996
FXUS65 KPIH 031900
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
100 PM MDT Wed Sep 3 2025

.KEY MESSAGES...

- Cooler temperatures will starting returning to eastern Idaho

- Isolated thunderstorms possible tomorrow and Friday

- Better chance of rain and thunder expected this weekend

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 1238 PM MDT Wed Sep 3 2025

Monsoon moisture remains more centered to our west, although
some mid and high level clouds are creeping into central and
eastern Idaho. It doesn`t look like we will see any sprinkles or
thunder today, but could see some virga from that. The potential
for any significant wind gusts IF we do see virga today is
basically nothing. The ridge continues to weaken, allowing for a
slow increase in moisture. Isolated thunderstorms are expected
tomorrow across the central mountains, with a few possible
across portions of the Snake Plain and into the southeast
highlands. Anything across the central mountains may be more
influenced by any type of outflow boundaries. With this initial
push, look for very little rainfall. There is a 10-30% chance of
gusts over 35 mph tomorrow with anything that develops. Another
round is forecast Friday afternoon and evening. Interestingly
enough, there might be a "dry push" coming out of
Montana...dropping the potential down a bit vs tomorrow. At this
point, we still think isolated storms will develop across the
central mountains and higher elevations closer to the Utah and
Nevada borders. Again, not much rainfall and gusty winds are
expected. Today was likely the last day we will see more
widespread 80s and lower 90s, as the pattern change will slowly
knock temperatures a few degrees each day.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Issued at 1238 PM MDT Wed Sep 3 2025

A pattern change still looks to be on track for our long term
forecast for Eastern Idaho. By Friday afternoon, the ridge of high
pressure over our area is beginning to be pushed a bit farther east
as an area of low pressure moves into the Pacific Northwest. This
will open the door for a few isolated showers and storms on Friday.
A shortwave ejecting off of that area of low pressure will move
through the ridge over the weekend and bring some scattered showers
and storms with it. This will help cool down temperatures a few
degrees with highs on Friday in the low to mid 80s and falling into
the mid 70s to near 80 degrees for Saturday and Sunday. Storms on
Saturday and Sunday are more likely to produce some mmeasurablerain
with an area-wide 30 to 50 percent chance of at least a tenth
of an inch of QPF from Saturday evening to Sunday evening.
Models are showing a slightly slow-down in the moisture arriving
this weekend compared to previous runs. They are also showing a
speed-up for our next system next week. While models had been
showing a Thursday/Friday arrival, ensemble clusters now showing
about a 50 percent chance of the influence of low pressure over
Idaho as early as Tuesday. So while it looked like we would
have more of a break between rounds of precipitation this
weekend and next week, that break may be much shorter. We will
have to see how models continue to handle this over the next few
days. &&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1046 AM MDT Wed Sep 3 2025

We are still looking at VFR conditions even some increase in
monsoon moisture across the area. We still can`t rule out any
virga, but the potential of stronger downburst winds is still
at best 10%...especially tomorrow. Any smoke that continues to
pour into the area doesn`t appear to be producing any visibility
issues, but we could see that change especially if new fires in
our area flare up.

&&

.FIRE WEATHER...
Issued at 1238 PM MDT Wed Sep 3 2025

Hot and mostly dry conditions will continue today and for many on
Thursday and Friday, too. Min RHs this afternoon will be critical to
near-critical ranging from 10 to 20 percent area wide, but we lack
much wind to warrant any Red Flag Warnings at this time. While many
remain dry Thursday and Friday, isolated storm chances do return to
the forecast for each afternoon as a shortwave passes through the
ridge of high pressure currently over our area and allows monsoon
moisture to work northward. This increase in moisture will bring
afternoon min RHs to around 15 to 20 percent on Thursday and 20 to
25 percent on Friday. These isolated storms are most likely in Fire
Weather Zones 410, 413, 422, and 425 on Thursday and in Zones 413
and 427 on Friday. Showers and storms become more scattered on
Saturday and Sunday with an increasing chance for a wetting rain
through the weekend. The NBM currently shows an area-wide 30 to 50
percent chance of at least a tenth of an inch of QPF from Saturday
evening to Sunday evening. This is about a 12-hour slow down from
yesterday`s models. Models are also speeding up the arrival of our
next round of precipiation next week. While they had been showing an
arrival of next Thursday/Friday, models now show rain and storm
chances nearly each afternoon of next week. We will have to see how
models continue to handle this over the next few days.

&&

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

&&

$$

SHORT TERM...Keyes
LONG TERM...AMM
AVIATION...Keyes
FIRE WEATHER...AMM