200
FXUS65 KRIW 171956
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1256 PM MST Mon Nov 17 2025

.KEY MESSAGES...

- Weather system exits the area today, with rain and mountain
  snow chances decreasing through the afternoon.

- Temperatures are much cooler and near normal today, but will
  be slightly warmer Tuesday and Wednesday.

- The weather pattern is trending toward cool and mostly dry for
  the rest of this week into this weekend as weather systems
  miss Wyoming to the south.

- With the weather systems sliding south temperatures will
  remain cool, but close to normal for mid-November.

&&

.UPDATE...
Issued at 1254 PM MST Mon Nov 17 2025

The rain and mountain snow is trying to hang on this afternoon, but
ultimately will taper off by this evening as the upper-low slides
east. As expected temperatures are cool, but close to normal for
this time of year. Wind will remain breezy through the afternoon
across southern Wyoming, with gusts of 25 to 35 mph. It should be a
bit warmer Tuesday and Wednesday thanks to high pressure, but there
will be enough cloud cover to prevent highs from reaching values of
the past week. This means highs will be in the 50s east of the
Continental Divide and 40s west of the Continental Divide. There
remains much uncertainty in regards to the weather pattern and
system late this week into this weekend. There is a better
chance (70%) for minimal impacts than moderate to high impacts
(30%).

&&

.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 /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1117 AM MST Mon Nov 17 2025

IFR to MVFR conditions are noted at several terminals late this
morning as a midlevel low moves east into the Great Plains. Given
that we are now on the backside of this system, we do expect some
improvement through the afternoon. Still, low ceilings will persist
through most of the overnight hours before lifting by late Tuesday
morning. There is some indication that there may be some fog at
KJAC, KBPI, and KPNA, but confidence is too low to add to TAFs for
now. Gusty winds will be seen this afternoon at KCPR and KRKS,
decreasing after sunset.

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

&&

$$

UPDATE...Rowe
DISCUSSION...Dziewaltowski
AVIATION...Myers