Boise, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

964
FXUS65 KBOI 200920
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
320 AM MDT Sun Jul 20 2025

.SHORT TERM...Today through Tuesday night...A dry southwest
flow aloft remains over the area today as an upper trough
develops over the Pacific Northwest. The trough edges closer
tonight, resulting in an increasing chance (up to 50 percent)of
showers across northern areas (mainly from northern Harney
County into Baker County - eastward to the west central ID
mountains) late tonight. The shower chances expand eastward on
Monday as the trough moves closer, but the showers are expected
to remain west and north of Boise. The highest chances (30-60
percent) extend across SE Oregon into the west central ID
mountains. There is also enough instability for a slight chance
(less than 20 percent) of afternoon and evening thunderstorms.
The trough weakens but lingers over the northwest on Tuesday,
but the chances of showers are much lower (less than 20 percent)
and mainly confined to SE Oregon. Winds will be breezy this
afternoon and again Monday afternoon. Temperatures trend cooler
through Monday, followed by warmer temperatures (but still below
normal) on Tuesday. Patchy smoke will continue through tonight,
especially in the vicinity of wildfires. Some improvement is
possible Monday and Tuesday with the cooler temperatures and
chance of showers.

.LONG TERM...Wednesday through Sunday...A weakening upper level
trough is forecast to move west to east across northern Idaho
Wednesday, as a cut off low remains off the coast of northern
CA. Our upper flow will be zonal Thursday, becoming weak
southwesterly Friday, and finally strengthening out of the SW
Saturday and Sunday. Models are in well-above-average agreement
on this pattern. Moisture will increase as the SW flow arrives,
giving us small chances for mainly afternoon and evening
thunderstorms from Thursday through the weekend. This chance is
presently too low to be mentioned in the formatted forecast
products (which require at least a 15% chance). However, we felt
it worth mentioning in this discussion because we believe that
the chance will increase and eventually be high enough to
warrant inclusion in the forecast. Temperatures are forecast to
be within a few degrees of normal through the long term period,
with Thursday and Friday likely the warmest days. Winds are
expected to be typical for this time of year, with the normal
diurnal trends.

&&

.AVIATION...VFR. Patchy smoke layers aloft. Surface winds:
W-NW 5-15 kt. Gusts to 25 kt after 20/18Z along the NV border.

KBOI...VFR. Surface winds: variable around 5 kt, becoming NW
8-12 kt with gusts 15-20 kt after 20/18Z.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Fire Weather Watch from this afternoon through this evening
     IDZ423-426.
OR...None.

&&

$$

www.weather.gov/Boise

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SHORT TERM...BW
LONG TERM....SP
AVIATION.....SP