Hansen, Idaho Weather Forecast Discussion

426
FXUS65 KBOI 060246
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
846 PM MDT Sun Oct 5 2025
.DISCUSSION...Clear skies and diminishing winds tonight will
create ideal conditions for radiational cooling across the area,
leading to a chilly night. The most significant impacts are
expected in the Western Magic Valley, where a Frost Advisory is
in effect for temperatures forecast to drop into the low to mid
30s. While higher elevation valleys have a high probability of
reaching freezing temperatures, the Treasure Valley will likely
remain slightly warmer, with lows in the upper 30s. A warming
trend is forecast to begin Monday, bringing abundant sunshine
and warmer afternoons through at least the middle of the week.
&&
AVIATION...VFR. Skies mostly clearing with some mid-to-high clouds
over E`rn OR. Snow levels 6000-7000 ft MSL. Patchy valley fog and
scattered low stratus clouds overnight, primarily in sheltered
mountain valleys (near KMYL). Surface winds: NW-NE 5-15 kt, with
gusts up to 20 kt through the Snake Plain becoming variable less
than 10 kt tonight after 05Z. Winds aloft at 10 kft MSL: N-NE 5-15
kt.
KBOI...VFR. Surface winds: NW 5-10 kt, shifting to SE 5-10 kt
tonight after 05Z.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday night...Breezy northwesterly
winds are kicking up across the Snake River Valley this
afternoon, with cool temperatures and a few cumulus clouds
building over higher terrain. Isolated showers with a stray
lightning strike will continue over the Southern Boise
Mountains, dissipating after 6pm MDT. Clouds will begin to
clear overnight, with temperatures reaching near or below
freezing in higher elevation valleys. Therefore, a frost
advisory has been issued for the Western Magic Valley with
overnight lows anticipated to be around 30-37F. Winds will die
down quite a bit overnight, with patchy fog likely in sheltered
valleys. Fog will mix out by mid morning, with another day of
cool and dry conditions anticipated. A Pacific high will then
build in on Tuesday, with temperatures increasing across the
region.
LONG TERM...Wednesday through Sunday...Dry southwesterly flow
will bring warming and drying conditions through Thursday.
Temperatures will climb to about 3-5 degrees above normal
through the midweek, then a return to a cool and wet pattern
will occur. Model agreement has increased with ensembles
agreeing on the track of a deep upper level low moving into the
Pacific Northwest on Friday, bringing cooler temperatures, gusty
winds, and high terrain showers to the area.
There is still large discontinuity on the timing of the
heaviest precipitation, with the GFS/Canadian deterministic
models showing a much slower evolution compared to the ECMWF. By
Sunday, the trough axis will move east, bringing cold
temperatures and lingering showers over higher terrain. This
will be a much colder air mass than earlier this weekend, so
there is a potential for light snow down into population centers
in mountain areas like McCall and Idaho City on Sunday.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Frost Advisory from 2 AM to 10 AM MDT Monday IDZ016.
OR...None.
&&
$$
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DISCUSSION...JDS
AVIATION.....JY
SHORT TERM...SA
LONG TERM....SA

NWS BOI Office Area Forecast Discussion