of increased tropical moisture from the
southwestern U.S. and rising instability will be the catalyst
for isolated evening thunderstorms across southern Idaho. The
greater coverage of precipitation will begin late Friday evening
with the arrival of the cold front. The chance of showers will
increase to 15-30 percent in the valleys. However, strong southwest
flow behind the front will favor upslope regions, with the west-
central Idaho and Boise Mountains expected to receive the brunt of
the moisture, where shower chances climb to 50-70 percent.

The trough moves inland by Saturday, maintaining scattered showers
of 20-40 percent in the valleys and 50-80 percent in the mountains.
Temperatures will drop to about 4-7 degrees below normal Saturday.
Winds will become west-northwest behind the front on Saturday
afternoon with gusts of 20 to 30 mph.

LONG TERM...Sunday through Thursday...Cooler temps and unsettled
conditions will be the name of the game throughout the long term
period. Early Sunday, the core of the trough that has sat west of
our area will pass over head. This is as it begins filling in an
embedding itself back into the main flow aloft. As this passes
overhead, snow levels will drop to 5-7kft Sunday. With these snow
levels, higher elevations will likely see precipitation in the form
of wintery mix/snow, especially early Sunday morning. Throughout the
day Sunday, locations above 6500 feet have a 40-80% chance of seeing
greater than 2 inches of snow (highest probabilities across higher
elevations in northeastern Valley county). By Monday, Ensembles
remain in good agreement of another trough digging down from British
Columbia and closing off into a low over California. This will put
our area in the warm sector; Thus, any snow accumulations over the
weekend will likely not stick around for too long. As this unfolds
on Monday, precipitation chances will taper off in lower elevations
and lower to  While uncertainty remains beyond Monday, This pattern
would favor below normal temperatures and periodic chances of
precipitation. Precipitation chances Tuesday and beyond will be 15-
40% across the majority of our area (higher chances found across
higher terrain).

&&

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

&&

$$

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