417
FXUS65 KPIH 161928
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
128 PM MDT Sat May 16 2026

.KEY MESSAGES...

- Breezy Conditions: Wind Advisory today for the Snake River
  Plain, eastern Magic Valley, Arco Desert, and Shoshone area
  for sustained winds 25 to 35 mph and gusts to 50 mph.

- Another Drastic Temperature Swing Coming: Temperatures
  tomorrow will struggle to reach the mid-40s to mid-50s.

- Frost and Freeze Risk: Freeze Warning in effect for our
  growing zones tonight, with hard freeze possible in areas.
  Similar temperatures are expected Monday and Tuesday mornings.

&&

.DISCUSSION...
Issued at 128 PM MDT Sat May 16 2026

Satellite water vapor imagery this afternoon reveals a broad,
shallow trough axis shifting across the Pacific Northwest, with
a distinct shortwave axis pushing through east Idaho ahead of
the parent circulation center over central Washington. Under
extensive cloud cover, unseasonably cool temperatures remain
entrenched across the region today. A few light showers are
possible through this evening, primarily restricted to zones
bordering southwest Montana where precipitation amounts will be
heavily limited. Model guidance is in good agreement that the
main circulation center will track southward from Washington
into northern Nevada overnight into early Sunday morning. While
gusty daytime winds will ease over the lower elevations tonight,
cold air will settle into the region as the upper core shifts
overhead. A WIND ADVISORY remains in place today, with the
strongest winds across the Arco Desert.

High confidence of freezing temperatures continues overnight
tonight, and the FREEZE WATCH has been upgraded to a FREEZE
WARNING for the entirety of the Snake Plain. For a large
portion of the warning area, low temperatures will bottom out
between 27-32 degrees. However, probabilistic ensembles suggest
a 40-60% chance that localized areas from Craters of the Moon
northeastward to Mud Lake could experience a hard freeze at or
below 28 degrees. Along the interstate corridor between Burley,
Pocatello, and Idaho Falls, overnight lows remain marginally
above freezing, limiting the potential for freeze although frost
will still be possible. On Sunday, a tightened northerly
surface pressure gradient will overspread the region. This will
elevate wind speeds sufficiently to warrant a LAKE WIND ADVISORY
for the American Falls Reservoir, where choppy water is
expected to increase near the dam.

Unsettled weather will linger over the higher terrain tonight
into Sunday, but the most cohesive period for widespread
precipitation arrives late Sunday night into Monday morning. As
the upper low migrates eastward through Utah, overrunning
moisture will interact with the cold air mass, supporting a
transition to snow down to valley floors across the southern and
southeastern highlands. Total snow accumulations of 2 to 6
inches are expected across the Bear River Range and areas
stretching east to the Wyoming border, with generally less than
an inch elsewhere. Sub-freezing overnight lows will persist
through Tuesday morning, making additional frost and freeze
headlines highly likely for early next week. Ensemble solutions
continue to struggle with the details in the slowly departing
trough. Occasional mainly higher elevation showers remain
possible through the week, but the overall trend still supports
temperatures moderating through the week. Overnight lows should
recover above freezing for most areas for Wednesday morning and
beyond.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1125 AM MDT Sat May 16 2026

Wind continues to be the biggest impact at our sites today with
afternoon gusts to 20-25 kts at SUN and DIJ and 25-35 kts at
BYI, PIH, and IDA. This comes as a trough is moving into the
area today and passing directly through on Sunday and Monday.
Cloud cover has been on the increase as a result, and while
there is a very small (10-15%) chance of a few sprinkles at DIJ
this afternoon, the probability is not high enough to put into
the TAF at this time. Precipitation chances will increase for
SUN and DIJ on Sunday as the trough really begins drop southward
into eastern Idaho as we remain breezy.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 10 PM MDT this evening for IDZ051>055.
Freeze Warning from 3 AM to 9 AM MDT Sunday for IDZ051>055.

&&

$$

DISCUSSION...DMH
AVIATION...AMM