095
FXUS65 KBOI 011559
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
959 AM MDT Mon Sep 1 2025

.DISCUSSION...
A strong ridge remains in place across the Pacific Northwest
with the ridge axis positioned just to the west. This setup will
keep temperatures today and Tuesday well above normal and near
record levels. Highs in the Treasure Valley are expected to
reach around 100 degrees, which is roughly 15 degrees warmer
than average for early September.

Satellite imagery shows a widespread cumulus field across much
of the area this morning, with the deepest development noted
over Owyhee County. The latest high resolution models continue
to focus on this area, along with portions of Malheur County,
for possible thunderstorm development early this afternoon.
Based on the current satellite trends, this region still appears
to have the best potential for storms, with chances near 15
percent. A few thunderstorms are also possible across parts of
the central Idaho mountains later today.

Any Storms that do form will be high based and capable of
producing gusty outflow winds up to 40 MPH with little rainfall.
This scenario is already reflected in the current forecast, so
no updates are needed.

&&

.AVIATION...VFR. Smoke Layers aloft through 20kft MSL. High density
altitude this afternoon due to hot temps. A 10-20% chance of virga
showers/thunderstorms in E-Oregon and far SW-Idaho from Mon/18z to
Tue/03z. Surface Winds: S-E 5-15 kt with localized gusts to 25 kt
from KGNG to KBKE this morning. Winds aloft at 10kft MSL: S 10-20kt.

KBOI...VFR. Smoke Layers aloft. Surface winds: E-SE 7-12 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday night...High pressure
aloft will keep summer like temperatures over the region as we
enter the first month of fall. The next couple of days will see
highs flirt with 100 degrees across the lower Snake Plain while
mtn valleys approach 90. This will put some sites close to
records today and especially Tuesday which looks to be the
hottest day. Otherwise will keep an eye on elevated moisture
that has maintained just enough of a presence to fuel afternoon
showers and thunderstorms the last couple of days. Today the
focus is across southern Malheur and Owyhee counties. The FV3
(which typically runs hot with shower/storm development) has
been doing well and is one of a couple model solutions to show
showers entering the lower Treasure Valley this afternoon in the
vicinity of Caldwell. All this said, have beefed up
precipitation chances (15-20%) in these areas. Tuesday and
Wednesday will see a minor upper low lift north through Oregon.
This system will increase shower and thunderstorm coverage
across SE Oregon and far SW Idaho Tuesday and Tuesday night.
Current model output shows the upper ridge axis holding strong
which keeps precipitation from extending further eastward
through the day Wednesday. Wednesday is hot, but a few degrees
off of Tuesday`s peak.

LONG TERM...Thursday through Monday...The upper ridge starts to
weaken on Thursday, and this trend looks likely to continue
through the weekend as energy pushes in from the coast.
Precipitation coverage will increase starting Friday, with a
broad 20-40% chance of daytime showers and thunderstorms
through Monday. Precipitable water values could top out over an
inch Fri/Sat, introducing the potential for heavy rain.
Temperatures gradually cool down to near normal by Sun/Mon.

&&

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

&&

$$

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