264
FXUS65 KPIH 011124
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
424 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 accumation 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 /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 414 AM MST Mon Dec 1 2025

Widespread stratus and fog this morning wreaking havoc with
airdromes. KBYI seems to be the least affected thanks to a
mainly southerly wind keeping the stratus and fog north of the
airport. KPIH slightly affected with marginal VFR CIGs this
moring, with a risk of IFR during the first three hours after
sunrise, until around 01/17Z. By early afternoon KPIH should be
VFR and stay that way overnight. Development of precipitation
down at the Snake River plain airports appears to be hard to
get, so not looking for extreme impact this evening. KIDA is in
the heart of the stratus deck. Do not expect a break out until
01/23Z at the earliest. There is also a shortly after sunrise
threat of IFR conditions for VSBY but mainly CIG until 01/17Z.
However, it is mainly marginal VFR CIGs the rest of the day. CIG
will start coming down again late tonight. The light and
variable wind at KSUN has brought CIG and VSBY way down. With
any luck the airdrome will see marginal VFR around 01/16Z, or
once wind increases--whichever comes first. An incoming trough
will bring back snow and low elevation rain and snow which peaks
on Tuesday during the day, for more problems and impacts to
aviation interests.


&&

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

&&

$$

SHORT TERM...Messick
LONG TERM...Messick
AVIATION...Messick