099
FXUS65 KBOI 121609
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1009 AM MDT Wed Mar 12 2025

.DISCUSSION...A warm front under strong southwest flow aloft
will bring showers to the area today, mainly focused over the
mountains and the upper Weiser River Basin. A cold front will
track across eastern OR late this afternoon and into southwest
ID late tonight into Thu morning. There is enough instability
for a 10-20 percent chance of thunderstorms along the front late
tonight. Precipitation amounts with this system continue to
trend downward from previous forecasts. After the front moves
through, showers generally linger over the west central and
Boise mountains through midday Thu. Scattered graupel showers
develop during the heating of the day on Thu. No updates to the
forecast.

&&

.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 tonight with lower MVFR
conditions possible in s-central Idaho (KTWF/KJER) Thursday morning.
Surface winds: SE-SW 5 to 15 kt increasing to 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 around 10 kt today.

&&

.PREV DISCUSSION...
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.

&&

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

&&

$$

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DISCUSSION...KA
AVIATION.....TL
SHORT TERM...DG
LONG TERM....DG