128
FXUS65 KRIW 092317
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
417 PM MST Sun Nov 9 2025

.KEY MESSAGES...

- Warm and dry today through Thursday, with temperatures 10 to
  15 degrees above average and breezy winds winds expected in
  the afternoon hours.

- Increasing precipitation chances come Friday and into the
  weekend.

&&

.UPDATE...
Issued at 1141 AM MST Sun Nov 9 2025

No notable changes with this update. This week is dominated by high
pressure. It is not until late Thursday that the next notable system
moves into the area. Daily high temperatures remain above normal,
with breezy afternoons for usual locations.

The ridge flattens a little late Monday into Monday night, which
also brings a bit of moisture. Main "impacts" from this are
increasing clouds over the area, namely northern Wyoming. There
could be just enough moisture to squeeze out a very light shower
over the Bighorn Basin and Bighorn Mountains (10% chance).

&&

.DISCUSSION...
Issued at 1205 AM MST Sun Nov 9 2025

WV/IR imagery shows mainly cloudless skies across the CWA with
ridging evident to the west. This upper level ridge will
continue to build in Sunday and into the early part of the work
week with increased convergence aloft. With surface high
pressure and light winds to go along with the clear skies, there
is a low (<10%) chance for patchy fog across some of the areas
in Jackson Hole and northern Bighorn Basin/Johnson County. With
such a dry airmass, confidence low at this point but there is a
hint with the short term model data to occur by sunrise Sunday
morning.

Otherwise, expect a pleasant Sunday to be had with seasonable
temperatures and relatively light winds. Warming and dry trend
continues into the new work week with the aforementioned upper
level ridge/surface high pressure set in place through mid
week. Temperatures 10 to 15 degrees above average expected with
breezy winds as well due to the stronger daytime heating and
mixing element. This ridge will start to breakdown into Thursday
and push east Friday. This will give way to an upper level low
currently in the GOA to push near the Pacific northwest coast
opening back up the westerly, moisture rich flow for points west
of the Divide. Precipitation chances increase as a result for
Friday and especially into the weekend. Details not concrete at
this time with timing and amounts, but western mountain snow and
valley rain probable not expecting it to push east of the
Divide at this point in time. Stay tuned for updated forecasts
in the coming days.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 416 PM MST Sun Nov 9 2025

Cirrus will begin to increase later tonight and will vary between
SCT to BKN through the day Monday. This will still hold well above
VFR thresholds across the state through the next 24 hours. Any wind
gusts Monday will be limited to KCPR, where gusts around 35kts will
be persistent through the day.

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

&&

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

&&

$$

UPDATE...Wittmann
DISCUSSION...Lowe
AVIATION...Straub