American Falls, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

937
FXUS65 KPIH 040341
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
941 PM MDT Sun May 3 2026

.KEY MESSAGES...

- Unsettled conditions return Monday and Tuesday.

- Lake Wind Potential Tuesday.

- Another round of Frost/Freeze Wednesday AM.

&&

.DISCUSSION...
Issued at 1252 PM MDT Sun May 3 2026

Satellite imagery shows split flow pattern with deep low off
California coast and shortwave dropping through Montana in
northern stream flow. There is still a low chance of seeing
isolated convection this afternoon across higher elevation
areas, but surface dew point depressions are quite low.
Confidence leans toward virga showers with an occasional
sprinkle this afternoon and early evening. Split flow collapses
slightly into Monday as coastal low shifts inland slightly and
starts to open, allowing moisture to pull north into East Idaho.
Thunderstorm activity increases, especially across the southern
highlands. Sounding profiles look favorable for gusty winds
with potential for brief moderate rainfall, though most areas
will see little precipitation.

Shortwave feature for Tuesday drops frontal boundary south
across the forecast area early in the day. Showers and isolated
thunderstorms continue mainly over higher terrain. Slightly
cooler temperatures and gusty northerly flow will be in place.
For winds, blended above NBM deterministic towards the 75th
percentile, keeping forecast below general Wind Advisory
criteria. But, a Lake Wind Advisory will likely be needed for
American Falls Reservoir, with rough chop piling up at the south
end near the dam under the influence of the northerly winds.
Another night of frost/freeze is looking more confident as NBM
probabilities support more than 50% chance of overnight lows
dropping below freezing for the northern portions of the Snake
Plain Tuesday night/Wednesday morning. It does look like a one-
and-done cold snap as upper ridge rebounds for the remainder of
the week with a return to a warming trend and a greater than 50%
chance of several areas meeting or exceeding 80 degrees for
highs by Friday. GFS and ECMWF models this morning continue to
show shortwave pushing through the PacNW and across Montana late
Friday into the weekend, collapsing the ridge and reintroducing
unsettled conditions to East Idaho for the weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 941 PM MDT Sun May 3 2026

VFR conditions will continue throughout tonight and most of Monday.
Very little cloud cover will be found tonight, but it will begin to
increase on Monday. Shower and thunderstorm chances will increase
Monday afternoon into the evening as we get more influence with
general troughing over the area as a low moves to our south. Given
that we have a low, but widespread chance of showers and
thunderstorms at all TAF sites except BYI tomorrow, have added more
PROB30 or VCSH with this issuance. Max wind gusts with a storm look
to be around 30 kts.

&&

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

&&

$$

DISCUSSION...DMH
AVIATION...AMM