833
FXUS65 KPIH 200401
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1001 PM MDT Tue Aug 19 2025

.KEY MESSAGES...

- Highs this afternoon still expected to approach records.

- Weak moisture will be available for isolated dry thunderstorms
  Wednesday, otherwise dry and warm conditions continue.

- Deeper moisture arrives for increasing thunderstorms chances
  beginning Saturday and continuing into next week.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 206 PM MDT Tue Aug 19 2025

Satellite imagery continues to show deep trough off BC Canada coast
with high pressure centered across the southern Rockies/Four Corners
region. Smoke plume that transected the region overnight has shifted
off into WY late this morning. Weak areas of shallow cu building
across the central mountains this afternoon, generally west of US 93
ahead of weak shortwave ejecting northeast through Oregon this
afternoon. Still some potential for isolated thunderstorm
development across the Frank Church, but generally further north
closer to the MT border. Anything that can develop will remain
generally dry with little precipitation expected. Elsewhere,
conditions remain very dry with temperatures already in the upper
80s and lower/mid 90s across a wide swath of lower elevation areas,
and several more hours of daytime heating to go. Temperatures
tonight remain quite warm for areas along the Snake River and
valleys to the south, leading to localized regions of enhanced Heat
Risk, especially with temperatures on Wednesday expected to remain
warm in the lower/mid 90s. Will continue to forego a Heat Advisory
at this time. Additional plume of moisture trying to work north
along the Nevada/Utah border toward Idaho may be enough to help
produce isolated thunderstorm development across East Idaho
Wednesday. Best chances are likely across the Snake Plain and
southern/eastern highlands during the day, but maintained just
enough PoP to produce mention across the entirety of the forecast
area tomorrow. Once again, moisture remains extremely limited for
thunderstorm development, so anything that does develop should
remain on the dry side with little precipitation realized.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 206 PM MDT Tue Aug 19 2025

Expecting dry and warm conditions Thursday and Friday as upper level
ridge re-establishes itself over Idaho.  High in the 70s and 80s
mountains and upper 80s to lower 90s valleys on Thursday.  It will
be even warmer Friday with highs in the 90s valleys and 80s
mountains.  Long term models showing monsoonal moisture returning to
southeast Idaho with a chance for showers in the southern mountains
Saturday and across the entire region Sunday through Tuesday.  After
a very dry summer it would be welcome to see some rain over
southeast Idaho and long term grids showing this possibility but at
this point rainfall amounts are forecast to be mainly light across
the region with the southern mountains receiving the brunt of the
precipitation.  Highs are expected to cool to the 80s low elevations
by early next week and 70s to lower 80s mountains.  No wind impacts
outside of thunderstorm activity is expected  in the long term
period.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1000 PM MDT Tue Aug 19 2025

High pressure will bring VFR conditions through the period.
Expect some mid level clouds into tomorrow with moisture moving
in South Southwest flow aloft. Winds will gust up to around 15
to 20 kts for IDA, PIH, and SUN (and maybe DIJ) tomorrow
afternoon.

&&

.FIRE WEATHER...
Issued at 206 PM MDT Tue Aug 19 2025

Weak impulse rotating around large trough in the Pacific may be
enough to produce isolated thunderstorms across the northern half of
zone 475 this afternoon, otherwise dry conditions are expected.
Temperatures remain very warm today with localized triple digit
temperatures along with widespread single digit and low-teen
humidities this afternoon. Poor recovery tonight will lead into
another very warm day on Wednesday, though slightly cooler than
today with lower elevation highs only in the lower to mid 90s.
Additional moisture may be able to work north into East Idaho for
isolated thunderstorm potential across all of East Idaho, though the
best chances look to be across the Snake Plain, Caribou NF and
Southern Sawtooth NF regions. High pressure rebuilds across the
region for Thursday into Saturday with a return to drier humidities.
There is a potential for moisture to work around the high pressure
into East Idaho this weekend, with increasing chances for showers
and thunderstorms beginning Sunday.

&&

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

&&

$$

SHORT TERM...DMH
LONG TERM...GK
AVIATION...TW
FIRE WEATHER...DMH