416
FXUS65 KPIH 291953
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
153 PM MDT Thu Oct 29 2026

.KEY MESSAGES...

- Slightly warmer highs today and Friday.

- Showers return to the Central Mountains as early as Friday.

- More organized and widespread precipitation returns for the
  weekend as temperatures begin to drop.

&&

.DISCUSSION...
Issued at 1209 PM MDT Thu Oct 29 2026

There is currently dry, southwesterly flow aloft over southern
Idaho. Also, currently there is an upper level low centered just
off the coast of Washington as part of an overall trough that
extends much farther south to off the coast of California,
where there is ample moisture available. This low/trough will
drive the weather/precipitation over the upcoming weekend.

We are in-between systems today. Expect dry conditions today
with temperatures warming a few degrees, compared to yesterday,
with southwesterly flow aloft. Highs today reach the mid to
upper 50s for most of us in the lower elevations with more
cities reaching the upper 50s. Winds will be fairly light today
with gusts around 15 to 20 mph.

Friday morning look for patchy fog, especially in lower
elevations near water sources. Expect better fog chances
Saturday and, especially, Sunday and Monday mornings. Friday
look for slightly warmer temperatures, compared to Thursday,
with highs in the 50s to near 60s. On Friday, the low currently
off the Washington coast and the associated trough will gather
Pacific moisture and eject a weak shortwave through Idaho. Wind
gusts begin to increase on Friday, closer to 20-30 mph for many.
This will also bring some isolated to scattered showers back to
the Central Mountains as early as Friday morning with coverage
increasing a bit on Friday afternoon through early Saturday.
This first "quick" round of precipitation will bring about 0.10
to 0.20 inches of precipitation the the area which will also
mean to expect a few inches of snow up on top of the mountains,
too. Most of this will be above pass level, but there is about a
half inch to an inch of snow in the current forecast for Galena
Summit from Friday morning to Saturday morning.

Saturday late afternoon into the early evening models still
show a chance for 0.01 to 0.08 inch of rain across lower
elevations that will likely have some impacts on Halloween
activities. However, the bulk of the precipitation is still
arriving later Saturday evening through Sunday and lingering
into Monday morning.

By late Saturday into Sunday the low off the Washington coast
begins to move and makes it way inland aided by an deepening
trough, which will really pick up more Pacific moisture and
transport it over southeastern Idaho. This more organized round
of precipitation will begin in the Central Mountains/Wood River
Valley/eastern Magic Valley as early as 6 PM Saturday and then
spread eastward throughout the night. The NBM model is still
showing about an 80 to 100 percent chance of the entire CWA
receiving at least 0.25 inch of precipitation from 5 AM Saturday
to 5 AM Monday. Precipitation amounts have not changed much
from yesterdays model run. It still seems likely that many will
see 0.25 to 0.50 inches in the eastern Magic Valley, 0.50 to
0.75 inches in the Snake River Plain and lower elevations of the
Eastern Highlands and Central Mountains. For higher elevations
(above 8000 to 85000 feet) precipitation will be pushing 0.80
to 1.50 inches, especially for Sun Valley Region, Big Lost
Highlands/Copper Basin, Lost River Range, and the Montana Divide
as well as the Southern areas along the Utah border including
the Wasatch mountains. Temperatures will still be "warm" on
Saturday with highs in the 50s, but by Sunday our highs will
drop into the mid and upper 40s. Snow impacts seem likely at
Galena Summit Saturday night into Sunday morning with the
forecast still showing 4-6" of snow there. A winter weather
advisory for the Sun Valley Region and the Big Lost Highlands
above 7500 to 8000 feet for Saturday evening through Sunday
will likely be needed. Elsewhere, the bulk of our snow is
expected to remain above most of the rest of our mountain
passes, but that could change easily with temperature changes of
just a few degrees. Even though snow levels will start high,
convection can lower snow levels, which could drop snow levels
to pass levels especially for areas like Emigration and Raynolds
pass.

A few showers linger on Monday morning, but we will be drying out
from west to east by that point and high pressure builds in over the
area through mid week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1010 AM MDT Thu Oct 29 2026

VFR conditions continue with high-level cloud cover gradually
thickening and streaming northeastward across eastern Idaho.
Winds will remain generally light and terrain-driven. Moisture
increases overnight ahead of an approaching shortwave trough,
lowering clouds toward SCT060-SCT090 ft AGL. High-resolution
guidance supports VCSH developing at KSUN and KBYI around
09Z10Z Friday. Precipitation chances expand eastward into the
Snake River Plain late Friday morning, introducing VCSH at KPIH
after 15Z. KIDA and KDIJ are expected to remain dry through 18Z
Friday.

&&

.FIRE WEATHER...
Issued at 233 AM MDT Thu Oct 29 2026

We stay mild and dry today as we are in between systems. Highs will
range from mid to upper 50s in most of the lower elevations with
wind gusts around 15-20 mph and min RHs around 30 to 50 percent. A
shortwave passing through on Friday will bring precipitation chances
back to the Central Mountains first and then expand eastward
overnight into Saturday. However, it`s Saturday evening through
Sunday night that the bulk of the next precipitation will impact the
entire area. This will bring plenty of low elevation rainfall and
mountain snowfall. It seems likely that many will see 0.25 to 0.50
inches in the eastern Magic Valley, 0.50 to 0.75 inches in the Snake
River Plain and lower elevations of the Eastern Highlands and
Central Mountains, while the higher elevations will be pushing 0.80
to 1.50 inches. Temperatures will also drop during the weekend with
highs mainly in the 40s for Sunday and Monday.

&&

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

&&

$$

DISCUSSION...TW
AVIATION...DMH
FIRE WEATHER...AMM