665
FXUS65 KBOI 121004
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
404 AM MDT Wed Mar 12 2025

.SHORT TERM...Today through Friday night...A deep trough off the
West coast will gradually track inland over the next 48 hours,
increasing the chance for precipitation and bringing cooler
temperatures to the region. Showers will develop today across
SE Oregon and w-central Idaho, focusing north of a Burns- Boise-
Fairfield line through mid-late afternoon. Seeing marginal
convective parameters across SE Oregon this afternoon, mainly
northern Harney and Malheur Counties, where the probability of
thunder peaks at 10-15%. Precipitation in the mountains will
continue through Thursday while the chance for showers increases
at lower elevations with the passage of a cold front overnight.
Snow levels will reach 5500-6500 feet ahead of the front
tonight, dropping to 3-4kft MSL by Thursday afternoon. Mountain
valleys could pick up to 2 inches through Thursday afternoon,
with 3 to 8 inches above 6kft, and 8 to 12 above 7kft. The
chance for rain, snow and graupel showers continues on Thursday
as the cold core of the trough passes overhead. A break in the
precipitation Thursday night into Friday will be followed by
another round of rain and snow as the next wave pushes onshore.
While weaker than its predecessor, snow levels will be lower
with this system (3-4kft MSL) which will translate to light
accumulation across mtn valleys and possibly lower valleys
Saturday morning. Winds will be gusty today as flow aloft mixes
to the surface, mostly impacting SE Oregon and higher terrain of
SW Idaho with 30-45 mph gusts. At or above normal temperatures
today, will drop to 5-10 degrees below normal for Thur/Fri.

.LONG TERM...Saturday through Wednesday...A progressive pattern
continues through the extended period. The e-central Oregon and
w-central Idaho mountains will keep a 60%+ chance of rain/snow
into next week, while lower elevations catch a brief break late
Sat/Sun under a slightly more stable SW flow aloft. Snow will
impact mtn valleys Saturday night through late Sunday morning
with accumulations of 2 to 4 inches before rising snow levels
and temperatures push accumulations mostly above 6000 feet
Sunday afternoon. An upper trough moves into the interior NW on
Monday, dragging a cold front across the region. This will cut
off the bulk of the precipitation while lowering snow levels to
3500-4500ft MSL. Showers under the trough on Tuesday will give
way to drier conditions Tuesday night and Wednesday as a
shortwave ridge builds onshore. Temperatures remain below normal
in the mtns through the period, while lower elevations fluctuate
between +/-5 degrees of normal.

&&

.AVIATION...MVFR and local IFR ceilings will develop across the
e-central Oregon and w-central Idaho mountains by afternoon.
Ceilings will obscure mtns. VFR in lower valleys with periods of
mid-level ceilings today. Mtns remain MVFR-IFR overnight with
lower MVFR conditions possible in s-central Idaho (KTWF/KJER)
Thursday morning. Surface winds: 5 to 15 kt, becoming 10-20 kt
after 18Z with gusts to 30-40 kt across higher terrain. Winds
aloft at 10kft MSL: SW 30-45 kt.

KBOI...VFR with SE surface winds today.

&&

.HYDROLOGY...The flood risk remains elevated across the region
due to snowmelt and forecast precipitation. Flood Warnings for
minor flooding remain in effect on the Malheur River near Vale
and the Owyhee River below Owyhee Dam due to ongoing snowmelt
mitigation. Releases from reservoirs on the Malheur River have
been reduced which have lowered the river below flood stage
early this morning. However, precipitation over the next several
days is forecast to return the river above flood stage, so for
now will keep the Warning for the Malheur at Vale in place.
Releases from the Owyhee Reservoir have the river fluctuating
around minor flood stage so that Warning will remain in place as
well.

Other rivers that could reach flood stage later in the week
include the Silvies River near Burns and the Weiser River near
Weiser.

&&

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

&&

$$

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SHORT TERM...DG
LONG TERM....DG
AVIATION.....DG
HYDROLOGY....DG