481
FXUS65 KBOI 232039
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
239 PM MDT Sat Aug 23 2025

.SHORT TERM...Tonight through Monday night...The ridge of high
pressure build today, with very hot temperatures observed
already across the region. Highs today will climb into the
triple digits across lower elevation valleys. Smoke will
continue to settle each night, with light winds keeping the
smoke stagnant in valleys, bringing hazy skies and reduced
visibility until Monday. Isolated virga showers and
thunderstorms will continue to push into southeast Oregon and
near the ID-NV border this afternoon. Tomorrow will see showers
and thunderstorms pushing slightly further north, but still
isolated overall in coverage. Instability has seemed to come
down slightly in recent model runs, likely due to widespread
cloud cover tonight and tomorrow. However, there still looks
like enough to produce isolated thunderstorms across the
southern portions of our region.

Nocturnal convection, primarily in southeast Oregon south of
Highway 20, will continue Sunday night into Monday night, but
coverage will likely still be isolated. Precipitation totals
will be near a quarter of an inch in the heaviest showers, with
highest probability of measurable precipitation near the NV
border.

.LONG TERM...Tuesday through Saturday...Monsoonal moisture will make
itself known throughout the coming week. High pressure aloft
centered over the Four Corners will keep moisture streaming into our
area with southerly flow aloft. This moisture will allow for daily
chances of showers and afternoon thunderstorms across the majority
of Southwest Idaho and Eastern Oregon. With ample moisture streaming
in, PWATs will increase through the week with ensemble mean values
around and even greater than an inch; These PWATs are near the 95th
percentile climatological value. That being said, heavy rain
and possible flash flooding (especially over burn scars) are a
concern throughout the coming week. By Friday, A low amplitude
ridge may set in across our area, limiting chances of showers
and thunderstorms to the higher terrain in Southwest Idaho.
These chances will decrease further by Saturday with just a
slight chance near the Nevada border south of the Magic Valley.
Deterministic and model ensembles show a upper-level closed low
digging down from the Gulf of Alaska late in the work week. This
could cool us down a little bit temperature wise, but given
timing and strength disagreement in guidance, this is resulting
in more uncertainty in temperatures to end the work week. As of
now, it is looking like temperatures will be right around normal
through the long term period.

&&

.AVIATION...Areas of MVFR/IFR due to wildfire smoke in w-central
Idaho, especially near KMYL, resulting in reduced visibility and mtn
obscuration. Smoke layers across E-Oregon and SW-Idaho. Virga
showers in SE-Oregon could produce localized outflows of 40kt this
afternoon. High density altitude this afternoon due to hot
temperatures. Surface winds: Variable up to 12kt. Winds aloft at
10kft MSL: Variable 5-15 kt.

KBOI...VFR. Smoke layers aloft. Surface winds: NW 5-10kt,
becoming light and variable after sunset.

&&

.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

SHORT TERM...SA
LONG TERM....NF
AVIATION.....NF