Area Forecast Discussion
Issued by NWS Boise, ID

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062
FXUS65 KBOI 171600
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1000 AM MDT Fri Oct 17 2025

.DISCUSSION...Still expect morning cloud cover break up through
the day giving way to mostly clear skies this afternoon.
Northwest flow aloft will translate to the surface across higher
terrain. Clearer skies tonight and light winds will allow for
another chance at frost in the lower Snake Plain. Current
forecast is on track for this morning.

&&

.AVIATION...Broken-overcast skies for the area, but VFR outside
of mountain obscuration. Cloud cover has dropped any chance of
fog this morning/early afternoon. Surface winds: variable less
than 10 kt, becoming W-NW 5-15 kt this afternoon. Winds aloft at
10kft MSL: W-NW 15-30 kt.

KBOI...VFR with mostly clear skies. Surface winds: SE 4-8 kt
becoming NW 6-10 kt this afternoon. Some variability is possible
this afternoon and tonight.

Weekend Outlook...Mostly clear conditions on Saturday with
patchy mountain valley fog and frost in the AM. Sunday clouds
increase with scattered showers north of a KBNO-KBOI line after
Sun/12Z. Snow levels during precip drop from 8000 ft MSL Sun
morning to 5000 ft MSL Sun evening. Surface winds: S-SE 5-15 kt
Sat, and SW-SE 5-15 kt with gusts up to 25-35 kt Sun.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Sunday night...High clouds
associated with an approaching upper level trough have
overspread the area this morning. These clouds to not appear
thick enough to prevent pockets of frost from developing in the
Upper Treasure Valley east of Boise and the Western Magic
Valley, with lows still expected to fall into the mid to upper
30s.

The trough will move west to east across the Pacific Northwest
just to our north later today bringing another day of breezy
winds and mostly dry conditions. The only chance for
precipitation (10 to 20 percent) will be in the West Central
Mountains. High temperatures will increase a few degrees from
yesterday, especially in southern areas, and will be near
normal.

Pockets of frost area again expected Friday night in the lower
valleys as the clouds clear out and winds diminish behind the
exiting trough.Consequently, the Frost Advisory has been
expanded through the entire Treasure Valley into the Western
Magic Valley for Saturday morning, with lows forecast between
33 to 37 degrees.

On Saturday, an upper level ridge will briefly move overhead,
bringing lighter winds and mostly sunny skies. Winds will start
to increase Saturday night ahead of the next system. This upper
level trough and its associated cold front will reach the area
Sunday afternoon, bringing increased winds, cooler temperatures,
and precipitation (30 to 60 percent chance) mainly to the
central Idaho Mountains. Snow levels will fall to near 6500 feet
for light snow, generally less than an inch.

LONG TERM...Monday through Friday...A trough will deepen over
southern Canada and the Pacific Northwest on Monday, bringing
cooler temperatures and high terrain precipitation. Snow levels
will drop to 5000-6000 feet MSL, but the extent of the moisture
will remain over Baker County and the West Central Mountains.
Limited accumulation of precipitation is anticipated by Monday
evening. The trough will then weaken and move east as a ridge of
high pressure develops over the Western US. This will bring
warm and dry conditions to the region through at least Thursday.
After Thursday, ensemble variance increases in timing and
extent of the next system. All solutions agree on some deep
trough or closed low moving onshore late next week and bringing
much cooler temperatures and widespread precipitation with an
atmospheric river set up. Forecast confidence is low in exact
impacts from this system, but the probability of valley rain and
mountain snow with much colder temperatures is higher for
Friday into the weekend.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Frost Advisory until 9 AM MDT Saturday IDZ012-014-016.
OR...Frost Advisory until 9 AM MDT /8 AM PDT/ Saturday ORZ064.

&&

$$

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DISCUSSION...DG
AVIATION.....JM
SHORT TERM...JDS
LONG TERM....SA