407
FXUS65 KPIH 180817
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
117 AM MST Thu Dec 18 2025

.KEY MESSAGES...

- Moderate to heavy mountain snow Today and Friday. Breezy to
  windy conditions Friday.

- Weather pattern to remain active into the week of Christmas

- Continued above normal temperatures through Christmas.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 1210 AM MST Thu Dec 18 2025

Had a bit of a break after the extreme winds yesterday but the
next storm system will bring snow to the central mountains later
this morning and continue off and on through Friday night. Will
move into the eastern mountains this afternoon. Snow levels
begin at valley floors and even the Snake River Plain may see
snow at the beginning of the event but will quickly change to
rain as warm air returns with snow levels by Friday morning in
the 6 to 7 thousand foot range once again. Friday will also see
a return to very breezy to windy conditions with 20 to 30 mph
sustained winds expected with 30 to 40 mph gusts. Will be
nowhere near yesterdays event wind speed wise. Warmth continues
with highs today much cooler with 30s mountains and upper 30s to
lower 40s valleys. Lows tonight in the 20s mountains to mid to
upper 30s valleys. Highs Friday mid 40s to lower 50s valleys
with all rain and 30s to lower 40s mountains. It will be much
cooler Friday night with lows single digits to teens mountains
and 20s valleys. With the winter storm warnings and advisories
expecting over 10 inches of snow above 6 thousand feet in the
warning areas and above 6 inches in the advisory areas. Mountain
passes like Galena Summit will likely be well over a foot of
snow.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 210 PM MST Wed Dec 17 2025

Precipitation tails off during the day Saturday along with the
wind.

We are seeing amplification of the Pacific trough along or off
the coast beginning Sunday, resulting in increasing southwest
flow into Idaho. Ensembles and clusters are in relative
agreement in continuing precipitation chances through some of
the heaviest travel days of the season. Given the southwest flow
aloft, temperatures remain in the very mild pattern, and snow
levels remain high. Thus lower elevations are expected to see
all rain, with snow levels around/above 6000 ft. It`s not great
news for anyone at lower elevations hoping for a White
Christmas, but the mountains will stand to see additions to the
snow pack. Those traveling for the holidays will want to keep an
eye on upcoming forecasts, as fluctuating snow levels could
provide potential impacts for travel routes over higher
elevation passes.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1030 PM MST Wed Dec 17 2025

Winds have backed off for all sites except BYI where there are
still gusts of 15 to 20 kts. Winds will continue to drop off.
Expect mostly clear skies with mostly upper-level clouds
overnight. Northwest flow aloft sets up over the area overnight
and continues into tomorrow, Thursday. Models continue to show a
wave of moisture moving into the area by late tomorrow
morning/early afternoon through the northwest flow aloft. Expect
snow showers at SUN and DIJ and a rain/snow mix for PIH and IDA
and rain for BYI. Temperatures look to warm up tomorrow
afternoon into the early evening. SUN and DIJ should remain snow
with IFR conditions. Precipitation at IDA and PIH will likely
turn to rain with mostly just MVFR conditions. Though with the
onset of precipitation, IFR conditions could occur at IDA and
PIH before conditions improve as snow turns to a rain/snow mix
and then just rain later in the day. Winds will get slightly
gusty tomorrow with gusts of 20 to 25 kts likely for PIH, IDA,
BYI and DIJ. Winds at the surface will be from the south.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 AM this morning to 5 AM MST
Saturday for IDZ060-063-064-066.
Winter Storm Warning from 5 AM early this morning to 5 AM MST
Saturday for IDZ071>074.

&&

$$

UPDATE...AMM
SHORT TERM...GK
LONG TERM...DMH
AVIATION...TW