628
FXUS65 KBOI 170832
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
232 AM MDT Sat May 17 2025

.SHORT TERM...Today through Monday night...A strong upper level
trough making landfall along the coast this morning will race
east and pass over the area today into this evening. There will
be sufficient moisture and instability for numerous showers and
isolated to scattered thunderstorms. Thunderstorms are possible
in southeast Oregon and western Owyhee County this morning, then
remaining there and spreading east and north into much of SW ID
this afternoon and early evening. Storms will be capable of
small hail, wind gusts to 40 mph, and of course lightning. A
cold front will move into eastern Oregon late this afternoon and
pass through the remainder of the area tonight. Following this,
winds will become strong late tonight through Sunday afternoon,
and a wind advisory has been issued for portions of southwest
ID for Sunday (generally southeast of Boise). Temperatures will
be held down 10-15 degrees below normal today by the clouds and
precipitation, and tomorrow will be even a touch cooler in most
areas behind the cold front. Showers and storms will be favored
Sunday over the Idaho side, but a few showers will remain in
eastern Oregon, especially over the higher terrain. Sunday
night, the precipitation will depart to the east. Apart from a
slight chance of showers across the higher terrain of the north,
Monday and Monday night will be dry, and Monday`s highs will be
about 10 degrees warmer than Sunday. Accumulating snow today and
tomorrow will be confined to elevations above around 6500 ft
MSL, with 6 to 9 inches possible on the highest peaks.

.LONG TERM...Tuesday through Saturday... A dry and seasonable period
will take shape through much of the week, with a gradual warming
trend. There is good agreement that a more zonal pattern will settle
over the region, with embedded, generally dry, atmospheric waves
working through. The deepest of these waves is on tap for late in
the week, introducing a low chance (15%) of showers by late Friday
into Saturday for the central Idaho mountains. The warmest temps
will likely be on Friday ahead of this wave, with values 5-10
degrees above normal.

&&

.AVIATION...Generally VFR, except MVFR possible in showers and
thunderstorms. Storms to develop before 12Z in SE Oregon, and
becoming numerous area-wide after 15Z. 20-30% chance of
thunderstorms, with gusty outflow winds possible. Mountains
obscured. Surface winds: SE-E 5-10kt becoming NW 10-15 gusts to 20
kt as showers move east. Strong outflow of variable direction and
gusts to 30 kts possible in thunderstorms. Winds aloft at 10kft MSL:
W-SW 10-20 kt becoming NW 10-25 kt after 20Z.

KBOI...Generally VFR. Rain showers move in after 15Z with a 20%
chance of thunderstorms after 16Z. MVFR possible (30% chance) from
low ceilings in showers/thunderstorms. Mountains obscured. Surface
winds: E-SE 8-15 kt, becoming NW after 22Z. Gusty outflow winds to
30 kt possible in/around thunderstorms.

Sunday Outlook... VFR with possible MVFR in showers. Mountains
obscured through early afternoon. Precipitation moves out from west
to east by the afternoon, with improving conditions.  Surface wind
increasing to NW 15-30 kt gusting up to 25-40 kt especially in the
Snake Plain. Snow levels falling to 5000-7000 ft MSL Sunday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory from 6 AM to 6 PM MDT Sunday IDZ014-016-028-030.
OR...None.

&&

$$

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SHORT TERM...SP
LONG TERM....MC
AVIATION.....MC