167
FXUS65 KBOI 161531
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
931 AM MDT Mon Jun 16 2025

.DISCUSSION...A weak shortwave trough is moving through the area
today, with a cold frontal passage this evening. The trough will
provide favorable dynamics in a decently moist environment for a
20% chance of rain showers in southeast Oregon and west-central
Idaho. Isolated thunderstorms will develop in the same area,
though storms are expected to be on the weaker side with outflow
gusts generally in the 30-35 mph range. Models show the
strongest outflows struggling to reach 40 mph. Though with the
cold frontal passage gusts will be elevated anyways, with
widespread gusts around 25 mph. Recent high-resolution model
runs have more confidence in showers moving into the Treasure
Valley this evening after they initiate over the Owyhees.
Precipitation clears tonight as the trough and front move
eastward, and we enter a period of quieter weather before the
cold and wet deep upper low pressure system this weekend.

&&

.AVIATION...VFR. Scattered showers and isolated thunderstorms this
afternoon, mainly across the north - including near KBKE/KMYL. Gusty
winds to 35 kt with the storms.  A cold front moves through SE OR
late this aft and SW ID this eve. Surface winds: variable less than
10kt, becoming W-NW 10-20 kt after 18Z, higher gusts near KTWF/KJER.
Gusts to 30 kt behind the cold front. Winds aloft at 10kft MSL: W-SW
5-15 kt.

KBOI...VFR. Slight chance (less than 15 percent) of a shower or
thunderstorm after 21Z. SE winds less than 10 kt, shifting to
NW 5- 12 kt after 16z. A cold front will briefly increase NW
winds to 10- 20 kt with gusts 20-30 kt between 17/01z-04z.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday night...Mid and high
level moisture is streaming across Oregon and Idaho this
morning, attributed to prevailing warm, southwest flow aloft. A
weak Pacific trough is progged to move onshore late this
morning and afternoon, and will bring a weak cold front through
the forecast area by late this afternoon and evening. The
trough will combine with daytime heating to promote afternoon
instability, initiating convection ahead of/along this cold
front. The best chance (15-30%) of showers and thunderstorms
will be over east Oregon and the higher terrain of SW Idaho,
with lower chances (5-10%) near the ID-NV border. Storm outflows
around 30-35 mph are possible. As the cold front sweeps the
area from NW to SE this eve, it will generate a period of wind
gusts to 25-40 mph. Model guidance suggests the highest gusts
will be in east-central Oregon and the Treasure Valley as the
cold front funnels through the western Snake Plain. Temperatures
will become slightly cooler on Tuesday compared to Monday in
the wake of the front, but will quickly warm Wednesday as
ridging returns. Temperatures will remain 5 to 10 degrees above
normal today through Wednesday.

LONG TERM...Thursday through Monday...Southwest flow will re-
develop Thursday and Friday as a prominent Gulf of Alaska
trough moves south along the Pacific Northwest coast. Moisture
and instability ahead of the trough will begin to trigger
convection Thursday evening into Friday across portions of
northeast Oregon and west-central Idaho. The trough and
accompanying cold front is expected to arrive later Friday,
lowering daytime temperatures by several degrees from Thursday
and provoking stronger wind gusts across the area. The cold
core of the low will then move overhead Saturday, continuing the
gusty winds and increasing the probability of showers and
thunderstorms (15-35% for southern areas, 40-60% for northern
areas). Daytime temperatures are forecast to drop an additional
15 to 20 degrees on Saturday with the trough passage. Ensemble
guidance brings snow levels down to 6k-8k feet MSL during this
time, which could result in light snow on the high terrain. A
chance of showers and thunderstorms will continue into Sunday
for northern areas as the main trough heads toward the east-
northeast. Wind speeds should decrease as the upper level
support becomes less organized.

&&

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

&&

$$

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