396
FXUS65 KBOI 081108
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
508 AM MDT Tue Sep 8 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...

- Warmer and drier days through most of Thursday.

- Cold front and gusty winds Thursday evening, followed by
  breezy and cooler weather Friday.

- Stronger cold front late Saturday and Saturday evening with
  gusty winds, showers, and thunderstorms, then much cooler
  Sunday.

- Warming and drying again Monday and Tuesday.

&&

.SHORT TERM /Through Thursday Night/...
Issued 212 AM MDT TUE SEP 8 2026
Weak upper low in northern Idaho will exit into Montana this
morning, resulting in sunny, warmer, and drier days in our CWA
through most of Thursday. Nights will stay cool. High temps
will reach the 80s in the southern valleys Wednesday and
especially Thursday. Tropical moisture will surge northward
through CA and NV but not as far north as our CWA. An upper
trough digging southward from western Canada will push a dry
surface cold front through our CWA late Thursday and Thursday
night. The front will bring gusty northwest winds and end the
warm weather.

&&

.LONG TERM /Friday through Tuesday/...
Issued 212 AM MDT TUE SEP 8 2026
Friday looks sunny, windy, and cooler behind Thursday night`s
cold front, but Saturday looks warmer again as upper flow backs
to southwesterly. The southwest flow will be ahead of a deep,
cold upper low moving southward from the BC coast to just off
the WA and OR coast. That low is forecast to move rapidly inland
across OR Saturday with a strong surface cold front, gusty winds
at least 30 mph (partly due to the speed of the incoming low),
and a chance of showers and thunderstorms, then much cooler
Sunday. Monday will already be warming and drying again as the
upper low moves all the way to North Dakota, and Tuesday looks
sunny and warmer still under building high pressure aloft over
the Great Basin.

&&

.AVIATION /12Z Tuesday through Wednesday/...
Issued 504 AM MDT TUE SEP 8 2026
VFR. Patchy mountain valley stratus/fog early this morning.
Surface winds: variable less than 10 kt. Winds aloft at 10kft
MSL: W around 15 kt.

KBOI...VFR and mostly clear. Surface winds: light SE, becoming
NW 5-10 kt after Tue/17Z, then light SE after Wed/03Z.

&&

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

OR...None.

&&

$$

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AVIATION.....LC
SHORT TERM...LC
LONG TERM....LC