Boise, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

302
FXUS65 KBOI 222113
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
213 PM MST Mon Dec 22 2025

.SHORT TERM...Tonight through Wednesday night...This afternoon
the frontal band that brought heavy rain Sunday still extended
roughly through Yellowstone- Sun Valley- Winnemucca/NV and still
has light rain showers along it. The front will shift northward
as a warm front again tonight through Tuesday, due to
strengthening SSW-ly flow aloft, with pcpn also increasing under
an intensifying atmospheric river (AR) from the Pacific subtropics.
By late Tuesday the front will be completely north of our CWA
and continuing to move north, allowing our CWA to dry out from
the south, while a cold front along the coast begins to move
inland. Our CWA will then be in the "warm sector" south of the
warm front and east of the cold front, with temps rising into
the 50s in the southern CWA valleys. At the same time, southeast-
southwest surface winds will become breezy in our southern
zones, and increase even further Wednesday morning ahead of
the approaching cold front, especially in eastern OR. Speeds
may reach Advisory criteria Wednesday, but not to the magnitude
of last Tuesday`s wind storm. The cold front will bring more
pcpn into our CWA late Wednesday, and especially Wednesday
night when it passes through ID. Heaviest pcpn is again aimed
at the Boise Mountains but all areas should have a period of
moderate to heavy rain as the front passes. With SW-ly winds
aloft behind the front temps will lower only a few degrees,
while snow level lowers only to around 5000 feet north to 7000
feet south by Christmas morning.

.LONG TERM...Thursday through Monday...A deep upper low off the
coast of Northern California is expected to slowly steer inland
Thursday, continuing precipitation over the area. Gusty ridgetop
winds and lower snow levels are expected Thursday through
Saturday. Temperatures Thursday will still be 10-15 degrees
above normal, cooling down to 5 degrees above normal by Saturday
as the low steers across the region as a shortwave trough.
Precipitation is likely for much of the area as snow levels
Thursday drop from 5-6 kft MSL to 3-4 kft MSL by Friday evening.
While this begins to hint at wintry precipitation for lower
elevations by Saturday, snow levels drop to valley floors as the
trough and precipitation exit east and taper off. Lower
elevation valleys will likely see rain Friday, while mountains
will see snow through Saturday early morning. Otherwise, mostly
dry conditions Saturday through Monday. Saturday night through
Monday, temps hold steady at just above normal for this time of
year as most of the guidance suggests a ridge building overhead
off the Pacific. The ridge and increasing heights aloft with
temps holding steady shows some early signs of a potential
inversion. If any inversion does form, it may shortlived as the
extended forecast shows a return to unsettled weather next
week.

&&

.AVIATION...Widespread OVC cloud coverage this afternoon/early
evening, with some IFR-LIFR ceilings hanging over Upper Treasure
Valley (KEUL and KONO) and mountain areas. Precipitation with
MVFR/IFR cloud ceilings expected to return mainly over SW/W-
Central ID this evening. Snow levels 6-8 kft MSL. Surface winds:
SE-SW 5- 15 kt. Winds aloft at 10kft MSL: W-SW 30-50kt.

KBOI...Mainly VFR this afternoon/early evening. Low IFR-LIFR
stratus lingering in vicinity and foothills this afternoon.
Surface winds SE 7-12 kt.

&&

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

&&

$$

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SHORT TERM...LC
LONG TERM....JY
AVIATION.....JY