150
FXUS65 KPIH 242330
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
530 PM MDT Sun Aug 24 2025

.KEY MESSAGES...

- Smoke from regional wildfires continues today, and forecast may
  not be fully representative with recent new fire activity.

- Deep monsoonal push starts to arrive today, and continues through
  Thursday.

- Isolated showers and thunderstorms across the south today
  become more widespread through Thursday. Cooler temperatures,
  increased humidity, and measurable rainfall is expected for
  most areas this week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 141 PM MDT Sun Aug 24 2025

Satellite imagery shows deep moisture rotating around the high
pressure over the desert southwest. Radar imagery shows band of
showers moving north from northern Nevada/Utah this afternoon, along
with weak thunderstorms near Bear Lake. Recent CAM runs slowly shift
convection further north through the remainder of the afternoon, and
also fire some activity across the central mountains. Believe most
of the precipitation will stay light but localized heavy rain will
be possible as the moisture profiles continue to increase today.
Trend continues into Monday with isolated very light showers
continuing overnight into Monday morning, then thunderstorm activity
increasing during the afternoon. With PWAT values increasing to
between 0.75 and 1.0 for a significant portion of the forecast
area by Monday afternoon, locally heavy rainfall is expected,
especially across the southern highlands where moisture profiles
are deepest. There is potential concern for localized flooding
in steep terrain and near burn scars, but will hold off on any
messaging for now, since the deepest moisture arrives later in
the week.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 141 PM MDT Sun Aug 24 2025

The monsoon event will be in full swing during the extended
timeframe as shower and storm coverage gradually increases heading
into mid-week. Precipitation will overspread Southeast Idaho come
later Tuesday into Wednesday, with widespread PoPs ranging 65 to 95
percent through Thursday. National Blend 48 hour model mean
precipitation totals largely range half an inch to one inch. Locally
moderate to heavy rain may accompany stronger, slower-moving, and/or
training thunderstorms, which could lead to locally higher totals
well above an inch and localized flooding. The Weather Prediction
Center has included the entire CWA in an Excessive Rainfall Outlook
Tuesday through Thursday. Synoptic winds will be fairly mild
throughout the period, with gusts to around 20 mph and thunderstorm
outflow winds ranging 30 to 40 mph. Temperatures will run below
climatological norms throughout the extended, reaching as low as 10
to 15 degrees below normal on Wednesday before very gradually
warming back to near normal by early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 523 PM MDT Sun Aug 24 2025

Monsoonal moisture pushing into southeast Idaho at long last and
that is going to be the major impact this week. Have vicinity
showers at all sites this evening as well as some possible
visibility restrictions in smoke at SUN and PIH but should stay
6 miles or above. For Monday brought in prob 30 thunderstorm
chances at all sites after 20Z. Conditions will get wetter as we
go through Tuesday and Wednesday.

&&

.FIRE WEATHER...
Issued at 141 PM MDT Sun Aug 24 2025

Pattern change is imminent with arrival of deeper moisture beginning
today and increasing into Monday. Isolated showers and thunderstorms
mainly across the South Hills and Southeastern Highlands today
expands further north Monday afternoon, and covers almost the
entirety of the district by Tuesday. Humidities climb significantly
during this time period, bringing much needed relief to the very dry
conditions, and temperatures cool for this time as well. Rainfall
transitions from a mix of wet and dry today to wet, possibly very
wet at times by Tuesday. All of East Idaho remains in a Marginal
Risk for Excessive Rainfall Tuesday through Thursday, meaning a
roughly 5 percent chance of localized extremely heavy rainfall.

&&

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

&&

$$

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