277
FXUS65 KPIH 011740
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1040 AM MST Mon Dec 1 2025

.KEY MESSAGES...

- Light snow moving in tonight and continuing light into Tuesday
  evening. Heaviest in the Island Park/Fremont County region.

- Temperatures staying below 40 degrees for most, 45 for the
  eastern Magic Valley, lower elevations in the southern hills
  and the lower Wood River drainage.

- Next winter storm arrives Friday and continues through Friday
  night, bringing mountain snow, low elevation rain and snow.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 224 AM MST Mon Dec 1 2025

Some light precipitation may come out of the stratus layer that
has spread out everywhere except the Burley /I-84 area, mainly
hovering around 1000 to 2500 ft above the Snake River plain, so
this may mean fog at elevations of 5500ft to 6500ft where the
stratus impinges on the terrain. Have kept the freezing fog that
previous shift put in for today. The wind is finally subsiding
but still many locations exceeding 10 mph, mainly in the Snake
River plain.

Locations in the north will start to receive snow first during
the early evening, spreading southward before midnight.
Accumulations are slightly heavier in the northeast corner than
previous thinking, but average snow accumulation for any
forecast zone is averaging less than 6 inches in the mountains,
and less than 3 inches in the Snake River plain, so see no need
for any formal highlights to the forecast
(Watch/Warning/Advisory).

Temperatures appear to unsteadily rise and fall with the
approach of this trough and the next one on Friday. Afternoon
highs are slightly higher for most locations on Tuesday, then
warmer for everyone from Tuesday to Wednesday. However, still
staying colder than 46 degrees everywhere on Wed, and for most
below 40 degrees, such as the Interstate 15 corridor. Tue night
should be the coldest night of this period, between winter
storms.

Wind will continue to weaken during the day today, but increase
again tonight and peak during the day on Tuesday. Tuesday night
has a northerly component to the wind, which accounts for the
cold temperatures, in the teens for most, on that night. The
air flow shifts back to southwest during Wed afternoon, allowing
temperatures to warm again.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Issued at 224 AM MST Mon Dec 1 2025

The main storm for this period should arrive on Fri or Sat.
Cluster analysis was not available save for a consensus that
Thu should be dry with positive 500mb height anomalies for the
Gem State. Based on deterministic forecasts available, there is
a risk every period except Thu and Thu night. However, the
temperatures are warmer, with freeze-thaw occurring in the Snake
River plain. Wind looks potentially very strong with this Fri-
Sat storm, especially Sat morning. May need Wind Advisory for
this event and Winter Weather Advisory/Winter Storm Warning for
the Sawtooth zone and the eastern mountains south of Driggs to
the Utah border.

&&

.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...Messick
LONG TERM...Messick
AVIATION...GK