519
FXUS65 KBOI 172106
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
206 PM MST Mon Nov 17 2025

.SHORT TERM...Tonight through Wednesday night...A weak ridge
will build back into the region this evening, bringing drying
conditions and helping the showers across the area to taper off.
Two cut off lows will skirt our region today and tomorrow, with
one diving down to the south and another moving north. This
situates us in the deformation zone between the lows, with
mostly dry conditions. Warm and moist southwest flow will
continue to bring intermittent cloud cover tomorrow over the
region, with clearing overnight allowing for widespread fog
formation in area valleys on Tuesday and Wednesday morning.
There`s medium confidence in dense fog formation resulting in
visibilities below 1/4 mile in lower elevation valleys tomorrow.
A weak cold front will move into the region on Wednesday,
bringing a 20-40% chance of mountain snow above 5000-6000 feet
with valley rain in Baker County and the West Central Mountains.
Temperatures will continue to cool throughout the short term
period, but still be about 5-10 degrees above normal, with
daytime highs in the Boise area in the mid to upper 50s through
Wednesday.

.LONG TERM...Thursday through Monday...A very similar pattern to
recent days will continue in the extended. An upper level trough
will split at it approaches the coast on Thursday. The southern
portion will develop into a cutoff low and move south into
California, resulting in only a 20-40% chance of showers across our
area. High pressure will then build overhead through the weekend. A
temperature inversion may develop under stable conditions, and low
clouds/fog may become persistent in the lower elevations if enough
moisture gets trapped under the inversion. Temperatures are expected
to average slightly above normal across the area, but if low clouds
and fog do develop, that would reduce high temperatures.

Moisture is expected to move over top of the ridge late in the
weekend into early next week. Ensembles favor the ridge to be strong
enough to keep the moisture to our north through Sunday, resulting
in lower precipitation chances than previous forecasts over the
weekend. On Monday, an upper level trough approaching the coast will
bring a 30-60% chance of precipitation, with the highest chances in
the northern mountains. Snow levels around 4500-6000 feet will keep
precipitation as rain in the lower elevations, with snow
accumulations limited to the mountains.

&&

.AVIATION...Mainly VFR through early this evening, although pockets
of MVFR/IFR from low clouds will persist across southeast OR and in
the southwest ID mountains. Mountains obscured. Partial clearing and
light winds will allow areas of LIFR fog to develop in the valleys
tonight into Tuesday morning, possibly lingering into the afternoon.
Surface winds: variable 10kt or less. Winds aloft at 10kft MSL: S-SW
5-15kt.

KBOI...VFR prevailing through the evening with ceilings above 5000
ft AGL. Around a 20-30% chance of LIFR low clouds/fog developing
Tuesday AM, with higher chances of fog to the west near KEUL.
Surface winds SE 5 kt or less.

&&

.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....ST
AVIATION.....ST