337
FXUS65 KBOI 020244
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
839 PM MDT Sat Nov 1 2025

.DISCUSSION...Current forecast is on track through the coming
week beginning with a weak cold front overnight and Sunday
morning. The front will bring light rain showers to the northern
half of our CWA, but only clouds to the southern half. High temps
Sunday will be about 10 degrees cooler than today`s near record
highs. The supporting upper trough is very shallow and will be
followed by a flat upper ridge and several degrees warming again
Monday.  A series of upper troughs and ridges will come in from
the Pacific the rest of the week, with the strongest ridges and
warmest temps Wednesday and next Sunday, and deepest troughs and
best chances for pcpn (generally rain) Wednesday night and Friday.

&&

.AVIATION...VFR thVFR, becoming cloudy tomorrow morning with a 10%
chance of light rain as a weak front passes. Surface winds SE 5-15
kt tonight becoming NW 5-15 kt after the front passes.is evening,
with drops to MVFR due to low ceilings as a weak cold front moves
through early tomorrow morning from NW to SE. Scattered light rain
accompanies the front with little impact. 20-30 kt of LLWS possible
as front passes. Surface winds: SW 5-15 kt becoming NW 5-15 kt
behind the front. Winds aloft at 10kft MSL: W-SW 25-45 kt.

KBOI...VFR, becoming cloudy tomorrow morning with a 10% chance
of light rain as a weak front passes. Surface winds SE 5-15 kt
tonight becoming NW 5-15 kt after the front passes.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...Expect warm
temperatures this afternoon, with lower valleys seeing highs
near 70 degrees. An area of high pressure is moving east,
which will allow winds to become locally breezy this afternoon,
continuing through Sunday. A Pacific storm system will pass to
our north tonight, bringing light showers primarily to areas
north of a line from Burns, Oregon to Boise to Atlanta, Idaho.
The highest chance for rain will be in the far northern
mountains near McCall and Baker City. The Treasure Valley
might see a sprinkle or two, but any rain there will be
minimal, likely less than one hundredth of an inch. Snow
levels will be very high, holding above 9000 feet through
Sunday morning before slowly lowering to around 6500 feet
Sunday afternoon in the northern mountains. Total rainfall
in the mountains will be light, only about .10 to .20 inch,
and no snow is expected below 8000 feet. All precipitation
should end by late Sunday morning. Clouds will increase
Sunday night into Monday ahead of a stronger system.

Showers will return Monday afternoon and evening over the
higher terrain, kicking off a prolonged wet period for the
mountains. Furthermore, breezy winds are expected across the
higher terrain of southeast Oregon Monday afternoon. Snow
levels will remain quite high Monday, between 7000 and 9000
feet, so any snowfall will be limited to the highest peaks.
Rainfall amounts of one quarter to one half of an inch are
expected Monday across the northern mountains as moisture
deepens across the region.

LONG TERM...Tuesday through Saturday...A cloudy and wet long
term period is on deck. Rounds of moisture will stream into
the region over the week, as an upper-level trough meanders
in the Gulf of Alaska. Embedded shortwaves troughs in the
flow will provide enhanced periods of lift as the area
stays under southwesterly-westerly flow aloft. In between
these shortwaves troughs, brief weak upper-level shortwave
ridging will exist. To begin Tuesday, moisture will be riding
over a weak shortwave ridge, keeping PoPs 10-40% in lower
elevations and 40-70% in higher elevations. Snow levels at
that time will be near 8000 ft MSL. Wednesday will begin the
first bigger push of moisture, with a preceding warm front
in the morning followed by a cold front in the afternoon/
evening. Highest PoPs for lower elevations will be 40-60%,
while higher elevations are 50-90%. Despite it being a "cold"
front, the air mass following will keep high temperatures
5-10 degrees above normal. Snow levels will drop to 6500-8000
feet going west-to-east in the CWA, with gusty winds also
being a concern during this time, particularly in SE OR. While
a low chance (15-20%), it is mentionable that both the ECMWF
and GFS are forecasting a small amount of instability 00z/Thu
to 12z/Thu along the Boise foothills north to McCall. Was given
confidence from both long range models forecasting this slight
instability signal to keep chance of thunderstorms in forecast
grids. Variation in model solution increases Thursday and
beyond with shortwave timing and intensity. Regardless, another
round of moisture with another shortwave trough will move in
sometime Thursday, bringing widespread precipitation and
temperatures near normal for this time of year. Moving into
the weekend time frame, models agree on another round of cooler
air and moisture sometime Friday, before models paint greater
variation between solutions. The main point of contention
appears to be the intensity of an upper-level ridge building
across the Western U.S., which will determine what comes after.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....JM
SHORT TERM...JDS
LONG TERM....CH