436
FXUS65 KPIH 280845
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
245 AM MDT Mon Sep 28 2026

.KEY MESSAGES...

- Showers East of I-15: A brief round of showers and isolated
  thunderstorms today primarily along and east of the I-15
  corridor, focusing over the Eastern Highlands.

- Noticeably Cooler Today: Showers exit rapidly today with
  clearing skies. Post-frontal air will drop valley daytime
  highs into the 60sroughly 10 degrees cooler than yesterday`s
  readings.

- Early October Warming Trend: High pressure builds over the
  Intermountain West starting Wednesday, keeping the remainder
  of the 7-day forecast completely dry while pushing lower-
  elevation highs into the mid-to-upper 70s by late week.

&&

.DISCUSSION...
Issued at 243 AM MDT Mon Sep 28 2026

Upper-level trough will continue shifting eastward today, with
showers and isolated thunder across eastern Idaho through this
evening. Expect a 10 degree cooldown for many locations between
yesterday`s daytime temperatures and today`s, with highs only
warming into the 50s and 60s for much of the forecast area. Models
suggest high pressure building in from the west beginning Tuesday,
remaining in control of the pattern through the end of the extended
timeframe. This will mean dry conditions for the next week and
gradual warming. Daytime temperatures will warm into the low to mid-
70s across low elevations by Thursday with some locations likely
reaching 80 degrees by early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1014 PM MDT Sun Sep 27 2026

VFR conditions will likely continue at all sites through the
forecast period. Moisture spreading into the region will allow
for -SHRA/SHRA to develop across the region this evening around
midnight. With any heavier showers, MVFR conditions are
possible. The best chances for predominate -SHRA/SHRA will be
at DIJ, PIH, and IDA this evening into early morning, but carry
VCSH at all sites. Have kept PROB30 for -TSRA for DIJ, PIH, and
IDA for this evening around midnight. However, -TSRA is not
that likely. Precipitation shifts east of the region during the
morning Monday. Expect a break in precipitation by early to mid
morning with another chance of showers for PIH, IDA, SUN, and
DIJ tomorrow afternoon. Have kept in VCSH for PIH, IDA and SUN
for tomorrow afternoon. There is a slight chance of
thunderstorms tomorrow afternoon as well. Have added predominate
showers and a PROB30 for -TSRA for DIJ for tomorrow afternoon.
Other sites may need a PROB30 for thunderstorms for tomorrow
afternoon as well.

&&

.FIRE WEATHER...
Issued at 243 AM MDT Mon Sep 28 2026

Upper-level trough will continue shifting eastward today, with
showers and isolated thunder across eastern Idaho through this
evening. Activity will favor the east and southeast highlands.
Expect a 10 degree cooldown for many locations today, with highs
only warming into the 50s and 60s for much of the area. A weak ridge
will build in from the west beginning Tuesday and remain in control
of the pattern through the beginning of next week. This will mean
dry conditions and gradual warming. Daytime temperatures will warm
into the low to mid-70s across low elevations by Thursday with some
locations likely reaching 80 degrees by early next week.

&&

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

&&

$$

DISCUSSION...Cropp
AVIATION...TW
FIRE WEATHER...Cropp