606
FXUS65 KBOI 222059
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
259 PM MDT Fri Aug 22 2025

.SHORT TERM...Tonight through Sunday night...A Four Corners high
will briefly extend northwards on Saturday, acting to further
warm tempertures. Lower elevations will see highs approach 100,
with mtn valleys near 90. Wildfire smoke is expected to thicken
over the w-central Idaho mtns, e-central Oregon and the lower
Snake Plain which could inhibit warming, probably more so in the
w-central ID mtn valleys where it is thickest. Mid level
moisture will begin to increase Saturday afternoon across
southern regions as the ridge axis lifts northward. This will
increase the chance of thunderstorms to 10-15% across Harney
County in the late afternoon/evening. Dry near surface
conditions will support the potential for gusty outflow winds
from the high-base development (~15kft MSL). Saturday night will
see more clouds and a low chance of showers along the northern
NV border as moisture continues to increase aloft. Precipitable
water values push past the 90th percentile values for much of
the area. Most sites stay dry on Sunday with a 15-20% chance of
thunderstorms developing in the afternoon/evening across SE
Oregon and along the ID/NV border where there is enough surface
heating/instability to tap into the moisture aloft. Sunday is
not as hot thanks to cloud cover and slightly cooler
temperatures aloft.

.LONG TERM...Monday through Friday...Monsoon is the word of the
week this coming week. High pressure aloft will be centered
over the Four Corners region, shuttling mid-level moisture over
our area. This moisture, paired with peak-heating destabilizing
our atmosphere, will allow for daily chances of afternoon
showers/thunderstorms. Ensemble means have PWAT values of around
and inch, which would place it near the 95th percentile. By
Tuesday, some individual ensemble members show PWATs of 1.3-1.4
inches, which would be above the climatological 99th percentile.
With ample moisture available, storms will be able to produce
heavy rain in addition to gusty outflows. This is increasing
flash flood concerns, especially over burn scars. Temperatures
will be 5-10 degrees above normal on Monday and Tuesday. On
Wednesday, temperatures will cool to near normal and show little
daily variations through Friday.

&&

.AVIATION...Areas of MVFR/IFR due to wildfire smoke in w-central
Idaho, especially near KMYL, resulting in mtn obscuration. Smoke
expanding into SW Idaho through the afternoon. Surface winds:
Variable under 12 kt this afternoon/evening. Winds aloft at 10kft:
Variable 5-15 kt.

KBOI...VFR. Smoke increasing through the evening, which may lower
visibility. Surface winds: light and variable, becoming NW up to 10
kt by Fri/22z.

Weekend Outlook...Mainly VFR. Visibility reductions and mtn
obscuration in W-Central Idaho due to wildfire smoke. A 10-15%
chance of showers/thunderstorms in SE Oregon Saturday PM, then 30-
50% chance of storms near the NV border Sunday PM. Variable 5-15 kt
surface winds, except gusty/erratic winds 35-45 kt near
thunderstorms.

&&


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

&&

$$

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SHORT TERM...DG
LONG TERM....NF
AVIATION.....NF