105
FXUS65 KBOI 081539
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
939 AM MDT Wed Oct 8 2025

.DISCUSSION...Unseasonably warm conditions are expected today
and Thursday, with temperatures running about 10 to 12 degrees
above normal. Increasing southwesterly flow aloft, in response
to a developing low-pressure system off the Pacific Northwest
coast, should help boost surface winds from the south-southeast
today. This flow regime will aid high temperatures in reaching
the upper 70s today and the low 80s on Thursday, while
maintaining mild low temperatures overnight. Clouds will
increase later on Thursday, and the threat for showers will
begin on Friday with the passage of a cold front. Until then,
expect early fall-like conditions across the forecast area. No
updates are needed at this time.

&&

.AVIATION...Mostly VFR. MVFR/IFR in sheltered mtn valleys with
fog/low stratus. Clearing to VFR by 17z. LLWS developing early Thu
morning. Surface winds: E-SE 5-15 kt with gusts to 25 kt in the
Snake Plain. Winds aloft at 10kft MSL: SW 15-25 kt

KBOI...VFR and clear. LLWS possible early Thu morning. Surface
winds: SE 10-15 kt with gusts up to 25 kt this afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Friday night...An upper level
trough near Haida Gwaii will gradually move south along the
coast through Thursday, shifting the flow aloft to the southwest
and bringing warmer temperatures to the region. Southwest-
southeast winds and will gradually increase through Friday ahead
of the cold front. Temperatures Wednesday warm around 5 degrees
and a few more degrees by Thursday. As the system moves south
along the coast, high clouds increase across central OR.
Thursday is likely the warmest day of the period for eastern OR
while Friday is forecast to be the warmest day of the period for
southwest Idaho. The trough becomes a closed low and remains
off the OR coast, with a dry slot developing over southeast OR
and southwest ID for much of the day Friday before a cold front
arrives Friday evening. Showers chances increase to 20-40
percent late in the evening. With pronounced southwest
flow continuing, favored areas for upslope flow will receive
the brunt of the moisture, such as the west-central Idaho and
Boise Mountains (60-80% chance).

LONG TERM...Saturday through Wednesday...The trough moves
inland by Saturday, with showers increasing to 40 percent in
the valleys and continued 60-80 percent in the mountains. Winds
become west-northwest on Saturday afternoon with gusts to 20 to
30 mph during the afternoon behind the front. Forecast
confidence beyond Sunday is low, but favors much cooler and
unsettled early next week with a trough somewhere over the
Pacific Northwest. Forecast models continue to struggle with
current and recent tropical systems disrupting and enhancing the
jet stream, particularly in the eastern Pacific near Cabo San
Lucas and in the western Pacific Ocean. Temperatures cool 10-20
degrees on Saturday and another 5-10 degrees on Sunday.

&&

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

&&

$$

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