679
FXUS65 KPIH 061135
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
435 AM MST Sat Dec 6 2025

.KEY MESSAGES...

- Winter storm wraps up this morning, Winter Storm Watches and
  Advisories extended another 6 hours.

- Light rain and snow picks up again Sunday afternoon for many
  locations. Precipitation threat continues each period through
  at least Thursday.

- Windy to very windy conditions should peak today in the Snake
  River plain/eastern Magic Valley/southern hills and subside by
  evening.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 159 AM MST Sat Dec 6 2025

Still quite a bit of reflectivity showing up on radars to the
west, so have extended the Warnings and Advisories for another 6
hours, when the QPF forecast diminishes to 0.01 or less for
nearly all areas. Light accumulations continue overnight and
then Sunday afternoon the accumulations start to increase, but
most accumulations are below 0.08 of an inch for each 6 hour
period, save for a few in the central Idaho mountains. That
light accretion should not warrant highlights for the rest of
this near-term period with limited areas on Sun/Sun night and
just a few more areas on Mon/Mon night.

The reason for the light accumulations is partially caused by
the continued mild temperatures for the time of year. Widespread
40s for highs in the Snake River plain and even middle to upper
30s for a location like Stanley indicate just how warm it is
expected to be. The cloud cover, except for tonight, will keep
overnight lows mild the subsequent nights in this period.

Another forecast element of concern is the windy to very windy
conditions in the Snake River plain, the eastern Magic Valley,
and the southern highlands. Since there is little vertical
mixing, the very strong wind aloft appears to be staying there,
away from the surface. The strongest winds are expected prior to
noon today, with a gradual dropoff overnight. By Sun morning,
it should return to 17KT/20mph or less sustained.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 159 AM MST Sat Dec 6 2025

Cluster analysis indicates that about 65 to 75 percent of the
members indicate a continued warm 500mb anomaly with the storm
track staying right where it is, which puts eastern Idaho on the
warm side but very close to the storm track. The remainder of
the solutions pump up the upper level ridge on the coast to push
the storm track farther north and away from eastern Idaho, or
maybe just brush the northern edge of the forecast area. In
short, there is no high energy trough to break this down and
return cold temperatures and bring a massive snow storm in the
classic style. So this upper level northwest flow continues for
at least another week. Another surge of moisture occurs on Tue
night/Wed/Wed night. However, the temperatures appear to peak
with this feature, with Pocatello airport forecast to be in the
mid-50s! Not a record, but close. Even Stanley may warm to the
low 40s for a peak on Tue. Not good news for snow-makers, but
the precipitation will make up for an incredibly dry autumn.

One concern will be the wind. The GFS guidance has been
consistently forecasting a Wind Advisory/High Wind Warning event
with this mid-week storm mentioned above. The ECMWF is also very
strong and would verify a Wind Advisory.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 425 AM MST Sat Dec 6 2025

Storm that has been around the previous two days will wrap up
this morning, with scattered SHRA and some marginal VFR CIGs to
deal with. Valley airdromes of KBYI, KPIH, and KIDA will
struggle with these CIGs through the morning, then break out
with occasional CIGs in KPIH and KIDA for the afternoon, but
above 4000ft AGL. Low Level Windshear will also be strong for
KBYI and KPIH but the upper level wind will subside by mid-
morning so that it is no longer a factor. Wind conditions at the
surface will continue until mid-afternoon, then subside sometime
around 07/00Z. KSUN will have the least amount of trouble, still
in the precipitation shadow, with no CIG expected and just light
wind in its sheltered valley. The airdrome with the most
problems appears to be KDIJ. Indications are that it should stay
marginal VFR for CIG until 07/00Z, then return to marginal VFR
about 6 hours later. SHRA also seems to linger there all day,
more intense in the morning than in the afternoon.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 11 AM MST this morning for
IDZ058>066.
Winter Weather Advisory until 11 AM MST this morning for
IDZ072-073.

&&

$$

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