321
FXUS65 KPIH 180612
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1212 AM MDT Mon May 18 2026

.KEY MESSAGES...

- Gusty northerly winds diminishing later on today

- Best chance of precipitation today across the southeast corner

- Frost/freeze conditions through at least midweek before
  temperatures begin warming up

&&

.DISCUSSION...
Issued at 1209 AM MDT Monday May 18 2026

Strong low pressure will continue slowly churn to our south and
east today. This will keep a persistent area of light rain and
snow, with a few thunderstorms possible across the southeast
corner. We could see snow falling at lowest elevations but
anything that falls and accumulates should melt later in the
day. Across the the higher elevations, a couple of inches are
possible. We should also see a few showers across the central
mountains south across the Magic Valley and Albion Mountains
during the afternoon and evening hours. The bigger overall issue
is strong northerly winds, which should be peaking early this
morning, but lingering through the day. We do expect some spots
to exceed the low end for WIND ADVISORY, but those pocket should
be small enough to keep us from issuing something. That said, we
are going to easily exceed the northeast wind threshold for
American Falls Reservoir, therefore we will keep the LAKE WIND
ADVISORY in place for today. The other issue is colder
temperatures. We do have a FREEZE WARNING and FROST ADVISORY out
for the Snake Plain and Magic Valley this morning. At the
moment, the wind is helping keep temperatures pretty warm.
However, we are seeing colder air slipping across the Montana
border. That, in conjunction with the usual drop in temperatures
overnight, we see no need to end the headlines in place for this
morning. For tonight, with less wind, we are likely in line for
another round of Frost/Freeze headlines. We will also have less
cloud cover around. Highs today barely top out above 60 in a few
spots.

We should see a few showers and potentially isolated storms
closer to the Montana border Tuesday afternoon and evening. At
the moment, this may be a simple round of virga/sprinkles, but
certainly worth mentioning in the forecast. Another wave drops
south and east for a better chance of precipitation and
thunderstorms Wednesday night and Thursday. We may see a few
showers and storms daily heading into the weekend especially
closer to the Montana border. Temperatures do eventually
starting warming up, heading actually toward AVERAGE through
midweek and ABOVE AVERAGE later in the week, as we switch from
north/northwest flow to southwest flow.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1018 PM MDT Sun May 17 2026

VFR conditions are expected at most sites through the period. DIJ
is the one exception where CIGs/VIS have been borderline
MVFR/VFR so far. Borderline MVFR/VFR conditions are expected to
continue for DIJ. Conditions are forecast to remain dry at BYI,
PIH, and IDA with VCSH remaining in the forecast for SUN and
DIJ.  Any showers at DIJ are expected to turn to snow after
around 5z, which would bring a better chance of MVFR CIGS/VIS.
Northerly winds behind the cold front will also increase tonight
with gusts around 20-25 kts at DIJ, SUN, and BYI and closer to
35 kts at PIH and IDA. Winds will drop off by around 10kts after
around 9 to 12z before ramping back again by late morning/early
afternoon. Winds look to start dropping off gradually overall
by around 20 to 21z for all TAF sites. Expect mostly clear skies
by early to mid afternoon for all TAF sites. Wind drop off below
10 mph by early evening tomorrow evening.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 3 AM to 9 AM MDT Monday for IDZ051-052.
Frost Advisory from 3 AM to 9 AM MDT Monday for IDZ053>055.
Lake Wind Advisory from 6 AM to 9 PM MDT Monday for IDZ054.

&&

$$

DISCUSSION...Keyes
AVIATION...TW