346
FXUS65 KPIH 230958
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
258 AM MST Sun Feb 23 2025

.SHORT TERM...Today through Monday Night.
Radar and satellite imagery this morning show precipitation moving
into western Idaho and cloud cover on the increase in eastern Idaho
as our next system is arriving. As precipitation spreads over the
area today, look for it to begin as snow and then switch over to
rain as snow levels steadily climb throughout the day to around 7000-
8000 feet by this evening. Total precipitation has remained
relatively consistent with the past few forecast updates, but we
have seen an increase in QPF in the Big Hole Mountains, so have gone
ahead and issued a Winter Weather Advisory for this area. This is in
addition to the Winter Weather Advisory already out for the Sawtooth
area and both advisories go until 11 AM MST Monday. Briefly
considered adding the Island Park area into the advisories, but
given that snow totals for that zone generally range from 2 to 5
inches (aside from higher totals up in the mountains), decided
against it. Within the advisory area around the Sawtooths, the
highest snow totals will be above 7000 feet and generally range from
5 to 10 inches with travel impacts expected along parts of Hwy 75,
particularly over Galena Summit, and locally higher amounts above
pass level and. For the advisory in the Big Holes, snow totals will
range from 3 to 8 inches below 7000 feet and 8 to 12 inches above
7000 feet with travel impacts expected through Pine Creek Pass. The
latest HREF data gives these two summits/passes a 50 to 70 percent
chance of seeing at least 8 inches of snow by Monday afternoon, and
it is within these areas that QPF totals will range from 1 to 2
inches.

For areas outside of the advisories, total QPF will be up to about a
quarter inch in the valleys and 0.25 to 0.50 inches in the mid
elevations as highs today in the upper 30s to low 40s will mean more
rain than snow, or at least a soggy rain/snow mix. Snow totals will
most likely be up to about an inch in the Snake River Plain and 1 to
3 inches throughout the Eastern Highlands. Winds will increase
throughout today with southwest gusts of 30 to 35 mph for many and
higher gusts of 40 to 45 mph on ridge tops. As our warming trend
continues, overnight temperatures in parts of the eastern Magic
Valley, Snake River Plain, and South Hills will remain at or just
above freezing with even warmer highs on Monday afternoon pushing
into the 40s and 50s to aid in the melting of snow in the lower
elevations. For more information on potential impacts due to this
melting, refer to the hydrology discussion below.
AMM

.LONG TERM...Tuesday through Sunday.
The last round of moisture with our multi-day event winds down
Tuesday night. Light rain and/or snow amounts for this period are
expected. It will be pretty breezy along with cooler afternoon
temperatures. The rest of the week remains on the warm side, with
the caveat being overnight temperatures will be much colder.
Snowmelt and runoff should continue, BUT those cold lows will slow
down that process somewhat. A Rex Block will keep us dry until
the pattern breaks down next weekend. We may see an uptick next
weekend in terms of snowmelt, etc. Keyes


&&

.AVIATION...12Z Sunday through 12z Monday.
Rain and snow will increase later this morning and continue into
this evening, with some tapering off overnight except for DIJ and
MAYBE SUN...which should hold on to some precipitation into
Monday. We are looking for MVFR/IFR weather during the main period
of precipitation, with those conditions potentially happening
later on if and when a shower impacts a TAF site. Keyes


&&

.HYDROLOGY...
Warm temperatures and incoming precipitation today and very early
next week will induce the potential for minor flooding across some
lower elevations in East Idaho. Most likely areas to be impacted
would be low elevations in the South Hills, Eastern Magic Valley
and Lower Snake River Plain where snow exists below 6000 ft
elevation. Hazards could include elevated flows in small stream
channels and drainages, and ponding in flat areas and upstream of
plugged culverts or road berms. As a result, a Hydrological
Outlook has been issued for the eastern Magic Valley and lower
Snake River Plain south to the Idaho/Utah border where warming
temperatures and melting snow may lead to minor flooding impacts.
Localized lowland flooding may also occur outside of this area but
this product was focused on where temperatures will be warmest.
We will continue to evaluate over the coming days regarding any
changes to this product. Dallon/DMH


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 AM this morning to 11 AM MST
Monday for IDZ064.

Winter Weather Advisory until 11 AM MST Monday for IDZ072-073.

&&

$$