211
FXUS65 KPIH 240323
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
923 PM MDT Thu Apr 23 2026

.KEY MESSAGES...

- Additional snow accumulations of 2-4" will impact mountain
  passes in the eastern highland through Friday morning, and
  Winter Weather Advisories remain in effect.

- Windy conditions ease this evening throughout the region, but
  remain breezy Friday. Wind Advisory for gusts around 45 mph
  remains in place through the evening.

- Sub-freezing temperatures are expected tonight, with a Hard
  Freeze possible outside the Interstate corridors. FREEZE
  WARNING for tonight. Hard Freeze expected most areas Friday
  night, and additional FREEZE WARNING will be needed.

&&

.DISCUSSION...
Issued at 146 PM MDT Thu Apr 23 2026

Satellite water vapor imagery this afternoon reveals a complex
upper-level low centered over Alberta, Canada. A secondary
shortwave is currently pivoting southeast through western
Montana, trailing the initial system that exited East Idaho
earlier today. Surface winds remain a primary concern into the
evening, particularly across the southern Snake Plain from
Shoshone to Pocatello. While clearing skies may allow for deeper
mixing and wind gusts approaching 45 mph, the development of
shallow convective clouds within these clear slots is expected
to limit the overall mixing potential. A WIND ADVISORY remains
in effect through early this evening to account for these
localized higher gusts.

Lingering snow showers in the eastern highlands will briefly
taper this afternoon before intensifying tonight as the next
shortwave approaches. Additional snowfall accumulations of 2 to
4 inches are expected, primarily above valley floors, impacting
mountain passes through early Friday morning. High-resolution
guidance suggests the heaviest rates will occur late this
afternoon and evening, specifically for the Big Hole Mountains
and surrounding areas. This activity may extend westward into
the Snake Plain near Idaho Falls and shift as far south as
Blackfoot by early evening. Showers will likely redevelop
overnight and spread across the southern and eastern regions
through Friday afternoon; therefore, WINTER WEATHER ADVISORIES
remain in effect for much of the eastern highlands.

Cold overnight lows remain a concern tonight and into the
weekend. Overnight lows are forecast to drop below freezing for
most areas outside the immediate Interstate corridors tonight,
with a "Hard Freeze" (temperatures at or below 28F) possible in
some areas. A FREEZE WARNING has been issued for the entire
Snake Plain for tonight. Even colder air arrives Friday night
into Saturday morning, where there is a greater than 75%
probability of a widespread Hard Freeze across the Snake Plain,
and additional FREEZE WARNINGS are likely. Broad troughing
associated with the Canadian low will likely persist through
mid-week, maintaining showery conditions and below-average
temperatures. Ensemble clusters show positional differences in
the trough axis draped across the region for much of the next
work week, so there is still plenty of uncertainty regarding
exact temperature and precipitation trends.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 922 PM MDT Thu Apr 23 2026

The backdoor cold front has introduced some interesting questions
mainly affecting the forecast tomorrow. For tonight, showers
are persisting behind the front which will most likely impact
DIJ with IFR conditions and potentially could affect IDA to some
degree although confidence is low if there will be significant
aviation issues. As we move into Friday, models have a difficult
time resolving the winds which now look lighter in many areas.
Potentially even SUN may keep some form of downvalley wind. So,
there are more questions than answers in the TAFs. Most likely
not expecting too many issues tonight, but lots of uncertainty
for Friday.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 3 AM to 10 AM MDT Friday for IDZ051>055.
Winter Weather Advisory until midnight MDT tonight for IDZ060-
063-064-066.

&&

$$

DISCUSSION...DMH
AVIATION...13