840
FXUS65 KPIH 051142
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
442 AM MST Fri Dec 5 2025

.KEY MESSAGES...

- Winter Storm Warnings and Advisories continue today and
  tonight.

- Windy to very windy conditions develop in the Snake River
  plain and eastern Magic Valley tonight and Saturday.

- Lighter rain and snow accumlations continue Saturday through
  at least Thursday.

- Very windy again Tuesday through Thursday.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 206 AM MST Fri Dec 5 2025

Surface low continues to move through the northwesterly upper
level flow with plenty of moisture to work with. Precipitation
should be its heaviest today and tonight. With the passage of
the surface low to the east, precipitation accumulation rates
drop precipitously. The lowest threat period will be Sat night,
when things take something of a break at that point. Have not
changed anything in the current Winter Storm Warning product.

Temperatures will warm compared to yesterday, but not as quickly
as previous thinking, with temperatures staying below 40 deg F
for much of the area. Warming continues Sat for the highs, then
the clearing skies Sat night produce the coldest overnight lows
for the next six days. The cold start will bring some slight
cooling for Sun, then incoming cloudiness warms the overnight
lows some.

Wind starting late tonight in the eastern Magic Valley and the
lower Snake River plain has some potential to be very windy, and
continue that way through Saturday and into Saturday night. This
is due to the exit of the low to the east and should be a
westerly wind. A Wind Advisory is a distinct possibility but
will let another shift get a look as this time as it is just
short.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Issued at 206 AM MST Fri Dec 5 2025

The upper level ridge at the west coast continues to dominate
this pattern through at least Mon, the point at which cluster
analyses were not available. This ridge has amplified, putting
higher 500mb heights over the forecast area which implies much
warmer temperatures; this is brought out in the MOS guidance
which indicates temperature exceeding 50 deg F by Tue in the
lower elevations, despite clouds and precipitation at 40 percent
chance or greater, depending on elevation. The other remarkable
aspect of this period is strong wind forcast nearly non-stop
until Thu afternoon. The European MOS indicates lower wind
strengths, but still significant. The European suite also has
lower chances for precipitation, and cooler temperatures, which
may be more correct based on current performance of the product
suites.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 428 AM MST Fri Dec 5 2025

A sloppy, ugly day for aviation today, even later this afternoon
for KSUN.

Let`s start there. KSUN should be excellent conditions until
05/21Z when RA/SN starts moving in. Expecting margina VFR
primarily for VSBY in RA/BR. Then around 06/01Z a phase change
to snow reduces VSBY to IFR conditions. This airdrome appears to
be protected from the onslaught of wind other airports will
experience. IFR conditions will last until 06/06Z, then back to
marginal VFR, this time for CIG as the precipitation ceases.

KIDA: Currently having IFR for VSBY and CIG. It could get very
close to field minima during the morning hours after sunrise,
mainly due to FZFG. The conditions improve only slightly mid-
day, then around 06/00Z low IFR conditions return with the
return of SN. Again, during the evening, conditions could
challenge field minima.

KPIH: Expecting BR and some SN to make conditions waver between
marginal VFR and IFR during the early morning, then worsen to
near field minima for the mid to late morning, thanks to FG. By
05/21Z, solid IFR thanks to the return of SN to help improve
VSBY, along with some gusty wind, which should increase to
20G30KT during the evening. IFR due to CIG continues from 05/15Z
onward with only occasional let up.

KDIJ: With SN/BR during the morning, another airport that will
struggle between IFR and marginal VFR. Conditions should
stabilize mid-morning to marginal VFR until around 05/23Z when
SN/BR returns in force, returning IFR conditions due to VSBY.
Onced it returns, it stays through until late in the current
forecast period.

KBYI: Temperatures here will keep the precipitation at RA with
warm advection BR. Another place that will get gusty. In the
late morning there may be brief periods of IFR due to CIG, but
otherwise marginal VFR the entire period with some improvement
late tonight.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 AM MST Saturday for IDZ053-072-
073.
Winter Storm Warning until 5 AM MST Saturday for IDZ058>066.

&&

$$

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