893
FXUS65 KPIH 160836
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
136 AM MST Sun Nov 16 2025

.KEY MESSAGES...

- Showery weather with low confidence of timing and amount for
  any location today through Tuesday night.

- Cooler temperatures, but still above climatic normals for the
  time of year through the period.

- Threat of precipitation is less, generally, starting Tuesday,
  and continuing low for the rest of the week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 111 AM MST Sun Nov 16 2025

Weak warm front entered the southern half of the forecast area,
but has produced very little in terms of clouds and
precipitation, but has kept temperatures mild over that region,
which extends from east of Pocatello over into the Magic Valley.
So temperatures in the northern half are just slightly higher at
this time. The approach of the front from the south means that
to the north there is some northerly wind, which is still gusty
in the major NW-SE oriented valleys there, such as the Wood
River Valley. Otherwise, the nature of the warm front with
warming aloft means more stable conditions and outside of these
valleys winds are light and variable.

A look across deterministic guidance and the averaged NBM/WPC
guidance shows that the precipitation amounts and timing,
especially through the first 48 hours of the forecast, through
Mon night, should be taken with a huge rain of salt. Some
periods in the southern range has rather large amounts of
precipitation, but only in some of the guidance. The only real
consistency is that starting Tue the overall amounts and the
variation decrease, but that timing is still a low confidence
situation.

Cloud cover will keep temperatures mild, and the warm air mass
moving in behind this warm front will keep temperatures well
above climatic normals; just not at the records of the recent
days. This is true through this period and into the extended.

Wind is light through this period, with weak association with
the slope-valley effect. This makes sense with the cloud cover.
Only today as any wind approaching gusty, mainly due to the
closeness of the warm front.


&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Issued at 111 AM MST Sun Nov 16 2025

Cluster products were not available for analysis. However,
overnight guidance shows a wind diversity of solutions. For
example the deterministic guidance from the American GFS
indicates just below mentionable precipitation risk at 13
percent for Thu at the Pocatello Airport, while the ECMWF
guidance has likely probabilities on the very same period. This
spread is likely due to lack of specific equations for the
autumn period with some guidance, where equations are based on
"summer" and "winter." So the forecast for precipitation for
this period is subject to major changes as time progresses.

There is some agreement that near to above normal temperatures
are likely both for highs and lows, with no forecast below
normal.

There may be another feature arriving next weekend that will
kick up the wind for Sat, 22 November.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1033 PM MST Sat Nov 15 2025

Only a few minor tweaks were required with the fresh 06z TAF
package...either because changes weren`t needed, or confidence is
too low for big nudges yet given some lack of agreement in our
various models. Multiple large shields of clouds in the mid- and
upper-levels will continue to build northward across southeast Idaho
this evening and tonight, as a warm front also lifts north (now
approaching KBYI and KPIH from the south). As expected, a few
showers are likely reaching the ground along the front, but with not
quite enough coverage to include VCSH beyond KBYI (where so far
echoes on radar have manifested as increased/lowering clouds only),
with a continued better chance of increasing showers kicking off
later. Thus, have generally held off until 07z/12am at KSUN, and 10-
12z/3-5 am at KPIH/KIDA/KDIJ, for initiating VCSH (just slight
tweaks to previously forecast timing there), followed by an
increasing trend in shower coverage thereafter during the day Sunday
with -SHRA for all terminals. Agreement is unfortunately not great
among the 00z HREF suite on timing and placement of the most
persistent showers, but we don`t yet have enough confidence to back
off from -SHRA for any organized period at any of the TAF terminals.
Cigs are generally expected to remain VFR through late afternoon
Sunday with the showers. Dry air at the sfc will take some time to
overcome, and southerly downslope winds are expected especially at
KPIH, so it`s possible VCSH and -SHRA groups may begin an hour or
two too early at KBYI and KPIH in the current forecast. Have also
maintained winds slightly above guidance after 19z/noon at KPIH due
to that southerly downslope expectation with gusts to 20kts
possible. As low pressure approaches our area Sunday evening from
the southwest, many guidance sources are advertising a more
significant drop in cigs to MVFR along with a continued trend into
more widespread showers or rain after sunset, affecting especially
KPIH, KIDA, and KDIJ. Interestingly, while the signal remains
ominous in the HRRR and eventually MOS guidance, the NBM has backed
off...or at least trended later...on increasing impacts especially
with cigs. Will continue to monitor trends.

&&

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

&&

$$

SHORT TERM...Messick
LONG TERM...Messick
AVIATION...01