566
FXUS65 KBOI 270255
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
855 PM MDT Sun Oct 26 2025
.DISCUSSION...The last part of this Pacific storm system will
continue to move across the area tonight, bringing widespread
light precipitation. Overall, precipitation accumulations have
been minimal across southeast Oregon, with most sites seeing
less than 0.05 inch total so far. The latest high res QPF has
lowered about 15 percent over earlier runs, thus we have lowered
QPF in line with these latest trends.
The cold front reached Burns, Oregon around 8 PM and should
reach Baker City around 9 PM and Boise/McCall around midnight
tonight. Brief moderate rainfall along with wind gusts up to 30
MPH are possible with the frontal passage. Snow level looks to
be around 5000 feet this evening and could lower to near 4000
feet by the time precipitation ends early Monday morning.
Showers will continue along Nevada and the Western Magic Valley
through mid Monday morning. No significant changes to snow
amounts are anticipated, with the Long Valley seeing about 1
inch and the mountains above 6000 feet seeing 3 to 6 inches
tonight. The update will be out shortly.
&&
.AVIATION...Rain/snow across E Oregon and SW Idaho, creating low
VFR/MVFR in rain, IFR/LIFR in mtn snow. Local IFR at KTWF/KJER. Mtns
obscured. Snow levels: 4500-5500 ft MSL lowering to around 3000-4500
ft overnight. Improving conditions Monday morning. Surface winds: SW-
SE 5-15 kt, becoming NW-W 5-15 kt with areas of 20-30 kt gusts
overnight. Winds aloft at 10kft MSL: W to NW 20-35 kt.
KBOI...Rain showers will create periods of MVFR ceilings and
foothill obscuration. Showers ending around 27/08z. Lower ceilings
will lift/dissipate after precip ends. Surface winds: SE 5-15 kt,
then W-NW 5-12 kt after precip ends. Periods of 15-25 kt gusts
between 27/08z-12z.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday night...An upper
shortwave trough crossing Oregon this afternoon will increase
precipitation coverage across the region as it moves eastward
this evening. The best chance for rain and mtn snow falls ahead
of an accompanying front. Modeled timing of the frontal passage
remains consistent, bringing it through SE Oregon late this
evening (2000-2400MT), and SW Idaho overnight (2300-0300MT).
The lightning threat remains low (10-15%) across e-central
Oregon and the w-central Idaho mtns where timing would be most
favorable. Event without lightning, stronger showers along the
front could bring moderate rain/snow rates. Snow levels will
drop to mtn valley floors this evening allowing for a mixed
precipitation type, though temperatures will initially limit
accumulation. The higher precipitation rates along the front
will bring the best chance for accumulation and a quick inch is
possible in interior mtn valleys, to include Cascade and
McCall. Above 6kft MSL amounts will total 3-5 inches through
sunrise Monday. The cold frontal passage will also bring a
period of gusty winds overnight, mostly contained in the 25-40
mph range. Locally higher gusts to 45 mph are possible in the
mtns.
A 20-30% chance of showers continues in the e-central Oregon
and w-central Idaho mtns on Monday under northwest flow aloft.
Monday night through Tuesday night is dry as upper ridging
builds in from the coast. Monday night will be the coldest with
freezing temperatures likely across all zones, including a
possible hard freeze for many sites in the Snake Plain.
Temperatures through Monday night are 5-10 degrees below normal.
LONG TERM...Wednesday through Sunday...The early part of the
long term will be generally dry with temperatures around
normal. This is due to zonal flow between subtropical high
pressure and a strengthening Alaskan low pressure system. A few
weak shortwaves prevent temps from warming too much during this
period, and bring mild breezes Wednesday. Friday afternoon
clouds increase as very moist tropical moisture is pulled into
the strong flow of the Alaskan low. Most precipitation with this
atmospheric river will impact the PacNW and Canadian West
Coast. However, models show sparse residual moisture bringing
precipitation to northern parts of our forecast area Saturday
night. Sunday is a return to dry weather with a ridge axis
developing over the region as another wet system sets up off in
the NE Pacific.
AVIATION...Widespread light precipitation is still expected to
move north this afternoon, though has been a little slower in
its motion than forecast. Light valley rain and mountain snow
will be augmented by some stronger showers this evening with
moderate rain and snow possible near KBKE and KMYL. Snow levels
are 5-6 kft MSL. Widespread MVFR in the precipitation shield
with IFR-LIFR in snow and low clouds. Surface winds: SE-SW 5-15
kt, becoming W-NW 5-15 kt with gusts to 30 kt around midnight.
Winds aloft at 10kft MSL: SW-W 15- 30kt.
KBOI...Light rain slightly delayed, but still expected this
afternoon through sunset when the precipitation mode becomes
more sporadic/showery. Ceilings could drop to MVFR when the
rain arrives, improving after midnight as the rain dissipates.
Surface winds are SE 5-15 kt, becoming NW 10-15 kt around
midnight.
&&
.PRELIMINARY POINT TEMPS/POPS...
Baker City 28 47 19 48 / 90 0 0 0
Boise 33 48 32 53 / 80 0 0 0
Burns 21 46 16 52 / 70 0 0 0
Caldwell 32 51 29 55 / 80 0 0 0
Fairfield 26 40 12 44 / 90 0 0 0
Idaho City 26 44 18 51 / 90 10 0 0
Jerome 32 42 26 47 / 90 0 0 0
McCall 26 38 15 44 / 100 20 0 0
Mountain Home 31 50 26 54 / 80 0 0 0
Ontario 32 52 27 52 / 90 0 0 0
Rome 27 48 21 56 / 80 0 0 0
Twin Falls 31 42 26 49 / 100 0 0 0
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...JDS
AVIATION.....SH
SHORT TERM...DG
LONG TERM....JM
