763
FXUS65 KPIH 012026
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
126 PM MST Mon Dec 1 2025

.KEY MESSAGES...

- Light snow will spread across East Idaho tonight and continue through
  Tuesday night. Winter driving conditions are expected,
  especially over mountain passes.

- Daytime highs Tuesday in some lower elevations may limit
  snowfall accumulation potential, and snow may mix with rain in
  some areas.

- The next winter storm arrives Friday and continues into the
  weekend, bringing mountain snow and low elevation rain and
  snow.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 126 PM MST Mon Dec 1 2025

Satellite imagery shows broad area of stratus across East Idaho
beginning to be overtopped by moisture moving in ahead of
shortwave crossing the Seattle/Vancouver area this afternoon.
Seeder-feeder light snows may begin late this afternoon and
evening ahead of main precipitation where the low clouds still
persist, but early accumulations due to this should remain very
light. High-res models remain consistent on timing of bringing
light snow into areas along the Montana border including Island
Park this evening, then slowly expanding precipitation across
the remainder of East Idaho tonight into Tuesday. Given the
northwest flow aloft, the bulk of the precipitation through the
event should be focused across the eastern and southern
highlands, with some shadowing expected across northwest
portions of the Snake Plain. Temperatures daytime Tuesday could
be warm enough across the Magic Valley and Raft River regions to
support a brief mix of rain/snow during the afternoon, and will
limit accumulation potential further north in the Snake Plain.
Total accumulations remain similar to previous forecast cycle,
generally up to an inch for most of the Snake Plain (lower in
the Magic Valley), trending toward 2-3" north toward Monida Pass
and Ashton Hill. Highland areas east of I-15 see accumulations
rise to 4-6" with locally higher amounts at and above pass
level. Further west, lesser accumulations are forecast for the
central mountains, especially for areas shadowed in northwest
flow. To the south highlands between I-84/I-86 and the Utah
border, most of the accumulation will be above valley floors,
with most mountain ranges seeing 3-5" for the event. Given these
amounts, winter headlines will NOT be issued, but motorists
could expect winter travel conditions at times through at least
Tuesday night.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 126 PM MST Mon Dec 1 2025

Will start out dry on Wednesday behind the Canadian system as it
pushes east.   It will be cool with highs in the upper 20s to mid
30s.  Going into the latter part of the week the model blends
indicate getting into a moist more zonal flow.  With that expecting
several waves of precipitation late Thursday through Sunday.  There
will be the potential for mountain snowfall accumulation in this
flow pattern.   We are likely to see substantial warming late week
into the weekend and early next week.  By Saturday snow levels will
likely rise to the 6 thousand foot level so will likely see some
rain in lower elevations with the late week and weekend
precipitation.  Grids indicating the heaviest snow in the eastern
mountains near Wyoming border Friday through Sunday.  At least a low
chance some areas above 6 thousand feet could see 6 inches but
extremely high uncertainty with any timing  and precipitation
amounts that far out into forecast period.  Friday through Monday
expect high temperatures in the 40s in low elevations and 30s to
around 40 in the mountains.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1026 AM MST Mon Dec 1 2025

Main impact will be fog and stratus into early afternoon with
LIFR conditions at SUN but expect improvement by 20Z. BYI and
PIH expected to remain VFR this afternoon. Kept the IFR to MVFR
conditions at IDA until 23Z and at DIJ through 21Z. Low
confidence in how quickly the lower ceilings dissipate this
afternoon. A system dropping south from the northwest will
likely bring lower ceilings and snow after 18z Tuesday to most
sites.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...DMH
LONG TERM...GK
AVIATION...GK