931
FXUS65 KPIH 231132
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
532 AM MDT Fri May 23 2025

.KEY MESSAGES...

- Slight chance of showers and thunderstorms in the mountains
  and highlands for Friday afternoon and evening.

- Slight chance of showers and thunderstorms Saturday afternoon
  for the eastern and southeastern highlands.

- Dry and warming through Memorial Day in the Snake River plain
  and eastern Magic Valley.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 250 AM MDT Fri May 23 2025

Today will not be quite an exact repeat of Thursday, but close
to it! Think of it as Thursday-lite. Winds will be lighter over
all and any shower or thunderstorm activity will be even more
confined to the Central Mountains and Eastern Highlands/Island
Park areas. We`ll see these as a weak shortwave passes through
later this evening/early Saturday. Look for gusts with any storm
to be around 40 mph, though a rogue gust closer to 50 isn`t
totally out of the question. Winds will pick up a bit tonight
with gusts around 25 to 30 mph as the shortwave passes through
Eastern Idaho. Highs this afternoon return to the low to mid 70s
throughout the eastern Magic Valley and Snake River Plain with
mid to upper 60s in the mid elevations. Our warming trend will
continue into the holiday weekend with highs on Saturday being
about 3 to 5 degrees cooler. Saturday will be a mostly dry day
for many, but we keep around a 20 percent chance of a few
showers or storms in the Eastern and Southeastern Highlands.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 250 AM MDT Fri May 23 2025

High pressure will continue to prevail across eastern Idaho to
finish out Memorial Day Weekend with highs in the 70s/80s as
conditions remain predominantly dry with plenty of sunshine. As
a 500 mb trough to the south works east over the Continental
Divide on Sunday, a ridge of high pressure will continue to
build in from the west, bringing warmer temperatures and dry
conditions outside of some isolated showers and thunderstorms in
the higher terrain, primarily east of Interstate 15. For
Memorial Day, dry conditions will continue through much of the
day as our next 500 mb trough begins to build into the Gem State
with isolated showers and storms possible during the afternoon
and evening hours, mostly in the higher terrain. This system
will help knock down temperatures by a few degrees for Tuesday
courtesy of increased cloud cover and as it continues its
progression east, support another round of diurnal showers and
storms.

That aforementioned ridge of high pressure looks to regain some
ground for Wednesday and Thursday, leading to temperatures
trending a bit warmer with highs about 10-15 degrees above
normal for late May in the 70s to mid 80s as daily, diurnal
showers and thunderstorms remain possible during the afternoon
and evening both days. Deterministic model guidance diverges mid
to late next week as the GFS supports a more active and wetter
pattern with several systems moving overhead while in contrast,
the ECMWF keeps a ridge of high pressure solidly overhead. The
NBM continues to be in the middle of the road of these two,
keeping with the warm temperatures but only supporting isolated
shower and storm potential each day. The NBM also reflects more
closely to GFS/ECMWF ensemble guidance which keeps with an
extended stretch of above normal temperatures and mostly dry
conditions outside of some isolated showers and storms each
afternoon and evening. This looks like the pattern we will keep
around to finish out May into early June with above normal
temperatures and near normal to below normal precipitation
expected in the latest CPC 6 to 10 and 8 to 14 Day Outlooks.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 530 AM MDT Fri May 23 2025

Predominant VFR and dry conditions with light winds will
continue across eastern Idaho today with another round of
isolated showers and thunderstorms possible further north this
afternoon and evening. Best chances will exist in the Central
Mountains and Montana border/Island Park region with a 10-20%
chance at KSUN and less than a 10% chance elsewhere at other
terminals. With latest model guidance keeping the bulk of
activity north of KSUN, so we will keep with a dry forecast for
now as we continue to evaluate the potential. Clear skies will
start off the day ahead of increasing mid/upper-level clouds
building in by midday which will persist overnight tonight.

&&

.FIRE WEATHER...
Issued at 250 AM MDT Fri May 23 2025

Like yesterday, we`ll keep around some showers and
thunderstorms throughout Fire Weather Zones 411, 475, and 476 as
a weak shortwave passes through Eastern Idaho late today/early
Saturday. Any wind gusts with storms today would be closer to 40
mph and gusts outside of storms will pick up to around 25 to 30
mph at times. Parts of Zone 413 will see about a 20 percent
chance of a shower or storm as we get into Saturday.
Temperatures continue their warming trend through the holiday
weekend with dry conditions through the eastern Magic Valley and
Snake River Plain.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...AMM
LONG TERM...MacKay
AVIATION...MacKay
FIRE WEATHER...AMM