Winter Storm and Winter Weather in Idaho, February 13 to 15, 2023

Area Forecast Discussion
National Weather Service Pocatello ID
200 PM MST Mon Feb 13 2023

.SHORT TERM...Today through Tuesday Night.
More active winter weather is returning to the area beginning this
evening and continuing through Tuesday. Our next trough is working
its way through the Pacific Northwest and arrives in Eastern
Idaho this evening. Snow begins at the higher elevations of the
Central Mountains, Southern Hills, and Eastern Highlands first
before making it down to the valley floors this evening/tonight on
the leading edge of the trough. Snow will continue on and off
throughout Tuesday across the entire area before eventually
tapering off Tuesday night. In general, snow totals will be fairly
light in the Central Mountains with up to 3 inches at the lower
elevations and 4-6 inches above 7500 feet. Snow will be light in
the Magic Valley with totals under an inch. The Snake Plain can
expect about 2-4 inches. The Eastern Highlands will also see
about 1-4 inches of snow with higher totals up in the mountains.
The highest totals with this system will be up in the Albion
Mountains, Bear River Range, and Big Hole mountains with totals
generally 8-10 inches with some isolated totals up to 12 inches.
As such, Winter Weather Advisories are out for about half eastern
Idaho in part for snow totals, but also for impacts from gusty
winds as discussed below...

The wind plays a role in this forecast as gusts will be strongest
in the Magic Valley and into the Snake Plain tonight into Tuesday
morning with gusts between 35-55 mph. Isolated gusts over 55 mph
will be possible south of the I-86/84 split along I-84 near
Idahome and Malta due to downsloping winds. We will see a bit of a
break in the wind gusts mid morning Tuesday, but still 25-40
mph. While snow totals are expected to be lighter in the Magic
Valley where the strongest winds will be, hence the Wind Advisory
instead of inclusion into the Winter Weather Advisory. While most
of the snow wraps up late Tuesday, winds will still be breezy and
could make for some blowing and drifting snow. More widespread
gusts of 25-45 mph return Tuesday evening into early Wednesday
morning and this will usher in the colder air. We will be watching
for wind chills to drop well below zero for most of the area
Tuesday night into Wednesday with some of the coldest areas in the
-10 to -20 degree range. AMM

.LONG TERM...Wednesday through next Monday. The long-term periods
begin in a familiar pattern: a split upper low centered near the
Four Corners Area. With ridging building into WA/OR, we should see
cold and dry conditions across southeast Idaho through the rest of
the work week. There is a potential for valley fog/stratus given the
presence of the upper ridge, particularly Thursday morning with the
ridge axis over western Idaho. Temperatures are expected to dip
below zero Wednesday morning in the Upper Snake Plain and Teton
Valley. Wind chills could be a factor as strong downslope winds loom
along the Divide. Winds are expected to taper off throughout the day
Wednesday with the return of high pressure. The upper ridge axis is
expected to shift eastward on Friday as another split upper low
evolves off the CA Coast. The forecast remains dry as we head into
the weekend, but we may see a slight chance of mountain snow
Saturday with the northern stream trough. Snow chances increase on
Sunday as a shortwave dips into the trough. By Monday, temperatures
should be back to near normal. Hinsberger

&&

.AVIATION...A strong weather system will move through the area
tonight, bringing snow and winds to most of southeast Idaho.
Strongest winds will be at BYI with gusts to 40kts possible, though
snow accumulation will only amount to a dusting. BYI may briefly drop
below VFR tonight. Best snow and blowing snow chances will be at IDA
and DIJ, and have included IFR VIS at those sites. Otherwise, we'll
see MVFR conditions throughout the snow event at PIH. Hinsberger

&&

.AIR QUALITY...An Air Quality Advisory is in effect for Franklin
County through Tuesday afternoon due to degraded air quality. The
AQI is currently moderate category as low-level inversions persist
with little mixing expected. Conditions are expected to deteriorate,
and is forecast to be in the "Unhealthy for Sensitive Groups"
category. A cold front will sweep through late tonight, and will
help lift the low-level inversions and potentially improve air
quality. Hinsberger

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 5 PM this afternoon to 11 AM MST Tuesday for
IDZ051-055.

Winter Weather Advisory from 8 PM this evening to 11 PM MST
Tuesday for IDZ053-054-058-062>064.

Winter Weather Advisory from 5 PM this afternoon to 11 PM MST
Tuesday for IDZ056.

Wind Advisory from 5 PM this afternoon to 5 AM MST Wednesday for
IDZ057.

Winter Weather Advisory from 11 PM this evening to 11 PM MST
Tuesday for IDZ060.

Winter Weather Advisory from 5 PM this afternoon to 5 AM MST
Wednesday for IDZ066-067.

&&