121
FXUS65 KBOI 300244
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
844 PM MDT Fri Aug 29 2025

.DISCUSSION...Similar to yesterday, isolated severe thunderstorms
(1-inch sized hail), occurred this afternoon, this time in
southwestern Baker County/OR and in Idaho between Fairfield
and Gooding. Heavy rain also fell with these storms. Precipitable
water at Boise this evening was .60 inch, vs .59 inch yesterday.
Saturday`s PW is forecast to be lower, so thunderstorm chances
will be less than today (10% at most) and any storms that do
form should have less rain. Little if any chance of thunderstorms
for several more days afterward. Also, an upper ridge over our
area will be stronger Saturday, so several degrees warmer than
today. Warming will continue through Labor Day and stay hot
through Wednesday before gradually cooling. Wildfire smoke will
be the main weather "feature" through Saturday, worst Saturday
morning then improving some in the afternoon. Current forecast
is on track.

&&

.AVIATION...Generally VFR. Smoke layers degrading visibility at
times. A 10% chance of showers/thunderstorms Saturday afternoon
near KBKE and KMYL. Surface winds: variable up to 10 kt. Winds
aloft at 10kft MSL: variable 5-10 kt.

KBOI...VFR. Smoke layers degrading visibility, with some
improvement Saturday afternoon. Surface winds: SE 3 to 8 kt.

Sunday Outlook...VFR, except smoke layers degrading visibility
at times. Surface winds S to E 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...Lingering moisture
is supporting afternoon and evening thunderstorms today. Storms
are initiating along the Nevada border, and will develop near
Baker County and in S-Central Idaho. Enough moisture exists for
storms to produce moderate to locally heavy rainfall, as well as
small hail. With the lower atmosphere drying out, outflow winds
are also a concern, with gusts up to 45 mph possible. Outflow
gusts could persist even into areas that don`t see any storms,
with some high resolution models resolving an outflow moving
from Baker County down into the Treasure Valley. This morning`s
sounding showed some instability present at Boise, so there is
potential for cumulus buildups even over the Central ID
Mountains.

Smoke is still present, mostly aloft, from the Emigrant fire.
Overnight it could settle near the surface, making for a
potentially smoky Saturday morning. Saturday and Sunday, an
upper ridge amplifies and the area begins properly drying out as
stable conditions set in. Temperature will warm several degrees
each day through Sunday, putting lower valleys in the lower 90s
and mountains in the mid 80s this weekend. As the upper flow
becomes more southerly along the ridge axis, smoke could be
deflected north and west.

LONG TERM...Monday through Friday...Low pressure off the PacNW
coast and high pressure over the inland west remain stationary
through the long term. Southerly flow will pull weak monsoon
moisture northward Tuesday through Friday, enough for some
models to show a 10% chance of precipitation, but others remain
dry even during this period. That being said, there is
significant uncertainty in the details even though the overall
pattern hasn`t changed much. A few shortwaves seem to pass
through at different times among leading models, which would
provide favorable dynamics for precipitation. The most likely
spots to see precipitation are SE OR and high terrain in ID.
Temperatures will remain around 5 degrees above normal under
the ridge.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....SH
SHORT TERM...JM
LONG TERM....JM