844
FXUS65 KRIW 170910
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
210 AM MST Mon Nov 17 2025

.KEY MESSAGES...

- Cooler and wetter weather finally returns to the Cowboy State
  to start the week.

- Periods of showers are expected throughout the day today with
  wet snow/mixing possible over western and southern WY.

- Showers dissipate this evening with mostly quieter and more seasonable
  weather prevailing over the next few days.

- Increased chances for cooler and more unsettled weather to
  return to the region by the end of the week into the weekend.

&&

.DISCUSSION...
Issued at 207 AM MST Mon Nov 17 2025

Portions of the Cowboy State are finally seeing some more autumn-like
weather after a prolonged period of mild and dry conditions. An
upper level low has made its way north after bringing heavy
rain/snow to parts of the southwestern CONUS. Showers are
currently gradually spreading across the state this morning.
Many locations are seeing rain due to the overall warm nature of
this system. However, colder air is trying to funnel its way
into the region. 700 mb temperatures show this colder air over
parts of western and southern WY this morning. Rain has already
begun to transition over to snow for locations such as Afton and
Pinedale. This colder air is expected to continue to spread
east and north through the morning. However these "colder"
temperatures are still rather tame with values only ranging from
-4 to 0C. So while these temperatures are colder than what we
have seen over the past week or so, its still on the warmer
side. As a result many areas will likely see rain as the
predominate form of precipitation with only the higher
elevations of western and southern WY seeing a transition to
snow during the day Monday. Precipitation is expected to fall
periodically throughout much of the day today as the low makes
its way over then to the east of the state.

Winter Weather Advisories remain in effect across the higher
elevations of western WY such as the Tetons, Gros Ventre, Salt
River, Wyoming, and western Wind River Ranges. Favorable flow will
support enhanced orographics across these locations leading to
snowfall amounts of 6 to 12 inches for elevations around or above
9000 feet. Lesser amounts of a trace to a few inches can be expected
for the lower elevations. Western Basins may see a wet coating of
snow but overall impacts will be minimal. The system makes its way
out of the region this afternoon with a few lingering showers
possible during the afternoon and evening as a result of wrap around
moisture.

A lull in the activity is expected through the middle of the week as
the region sits in the middle of multiple disturbances. Weak ridging
over the region will keep things mainly quiet but a few showers
cannot be ruled out at times. Temperatures for much of the week look
to be more seasonable but still slightly above normal ranging in the
mid 40s to low 50s. Overnight temperatures look to be more
seasonable as well with lows in the upper teens to low twenties west
of the Divide and 20s east of the Divide.

The jet stream looks to have finally woken up and it is looking ever
so more likely that more November-like weather returns to the
state for the second half of the month. The aforementioned jet
stream is looking to ramp up sending one disturbance after
another. Currently, a cutoff low is expected to develop and fill
in over the southwestern CONUS for the next few days. Due to a
lack of forcing this low looks to stagnate over that region
until something can help push it east. That push looks to arrive
by the second half of the week in the form of another
disturbance digging south across the western CONUS. The impacts
that may be seen across the state as a result of these
disturbances remains highly uncertain at this time. Models vary
greatly in regards to the track and exactly what the interaction
between these two lows will look like. Overall, there is an
increased likelihood for cooler and more unsettled weather by
the second half of the week into the weekend but at this time
the exact details remain foggy.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 945 PM MST Sun Nov 16 2025

An upper level low is now over UT as it continues to track
northeast into southern WY by 12Z. An area of showers continues
to make its way northward ahead of the low and is expected to
cross the Continental Divide by the start of the forecast. MVFR
to IFR conditions will be widespread west of the Divide, with a
20% chance for LIFR conditions through 15Z. Conditions will drop
to MVFR east of the Divide (mainly for KCPR, KRIW and KLND)
through 12Z. Temperatures favor light snow developing across
southwest Wyoming early Monday morning before transitioning back
by 16Z. A 700mb circulation is set to move over central Wyoming
between 09Z and 15Z. This leads to a period of enhanced
precipitation before downsloping northwest flow arrives by
midday Monday. The northwest flow allows for improving
conditions between 16Z and 21Z at terminals west of the
Continental Divide and around 22Z/23Z at KRIW and KLND. MVFR
ceilings and light rain linger around KCPR through 00Z, before
the rain ends and ceilings lift back to VFR. Gusty southerly
surface wind to start the period, especially at KRKS and KCPR,
gives way to gusty west to northwest wind Monday afternoon. The
strongest wind of 30-35 kt blows at KRKS is expected to start
and last through 00Z. There is a 30% chance for a discrepancy
with wind direction, due to the path of the aforementioned 700mb
low. Widespread mountain obscurations occur throughout the TAF
period.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM MST this afternoon for
WYZ012-014-024.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...CNJ/LaVoie