301
FXUS65 KPIH 222334
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
434 PM MST Sat Nov 22 2025

.KEY MESSAGES...

- More patchy dense fog expected tonight into Sunday morning.

- Remaining dry through the weekend before Monday cold front.

- Continued unsettled pattern and turning colder through the
  Thanksgiving weekend.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 136 PM MST Sat Nov 22 2025

This morning`s patchy dense fog and low stratus continues to slowly
erode from the south and you can find some sunshine at times. Those
of us who make it out from underneath the stratus blanket will warm
into the upper 40s to even near 50 degrees, and the rest will remain
in the low to mid 40s. Look for more of the same tonight as some
patchy dense fog and low stratus keep hanging around until we can
get Monday`s cold front to blow it out of here. Any patchy dense fog
tonight doesn`t look too widespread, so not anticipating another
Dense Fog Advisory at this time. Models are showing a thin band of
fog from Burley along the interstate up towards Pocatello and
Blackfoot where we are seeing some of the most clearing, along with
some fog out across the Arco desert. The HREF gives it about a 30 to
40 percent chance of visibility dropping below a half mile at times
tonight within that band of fog, but that seems heavily weighted by
the HRRR while the NAM shows visibility closer to 1 to 2 miles and
the NBM only gives a 10 percent chance of visibility blow a mile.
There`s about a 20 percent chance for fog to work its way into Idaho
Falls, too. So still expect to drive into some patches of dense fog
early Sunday morning if you are out and about and be alert and
cautious. Sunday afternoon will be nearly a repeat of today. Late
Sunday night our next cold front will begin to move into the area.
More on that below...

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 136 PM MST Sat Nov 22 2025

Fast moving shortwave drives across Idaho with cold front passage
during the day Monday. Impacts are still expected to remain minor
with light precipitation and snow accumulation focused mainly over
the higher terrain. Winds increase along and behind the front, with
speeds still expected to reach 25-30 mph and gusts around/over 40
mph especially across the Upper Snake Plain. There is still
uncertainty headed into the Thanksgiving holiday travel period, as
the ensemble clusters show signs of the next intermountain ridge
breaking down by Thanksgiving. By Friday, half of the clusters
depict a trough shifting into the western states while the other
half maintain a ridge over the coastal states or intermountain west.
 Either way, they all show some sort of a trough across or already
through the western states by the weekend, with nearly half of the
clusters depicting a deep trough similar to the operational GFS. It
is also fair to note that the slower or less amplified clusters
appear to favor the EC ensembles. The pattern stays somewhat
unsettled and trending colder into the weekend and early next week.
There is  potential for a much colder airmass early next week on the
periphery of the polar chill that may be headed for the north-
central states.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 434 PM MST Sat Nov 22 2025

As expected, stratus has slowly retreated north of KIDA and
dissipated at KSUN, and all TAF terminals have returned to VFR.
Plenty of moisture remains available overnight tonight with
initially clear skies and good cooling, but the overall airmass may
be just a touch drier than last night, and the NBM, HRRR, and MOS
guidance is all leaning toward less fog and low stratus tonight with
impacts being more localized. Suspect we will need to do some "now-
casting" later based on satellite and webcam trends, but for now it
seems reasonable to maintain 5SM BR FEW004 at the Snake Plain
corridor terminals (and have added VCFG at KIDA based on recent HRRR
runs). Have pushed the timing a bit later than the previous
forecast. Mostly clear skies are expected late morning and afternoon
Sunday, before high-level clouds start to move in from the west in
the evening ahead of our next approaching shortwave trough that will
cross the region Monday.

&&

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

&&

$$

SHORT TERM...AMM
LONG TERM...DMH
AVIATION...01