786
FXUS65 KPIH 132007
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
107 PM MST Thu Nov 13 2025

.KEY MESSAGES...

- Warm dry ridge breaks down tonight with light showers across
  the region late tonight through Friday night. High snow levels
  limit accumulations to 1-3" primarily at or above pass level.


- Brief break is expected Saturday, then more active pattern
  returns with more widespread precipitation Sunday into Monday.

- Unsettled conditions are possible through midweek, with much
  cooler temperatures arriving for midweek and beyond.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 107 PM MST Thu Nov 13 2025

Satellite imagery shows moisture streaming through the PacNW
early this afternoon ahead of split trough. Upper ridge over
East Idaho shifts east tonight, allowing some of that moisture
to move into our region. Showers begin after midnight tonight
across the central mountains, shifting east across the rest of
East Idaho through the day Friday. Snow levels remain high with
accumulating snow confined to passes or higher, and a mix of
rain/snow down to about 6000 feet Friday night. Liquid
precipitation amounts continue to trend downward, not uncommon
with split flow systems. Have manually adjusted downward some
of the overly aggressive orographic influence on the QPF fields
for Friday and Friday night, bringing some of the forecast snow
totals down across a few mountain ranges. Through Friday night,
accumulations at/above pass level are forecast to be 1-3
inches. The probability of exceeding that at even the highest
elevations is less than 20%.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 107 PM MST Thu Nov 13 2025

Brief break in the pattern occurs on Saturday as East Idaho
lies between departing northern-stream shortwave and southern-
stream low slowly ejecting north. Low shifts northeast through
East Idaho during the day Sunday, quickly followed by amplified
PacNW trough Monday and Tuesday. There are considerable ensemble
cluster differences regarding the strength of this low, and
these differences amplify with passage of the next trough early
in the week. Precipitation returns as early as Saturday night
for southern portions of the forecast, then spreads north
through the day Sunday. Ensemble means and NBM keep snow levels
high until frontal passage late Sunday or Sunday night but the
coldest air doesn`t arrive until Tuesday through Thursday with
daytime highs dropping into the lower 40s or 30s. As such, this
event remains a mountain snow and valley rain or possibly
rain/snow mix by late Monday. Given the variability in model
solutions, it should come as no surprise that there is a
significant spread in precipitation amounts this far out,
either. By the time the shortwave exits Tuesday into Wednesday,
the precipitation will have outrun the coldest air, so the
likelihood of significant snow accumulation at the valley floors
is low.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1052 AM MST Thu Nov 13 2025

Mid and high level moisture is beginning to stream into Idaho
ahead of amplified split trough system moving toward the region.
Skies remain VFR throughout the forecast period, but we begin to
see showers shift into East Idaho overnight through the day
Friday, starting at SUN after 09Z and DIJ after 14Z. Confidence
is lowest for the Snake Plain terminals BYI, PIH, and IDA, but
introduced VCSH after 12Z for each of those sites. Winds
increase slightly overnight, and should be strongest Fri after
18Z behind the cold front.

&&

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

&&

$$

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