427
FXUS65 KBOI 291717
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1017 AM MST Sat Nov 29 2025

.DISCUSSION...High clouds are increasing from the northwest
today as the next system moves into the area late this evening.
A back door cold front from Montana and eastern Idaho will bring
cold dry air down Snake Plain today. East-southeast winds will
pick up and increase to 15 to 25 mph this afternoon in the Snake
Plain. Snow showers increase late this evening in eastern OR
and overnight into Sunday morning in southwest ID as a weak
system moves across the area. Cool dry air in the Snake Basin
from east to southeast flow will limit snow amounts to under an
inch due to evaporation in the low levels, while the higher
terrain will generally see 1-3 inches of new snow. No updates.

&&

.AVIATION...Areas of low stratus in E-Oregon and the Magic Valley
resulting in MVFR ceilngs. Becoming VFR with high clouds after
Sat/17z. Snow developing from N to S after Sun/06z resulting in
MVFR/LIFR conditions and mountain obscuration. Snow showers exiting
the area around Sun/18z. Snow levels on valley floors. Surface
winds: E-SE 5-15 kt with localized gusts to 22 kt in the Snake Plain
this afternoon. Winds aloft at 10kft MSL: Variable 5-20 kt,
becoming W-SW 10-25 after Sat/18z.

KBOI...VFR Saturday. Snow showers developing Sunday morning, with a
50% chance of snow at terminal between Sun/8-13z. MVFR/IFR
conditions in snow with foothill obscuration. Accumulations of under
half an inch of snow expected. Surface winds: SE 8-12kt with gusts
up to 20 kt this afternoon.

Sunday Outlook...Snow showers tapering off from N-S Late Sunday
morning through Early Sunday afternoon. Conditions improving to VFR
through the afternoon with decreasing clouds. Surface winds: N-NW 5-
15 kt, with 20-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Monday night...Friday`s cold front
and afternoon wind dried out the air mass, and there is less
fog in the valleys than the previous two nights. The air is
also colder. Snow level will stay near valley floors when the
next upper trough (currently in western BC) comes in tonight.
The trough will spread a dusting to an inch of snow over all
areas overnight, continuing Sunday morning south of the Snake
River in ID, then ending early Sunday afternoon. For the lower
southern valleys this will be the first snowfall of the season.
Snow may briefly cover main roads around sunrise Sunday. Roads
should become wet by mid-morning, with any remaining snow
melting by midday as temps rise through the 30s. Skies will
clear Sunday night. Lingering moisture from the melted snow
will develop patchy fog in the valleys Sunday night and Monday
morning. Higher valleys and basins will keep their new snow
cover and may become very cold Monday morning as heat radiates
off the snow out into space. After skies clear Monday morning,
Monday should be mostly sunny but begin to cloud up from the
north later on as the next upper trough approaches from the
north. A 30 to 60 percent chance of light snow will spread south
into our CWA late Monday night with best chance in the west
central Idaho mountains.

LONG TERM...Tuesday through Saturday...An upper level trough
will move across our area from northwest to southeast on
Tuesday. Moisture will be limited with this system, resulting in
light precipitation amounts. Precipitation chances are 30-50%
in the valleys and 50-80% in the mountains. Snow levels will be
around 2500-3500 feet, resulting in snow in the mountains and a
rain/snow mix in the valleys. With snow levels near valley
floors, there is around a 20% chance of accumulating snow in the
Treasure and Magic valleys. Snow amounts of a couple inches
will be possible in the mountains. This system will also bring
breezy winds and slightly below normal temperatures.

After the trough exits the area on Wednesday, the large-scale
pattern will remain amplified through Friday with a ridge in
the eastern Pacific and trough in the central U.S. As a result,
cool and mostly dry northwesterly flow will keep temperatures
near to slightly below normal with a 20-40% chance of snow in
the mountains. On Saturday, the ridge is favored to weaken,
allowing potential for Pacific moisture to return to the area.
However, how much/when the ridge weakens and how much moisture
remains uncertain. The net result is a 20-60% chance of
rain/snow and an uptick in temperatures, with snow levels
around 4000-6000 feet.

&&

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

&&

$$

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DISCUSSION...KA
AVIATION.....NF
SHORT TERM...LC
LONG TERM....ST