032
FXUS65 KBOI 052342
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
542 PM MDT Sat Sep 5 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...
- Slightly warmer today but still cooler than normal.

- Widespread showers and isolated thunderstorms late Sunday
  through Monday.

- Cooler Monday, then warming through Friday.

&&

.SHORT TERM /Through Monday Night/...
Issued 228 PM MDT SAT SEP 5 2026
An upper level trough will remain along the Oregon coast over
the next day with a weak front stalled out over southwest
Idaho.  Showers and thunderstorms will generally be confined
to western Baker County in OR and northeast of Valley County in
ID this afternoon. A weak wave will move across NV late this
afternoon and trigger some isolated showers and thunderstorms
tonight over southwest Idaho through early Sunday morning. The
trough will begin to move inland on Sunday across southern OR
Sunday afternoon. Showers and thunderstorms increase late Sunday
afternoon across eastern OR, with isolated thunderstorms over
the west central ID mountains. The upper level low will track
across southern ID early Monday morning, with showers and
isolated thunderstorms areawide. The precipitation will quickly
taper off across eastern OR and the Snake Basin in southwest ID
early Monday morning, with lingering showers over the central ID
mountains through Monday afternoon. A convergence zone will set
up in wake of the Wallowas late Monday afternoon keeping showers
and thunderstorms north of McCall late into the evening.

&&

.LONG TERM /Tuesday through Saturday/...
Issued 228 PM MDT SAT SEP 5 2026
begins to move east on Tuesday with drier and warmer conditions
through Friday under westerly flow aloft. A trough from the Gulf
of Alaska will move south along the BC coast into the Pacific NW
by Saturday with cooler conditions possible next weekend.
Uncertainty remains elevated in the extended period, as
tropical activity in the Pacific enhances the jet stream. Models
do not handle the energy transfer well in these situations so
expect lots of changes in the far extended period over the next
week with all these tropical systems across the Pacific.

&&

.AVIATION /00Z Sunday through Monday/...
Issued 523 PM MDT SAT SEP 5 2026

Mainly VFR. Patchy mountain-valley fog and low stratus in the
AM. Scattered showers moving from SW to NE over southwest Idaho
late tonight through Sun morning. Then, numerous showers with
isolated thunderstorms moving into E Oregon Sunday afternoon,
and into SW Idaho by evening. Heavy rain and storm outflows to
30-40 kt possible. Surface winds: variable up to 10 kt, then SW-
NW 5-15 kt with gusts 20-25 kt Sun afternoon. Winds aloft at
10kft MSL: S-SW 10-30 kt.

KBOI...VFR with temporary light rain showers between
Sun/06Z-09Z. Then, a 60% chance of showers and thunderstorms
Sunday late evening. Surface winds: NW 5-10 kt, then variable or
light SE overnight and morning.

&&

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

OR...None.

&&

$$

www.weather.gov/Boise

Interact with us via social media:
www.facebook.com/NWSBoise
www.x.com/NWSBoise

AVIATION.....SH
SHORT TERM...KA
LONG TERM....KA