234
FXUS65 KCYS 170017
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
517 PM MST Sun Nov 16 2025

.KEY MESSAGES...

- A Pacific storm system will move into the area later this
  weekend bringing snow...rain...and cooler temperatures by
  Monday.

- Gradual cooling trend expected next week with a chance of rain
  and/or snow Thursday and Friday.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 516 PM MST Sun Nov 16 2025

This evening a negatively tilted trough axis will quickly move into
the Rocky mountains and through the Intermountain West. As the
trough axis pushes East-Northeast, southern Carbon county will be
the first to receive precipitation. First it will come down as rain
then quickly switch over to snow as the temperatures quickly drop
below freezing. The GFS places a band of Frontogenesis over southern
Carbon county as the axis moves through region. Due to the enhanced
lift over that area the region, the QPF was increased from the
previous forecast. However, It was also reduced from the WPC QPF as
most of the Hi-res and Global guidance had between 17 and 20 inches
of snow for the Sierra Madre and Snowy Mountain for the event. While
the NBM and WPC grids had 24 to 28 inches for the snow accumulation.
The only 12z run that had total snow accumulations that high was the
HRW FV3. So snow accumulations were kept between 15 and 18 inches to
match the overall general consensus with the other high-res models.
However, since the higher snow accumulations are contained to the
higher peaks with limited road access and the impacts are lessened
and a winter weather advisory was kept instead of upgrading it to a
winter storm warning as the snow accumulations might suggest. For
the lower elevations (areas east of I-25) the precipitation is
expected to mostly stay as a rain and only a couple tenths or less
are to be expected. For the mountain adjacent areas near I-25 a
rain/snow mix wouldn`t be out of the question but any
accumulation wouldn`t amount to much in those areas.

A high wind warning was also issued between 5 am to 11pm Monday.
General consensus had the 700mb jet moving over our wind prone areas
between 55 to 62 knots with a westerly to Northwesterly wind.
Looking at the Omega fields, strong subsident flow was progged
during the time that the winds at 700mb strengthen. The rap also
showed the surface gradient tightening throughout the day Monday
gaining confidence in the high wind scenario for the Arlington area
as well as the foothills and Summit area between Laramie and
Cheyenne. Due to the winds switching to a northwesterly flow the
Bordeaux area was kept out of the warning since Bordeaux tends to
under perform and not experience high winds from the Northwest
direction. Also to increase confidence in our High Wind scenario our
in house algorithm also had a 60 percent probability to achieve high
winds over Arlington and the Summit indicating a strong signal for
those higher winds to mix down along I-80. The trough is expected to
move out of our area by Tuesday morning.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 516 PM MST Sun Nov 16 2025

The long term forecast looks rather unremarkable as the pattern
takes a shift towards more seasonable weather. Cooler temperatures
are expected behind Sunday night`s cold front, although temperatures
will still remain normal to slightly above average for this time of
year. Tuesday and Wednesday will feature warmer high
temperatures than Monday as weak ridging ushers in warmer air
aloft. Highs will be in the 40s and 50s, with some 60s
potentially sneaking into the Nebraska panhandle. For the most
part, subsidence under the ridge will keep precipitation at bay,
however, cannot rule out some light mountain snow from
increased mid-level moisture and orographic lift.

Heading into the end of the work week, a potential storm system
could impact the CWA. However, it appears models have trended this
system further south so that impacts to the CWA will be quite
minimal. Both the determininistic GFS and ECMWF as well as their
ensemble low clusters show the surface low developing pretty
far south in southeast Colorado/Oklahoma panhandle. Agreement
seems to be pretty good on the surface low development and
track, which will keep most of the precipitation out of the CWA.
As a result, lowered PoPs on Thursday and Friday below NBM
guidance. Temperatures will likely be colder both days as the
trough swings through the Rockies. However, the ECMWF advertises
colder temperatures than the GFS with colder air aloft.

Once this system moves out, temperatures look to warm back up over
the weekend, however models are in disagreement regarding whether or
not there will be precipitation.


&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 436 PM MST Sun Nov 16 2025

The next storm system will move into the area this evening. Rain
showers mixing with snow are expected to lead to MVFR to IFR
conditions at KLAR and KRWL beginning around 03 to 05z. After a
lull, rain and snow showers move back into KRWL for much of the
day Monday. Elsewhere, look for an initial round of showers to
move through overnight, which may linger through Tuesday around
KCDR and KAIA.

Look for strong gusty winds at all terminals behind the cold
front and through the day on Tuesday. Gusts in Wyoming will
range 30 to 40 knots, and will generally be 20 to 30 knots in
Nebraska.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 5 AM to 11 PM MST Monday for WYZ110-116-
     117.
     Winter Weather Advisory until 8 PM MST Monday for WYZ112-114.
NE...None.

&&

$$

SHORT TERM...MM
LONG TERM...SF
AVIATION...MN