478
FXUS65 KPIH 162348
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
548 PM MDT Wed Sep 16 2026

.KEY MESSAGES...

-Showers and thunderstorms increasing Thursday through Saturday

-Heavier precipitation expected across the eastern highlands
 into Lemhi County and southwest Montana

-Cooler temperatures starting Friday

&&

.DISCUSSION...
Issued at 133 PM MDT Wed Sep 16 2026

A closed low along the coast briefly will be cutoff from the
main steering flow along the US/Canada border, eventually
meandering across our area through Saturday. This will bring an
increasing chance of showers and thunderstorms starting
tomorrow, including overnight thunderstorm potential. Through
tomorrow morning, since storms will be more dry vs decent rain
producers, there is a 10-50% chance for gusts over 35 mph,
highest across the southeast highlands. For tomorrow, there is a
40-70% chance for gusts over 35 mph across the Snake Plain,
Magic Valley, and South Hills/Albion Mountains...with peak gusts
approaching 50 mph. Lower chances for those types of gusts are
expected elsewhere. The track of the low will put most of the
precipitation across the eastern highlands, Lemhi County, and
north into southwest Montana. Storm totals outside of those
areas will be anywhere from a couple of hundredths to near 0.30"
over 72-ish hours. Locally higher amounts are possible across
the southeast highlands and portions of the central mountains.
Where heavier precipitation occurs, we are looking at
0.30-0.75", with locally higher amounts along the Montana border
and the Tetons. We wouldn`t be surprised to see a rain/snow mix
on the highest peaks when the low crosses Friday night/Saturday
morning. Ahead of the low, temperatures will top out in the
upper 70s to lower 80s tomorrow for lower elevations. Highs
Friday and Saturday will only manage the mid 60s to mid 70s for
the valleys both days.

We will likely see a few wraparound showers on the backside of
that low for Sunday, with dry conditions to start out next week.
Temperatures warm back up slightly, close to 80 for the warmest
spots. We will need to watch the middle of next week so if the
storm track shifts back to the north enough to bring showers and
storms back into eastern Idaho.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 543 PM MDT Wed Sep 16 2026

Pattern change coming with flow aloft turning southerly with
abundant moisture moving into the region from the south. Have at
least vicinity showers or rain showers on station after 03Z this
evening and then 12Z. Have pro30 thunderstorms at all sites
after 18Z Thursday. Not expecting significant winds through
Thursday but some thunderstorm outflow could be in the 20 to 30
knot range.

&&

.FIRE WEATHER...
Issued at 1227 PM MDT Wed Sep 16 2026

Humidities will begin increasing today as monsoonal moisture
works into the region. Areas across the central mountains could
still see humidities in the 15-25 percent range today while most
of southeast Idaho will see humidities in the 25-35 percent
range. Those values will increase over the next couple days. A
few gusts to 25 mph will be possible across the southern
highlands this afternoon. Wind gusts to 25 mph will become more
widespread on Thursday especially in and around any
thunderstorms. Thunderstorm coverage will flirt with scattered
at times but no fire weather headlines anticipated after
coordination with local fire dispatch offices. Drier weather is
expected for the weekend and into the first part of next week.

&&

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

&&

$$

DISCUSSION...Keyes
AVIATION...GK
FIRE WEATHER...McKaughan