Flood in Idaho, December 24 to 25, 2025

Area Forecast Discussion
National Weather Service Pocatello ID
436 PM MST Wed Dec 24 2025

.KEY MESSAGES...

- Warm winter storm brings rain to most, snow above 7000ft
  elevation. Heaviest precipitation amounts this evening. Winter
  headlines continue until 5 PM Christmas Day.

- Very windy in the Albion Mountains. Wind Advisory continues
  until 5 PM tonight.

- Near record temperatures continue until Friday, then cool to
  normal by Saturday.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 1234 PM MST Wed Dec 24 2025

Massive upper level low off the northern CA coast continues to
pump a mild and moist air mass over the Sierra Nevada into the
Great Basin and northern Rockies. This low will eventually move
inland and cross through the region on Sat/Sat night. Until
then, expect rain to high elevations with the heaviest expected
this evening, with rates in the upper Snake River highlands
reaching 0.10 of an inch per hour or more. This intense low
also has some wind aloft with it, which enhances the
precipitation production. The Winter Storm Warnings and Winter
Weather Advisories will continue as-is, with less precipitation
for Christmas night/Fri. However, that 24 hour period may need
some winter highlights as temperatures cool some 5 to 10 deg F
from Christmas Day to Fri. This will mean more snow production
to lower elevations.

Temperatures have already reached records for the date today,
and despite clouds and rain more records will likely fall on
Christmas Day. The cool down starts Fri as mentioned, then
another 10 to 15 deg F from Fri to Sat. By then, skies will at
least partially clear and cold air behind this storm with some
west to northwest wind at least briefly should bring in the
colder air.

The very windy conditions over the south central highlands
should diminish this afternoon; wind at KPIH and KBYI airports
show even these locations are still right around Wind Advisory
thresholds, with expectations of subsiding by early evening. As
the low moves across, wind will stay in the 15 to 30 mph range
with higher gusts Christmas Day through Sat, which is just below
Advisory thresholds. Wind will shift to west by Fri night, and
northwest on Sat.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Issued at 1234
PM MST Wed Dec 24 2025

The storm that brought all the precipitation will have moved out
by late Sat night, allowing an upper level ridge to move into
the US west coast. This will clear skies, but the northerly wind
behind the storm will keep cold air from southern Canada moving
into the region. This will moderate the warming, keeping
temperatures below 40 deg F for most until Wed afternoon, when
that kind of warmth returns to the Snake River plain. Overnight
lows should be around climatic normals, with teens in the Snake
River plain, single digits and some below zero readings in the
central Idaho mountains. Wind by Sun afternoon as the high
pressure strengthens should return to light. This may cause
night and morning fog issues, but will have to see how much
moisture is available in snow pack or standing water.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 435 PM MST Wed Dec 24 2025

Southerly, downslope winds that are locally stronger near KPIH have
resulted in very breezy and dry conditions for the terminal. Have
more heavily relied on the HRRR for the WX portion of the forecast
as the latest run more accurately reflects the current conditions as
compared to other HREF members. Have forecast MVFR CIGs and/or VIS
for all terminals with the exception of KBYI, as well as a period of
IFR VIS at KDIJ overnight tonight. Winds will remain breezy into the
first part of Thursday.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 5 PM MST this afternoon for IDZ056-057.
Winter Weather Advisory until 5 PM MST Thursday for IDZ069-071-
072.
Winter Storm Warning until 5 PM MST Thursday for IDZ073-074.

&&

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