634
FXUS65 KBOI 140259
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
859 PM MDT Mon Oct 13 2025

.DISCUSSION...At 00Z the Pacific upper low 36N/125W was slightly
west of model forecasts, suggesting it will turn inland a little
later and farther south than models predict for Tuesday. If that
happens, NAM would be the best model choice. But NAM has problems
too, as it shows pcpn moving rapidly into southwest Idaho toward
morning, whereas other models hold it back in Nevada.  Current
forecast includes those other models and brings only light rain
into southwest ID Tuesday morning, and waits until Wednesday to
bring heavier pcpn into southern ID from east to west, as
moisture wraps around the low which should then be over Utah.
Even with model spread larger than usual, current forecast is
a good fit and no updates will be made at this time.

&&

.AVIATION...Generally VFR overnight with local mountain
obscuration from low-VFR ceilings. Scattered showers on Tuesday
will bring low-VFR and local MVFR ceilings and obscure mountains.
Snow levels rising to between 7500-8500 feet MSL. Surface winds:
Variable 5-15 kt. Winds aloft at 10kft MSL: variable 5-15 kt.

KBOI...VFR. Rain showers possible Tuesday. Light northwest surface
overnight.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...Low clouds are
persisting in area valleys today, with a few showers over
northern Malheur County and Baker County this afternoon. A
closed low will move over central California tomorrow,
bringing wet and cool conditions to the region through Thursday
morning. Warm southerly winds as the low shifts east will
increase temperatures a few degrees tomorrow and bring
instability to higher elevations. This will allow for a 10-20%
chance of afternoon thunderstorms, primarily in high terrain in
Central Idaho. Accumulations from the precipitation tonight and
tomorrow will be minimal, generally less than 0.10-0.20 inches
of rain with up to 2 inches of snow anticipated above 7000 feet
MSL.

Another push of moisture will move through Tuesday night through
Wednesday morning as the closed low moves north and east across
the Nevada-Utah border, bringing a band of heavy rain through
the region from east to west. Rain accumulations from this band
of precipitation will be around 0.20-0.50 inches of rain by
Wednesday night, with cooler temperatures. Snow levels will dip
down to 6500-7500 feet by Wednesday evening, bringing another
1-3 inches of snow in the heaviest showers to ridgetops.

LONG TERM...Thursday through Monday...As an upper level low
pressure system moves east, high pressure builds in the northern
Pacific. This favors general northwesterly flow over the region,
with enough moisture to keep things unsettled and colder air to
hold temperatures steady. For the most part, this means Thursday
through early Sunday will have persistent scattered clouds, a
less than 10% chance of precipitation, and temps about normal.
By Sunday, a deep trough approaches the coast, with a quick
moving pocket of moisture bringing precip chances of 40-50%,
dropping snow levels to 5 kft MSL, and dropping temps to 10
degrees below normal. The higher precip chances 7 days out
highlight the decent model agreement among deterministic
models. Ensembles, however, are a little less discrete, hinting
at some uncertainty in the overall synoptic pattern.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
VFR. Rain showers possible Tuesday. Light northwest surface
overnight
&&

$$

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DISCUSSION...LC
AVIATION.....DG
SHORT TERM...SA
LONG TERM....JM