962
FXUS65 KPIH 171016
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
416 AM MDT Sat May 17 2025

.KEY MESSAGES...

- Frost Advisory in effect for portions of Eastern Idaho from 2
  to 8 AM Saturday.

- Another potent low pressure system expected for the weekend
  bringing more rain/storms and cold temperatures Sunday after
  milder temperatures today.

- Gradual improvement expected early next week with a warmup
  likely mid/late next week.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 158 AM MDT Sat May 17 2025

The much advertised rainy weekend has finally arrived and not
much has changed with the forecast thinking for what lies
ahead. Early morning satellite imagery shows cloud cover quickly
streaming in from Oregon and western Idaho in association with
a deep upper level trough that will move over the region later
today. Clouds will be on the increase towards daybreak with
precipiation likely reaching our area by late morning across the
central mountains with the rest of the area seeing precip by
the early afternoon. Southerly flow aloft will allow
temperatures to reach the mid/upper 60s in the lower elevations
by mid afternoon which should give us enough instability to
support thunderstorms potential regionwide. Gusty winds would be
the primary concern with any thunderstorms but some small hail
is certainly possible as well.

The clouds and precipitation will stick around into the second
half of the weekend as a closed upper low will sweep down
through the upper trough across the Gem State during the day and
towards daybreak Monday. As this feature moves overhead,
temperatures will be well below normal for the day Sunday with
highs mainly in the 40s but areas in the Snake Plain/Magic
Valley MAY be able to reach the lower 50s but not by much.
Thunderstorm chances will be more limited on Sunday but can`t be
ruled out entirely. Synoptic winds do look to increase on
Sunday which may require the need for a Wind Advisory across the
Magic Valley, Shoshone, the south hills and into the Raft River
region but stay tuned on that. &&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 158 AM MDT Sat May 17 2025

As the work week begins, the upper low shifts down towards the
Four Corners area while its energy appears to get absorbed by a
much larger low developing across the northern Plains States.
What that means for us locally is gradually improving conditions
over the course of the day on Monday. It`ll still be on the
cool side with 40s and 50s commonplace for daytime highs but
we`ll see gradual clearing throughout the day along with slowly
dwindling precipitation. On Monday, most of the precip will
likely be limited to areas in the eastern highlands areas
further west will already begin to see clearing.

Tuesday will be the first day where ample sunshine becomes more
prevalent and with weak ridging building overhead, temperatures
will respond accordingly by warming closer to normal values and
continue on that upward trajectory throughout the rest of the
work week. Low to mid 70s appear likely across the lower
elevations as we get into the middle to late part of next week.
Some weak shortwaves moving through the upper flow aloft MAY
help produce some additional cloud cover and isolated/scattered
PoP chances but mainly across the northern portions of the
forecast area.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 416 AM MDT Sat May 17 2025

VFR conditions this morning will gradually deteriorate
throughout the day as a prolonged period of cloudy, rainy
weather is expected throughout eastern Idaho as an upper level
trough swings through the region. Precip will likely begin
around KSUN later this morning and then overspread the remainder
of regional terminals by the time we get into the early
afternoon. When this occurs, CIGs will gradually lower gradually
reaching MVFR levels by mid/late evening, potentially lower,
with any prolonged moderate/heavy showers/storms. Speaking of
the latter, do expect some thunderstorms across the area today
so PROB30s remain in place. Winds will likely pick up during the
overnight and into the first part of the day Sunday, especially
around KBYI but the windiest period is likely just beyond the
current 12Z forecast period.&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM MDT this morning for IDZ051>054.

&&

$$

SHORT TERM...McKaughan
LONG TERM...McKaughan
AVIATION...McKaughan