699
FXUS65 KPIH 060544
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1044 PM MST Fri Dec 5 2025

.KEY MESSAGES...

- Significant snowfall potential still exists especially across
  the southern and eastern highlands. Winter Storm Warnings and
  Winter Storm Advisories remain in effect through tonight.

- Windy conditions are expected this evening and overnight.

- Unsettled mild conditions in place for much of the upcoming
  week.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 153 PM MST Fri Dec 5 2025

Complex northwest flow scenario continues to evolve over East
Idaho into this weekend. Satellite imagery shows next
significant shortwave in the pattern already crossing
Seattle/Vancouver region of the PacNW this afternoon, with
strong moisture field to the south. Regional radar mosaic shows
precipitation already falling across much of NE Oregon this
afternoon, ready to spill into Idaho. Nose of warm surface air
has pushed into the Magic Valley/Raft River regions and
partially nosed up into the Lower Snake Plain with temperatures
and surface dew points above freezing. Precipitation builds back
into the region this afternoon, and some of this should fall as
rain at lower elevations, especially across the aforementioned
areas. Liquid QPF still looks to be highest across the southeast
highlands, generally from the Big Hole Range south to the Bear
River Range, and west to the Albion Mtns and South Hills.
Temperatures have warmed sufficiently to push snow levels to
between 6500 and 7000 ft across the south, but northeast push of
the warmest air should be limited to this evening before snow
levels begin to fall again. Main batch of precipitation drives
through this evening, decreasing to mainly orographic showers
for the remainder of the night, and then gradually dissipating
early Saturday. The probabilistic range of precipitation amounts
south and east of the Snake Plain interstate corridor range
0.20-0.60" at lower elevations and 0.5-1.5" at higher elevations
through tonight. NBM means fall generally between 0.30" and
1.0", which offer much more reasonable expectations for snowfall
by tomorrow morning. The warm air intrusion will limit or
eliminate accumulations at lower elevations, but higher
elevations could still see significant accumulations through the
overnight. Thus will maintain most of the current Winter
headlines, but will cancel the Winter Weather Advisory for the
Upper Snake River Plain zone as additional accumulations look to
be minor at best. Winds remain the other concern for the
overnight as surface gradient tightens in combination with
increasing mid level winds. Although there is the expectation
that some locations will reach 30 mph sustained for the evening
and overnight, but the coverage does not look widespread enough
to not light up entire zones with a Wind Advisory.

For Saturday into Saturday night, light snowfall continues over
a few higher terrain zones, notably portions of the central
mountains and along the Wyoming border. Accumulations looks
significantly lighter with areas above 7000 ft topping out at an
additional 2-4". Daytime highs remain mild at lower elevations,
and winds are expected to decrease from tonight`s peaks.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 153 PM MST Fri Dec 5 2025

Confidence is high in above normal temperatures for much of the
extended period of the forecast. The greater forecast challenge lies
with respect to placement and timing of precipitation as the overall
pattern looks to remain messy with clouds and precipitation in place
despite the warmer than normal temperatures. Valley temperatures on
Sunday will be in the upper 30s to mid 40s but by Monday, should
climb into the mid to upper 40s. This upward trend continues into
Tuesday and towards the latter part of next week with upper 40s to
lower 50s appearing very likely despite all the cloud cover in
place. Could even get some mid 50s into parts of the lower Snake
Plain and Magic Valley. Mountain locations will also see above
normal temperatures but the warmup wont be as significant keeping
temps in the upper 30s to lower 40s for most days. The precipitation
portion of the forecast remains messy with wide variability on
potential outcomes but it seems though models have come into
slightly better agreement over the last 24 hours. The stream of
Pacific moisture looks to shift north by the middle part of next
week which should keep PoPs limited to the higher terrain of the
central mountains and up towards the Island Park area with lower
chances as you move down the eastern highlands towards the Bear Lake
area. Valley locations now look like they`ll miss a majority of
precip based off latest model runs but it`s still hard to have too
much confidence based on how much they`ve been varying over the past
few cycles. We`ll see. Could have a few breezy days as well over the
area with a tight pressure gradient in place but still some model
variability with just how strong they will be as well. Right now,
we`ll call it a breezy period. The one sure thing is that temps will
be on the warmer side of normal for early to mid December by 10 to
15 degrees for most locations.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1044 PM MST Fri Dec 5 2025

Steady precipitation is trying to taper off an hour or two early
this evening at a few terminals, and we`ve cautiously been able to
back off slightly on some cig/vsby impacts via amendments and the
06z TAFs as trends allow. Otherwise, forecast remains on track,
and LLWS concerns continue for the next 3-5 hours before the
strongest surface winds materialize and coincide with a slight
relaxing of the flow aloft. Previous discussion is below.

Issued at 449 PM MST Fri Dec 5 2025

Southeast Idaho is incredibly moist with another round of
organized/widespread rain and snow now moving in. The result will be
a period of IFR conditions for cigs/vsbys/BR (LIFR at KIDA which is
currently sitting below airfield minimums) into the overnight with
increasing WSW winds during and behind the precip. Precip should
shut down by 08-11z/1-4am, with low stratus a bit slower to
clear/lift with updated timing outlined in the latest TAFs. Winds
are rapidly increasing aloft first as we speak, so we have also
added periods of LLWS this evening into tonight before the flow
aloft starts to relax combined with better mixing to the surface.
West winds at 2,000 feet AGL may reach 50kts at KPIH and KBYI. If
you`re looking for VFR conditions, look toward sunrise for KSUN and
KBYI, and Saturday afternoon for everyone else, although it will
remain breezy throughout the day. Confidence is lowest on exactly
when clouds will try to retreat from KIDA and KDIJ.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 5 AM MST Saturday for IDZ058>066.
Winter Weather Advisory until 5 AM MST Saturday for IDZ072-073.

&&

$$

SHORT TERM...DMH
LONG TERM...McKaughan
AVIATION...01