304
FXUS65 KRIW 311840
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1240 PM MDT Sun Aug 31 2025

.KEY MESSAGES...

- An isolated storm is possible (10%-15%) over the Bighorn,
  Absaroka, and Wind River Mountains this afternoon.

- Smoke from wildfires will be across the area today and
  tomorrow.

- Dry Sunday through Tuesday. Temperatures are seasonal, with
  highs in the upper 70s to upper 80s.

- A cold front drops highs by up to 5 degrees on Wednesday and
  Thursday. This also brings low chances (15%) for showers and
  storms Wednesday afternoon, with better chances Friday into
  next weekend.

&&

.UPDATE...
Issued at 1235 PM MDT Sun Aug 31 2025

No major changes to the forecast with this update. Today should be a
nice day to be outside, with highs in the upper 70s west of the
Divide and low-to-mid 80s east. Overall, the area remains dry, with
a few showers possible (15%-25%) over the Bighorn and Wind River
ranges this afternoon. Tomorrow (Labor Day) looks very similar, with
high temperatures trending a few degrees warmer. Again, a few
showers will be possible over the mountains, with models mainly
highlighting the southern Absarokas and northern Bighorns.

&&

.DISCUSSION...
Issued at 130 AM MDT Sun Aug 31 2025

Conditions are expected to be mostly dry for the rest of the Labor
Day weekend and Tuesday, with temperatures ranging from the upper
70s to upper 80s. There is less than a 10% chance for showers to
develop over the Bighorn, Absaroka and Wind River Mountains this
afternoon. Winds will stay light, with periods of high clouds from
time to time. The synoptic pattern this week remains largely
unchanged: the Cowboy State will be sandwiched between an upper
level ridge to the west and a strong developing longwave trough to
the east. The influence of these two features could cause some
variability for each side of the Divide. The main wrinkle today
will be increasing smoke/haze across western and central
portions of the CWA through the day. Most of the smoke will be
from the numerous wildfires in central ID.

A cold front looks to move across areas east of the Divide by
Wednesday. Models are now in better agreement with the timing and
keep the colder air well to the east. The possibility for the first
shot of fall weather has gone down and does not look like it will
happen this week. Overall, the forecast looks to stay somewhat
stable this week with mostly dry conditions and light winds.
Additionally, these conditions will keep fire weather conditions
from going critical.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1111 AM MDT Sun Aug 31 2025

A ridge axis to the west of Wyoming keeps the weather quiet over the
next 24 hours. All terminals to be VFR with only a few mountain
cumulus across the northwest and northern mountains. KCPR sees
a west to northwest wind 9-12kts Sunday afternoon, otherwise
wind speeds to be 8kts or less at all other terminals.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Wittmann
DISCUSSION...LaVoie
AVIATION...CNJ