096
FXUS65 KCYS 211740
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1040 AM MST Fri Nov 21 2025

.KEY MESSAGES...

- Light rain showers will transition to a rain/snow mix around
  sunrise. Accumulations of less than half an inch expected east
  of the Laramie Range, with 1-2in possible in the higher
  elevations.

- Second system with another shot of rain and possible snow hits
  our southeastern zones early in the week with a deep Canadian
  low and trough bringing notably colder temperatures just
  before and through the holiday timeframe next week.

- Cold temperatures look to return for the upcoming week.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 100 AM MST Fri Nov 21 2025

Overcast skies ongoing across the entire CWA overnight as isolated
to scattered, light rain showers drift across the I-80 Corridor and
locations just north of the Interstate. Low stratus and fog has moved
into much of western Nebraska, with calm winds. Temperatures are in
the 30s to 40s for much of the region, except Rawlins which is
sitting at 29F as of 08Z. Overcast skies and light showers will
continue through the overnight hours into the early morning.

Overall, models have come into better agreement with the system
currently impacting the region. Most models suggests much less snow
accumulation than runs yesterday, with most agreeing on zero to a
trace of snow east of the Laramie Range and 1 to 2 inches in the
higher elevations. Light rain showers continue across the I-80
Corridor as 700mb remain slightly too warm to get snowfall as of 08Z
this morning. Closer to day break, it is possible that 700mb
temperatures will drop just enough to get a few flakes mixed into
any rainfall ongoing around 12Z this morning. Models soundings are
in agreement on a saturated atmosphere with slightly too warm
temperatures. With the significant cloud cover over the region, it
is possible that temperatures will not drop enough to allow for
snowflakes to mix into the precipitation. If they do cool off
enough, the best period of snowflakes east of the Laramie Range will
be from about 12 to 16Z. However, by this time, the 700mb and
surface lows will be well off to the east. The GFS, NAM, and RAP all
suggest easterly, upslope flow continuing through 15Z, so the best
chance for snow will be early this morning, shortly after sunrise.
Precipitation chances with taper off through the morning hours, with
dry conditions returning by 00Z this evening. Skies will remain
mostly cloudy along the I-80 Corridor through the day and late into
the evening before clearing skies return overnight tonight.

Messy upper-level flow is expected to develop by Saturday morning,
as the next upper-level low moves towards the Four Corners region.
Cloud cover from this system will start moving in late Saturday
night into early Sunday morning. Temperatures Saturday will recover
into the 40s and 50s everywhere. Winds may briefly increase early
Saturday morning across Carbon County and the typical wind-prone
regions of southeast Wyoming as 700mb height gradients strengthen as
a result of shortwave moving across southern Canada. The gradient
increase is not expected to be significant, but should be enough to
get some breezy winds kicking up in the wind-prones. High winds are
not expected at this time.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 248 PM MST Thu Nov 20 2025

Long term is quite active as we see a second low skirt by to our
south with the strongest impacts remaining outside of our CWA
again but another shot of precipitation is likely for our
southern zones. Following this, a deep upper level trough will
move in from the Pacific and a cutoff low will form along the
border of the US/Canada, sweeping a cold front across the CWA by
Tuesday morning that will cause our temperatures to plummet, as
well as produce further precipitation that will be more
widespread.

The long term begins on Saturday in between southern tracking
low pressure systems, generally with our region out of direct
influence of any one feature though weak transient ridging will
pass across into the later part of the weekend. Benign
conditions and still warmer than average temperatures will
linger through Sunday morning, but by the afternoon the next low
to track to our south passes across with once again the bulk of
any major influence just outside of our region. Still, another
glancing blow of precipitation is expected for our southeastern
zones, with light accumulations of rain and some mixing into
snow expected, primarily along and just east of the Laramie
range. But as we move into Monday, we`ll see a noteworthy
pattern change as a deep trough moves in from the Pacific and a
cutoff low forms along the US/Canadian border. This system will
be accompanied by a stout cold airmass, and while we won`t be
reaching record cold by any means, it`ll be our first real
powerful shot of a colder winter style airmass. Highs are
expected to drop into the widespread 30`s to low 40`s by
Tuesday behind the front, alongside lows in the teens to mid
20`s. These temperatures should hold through the Thanksgiving
holiday under northwesterly flow on the backside of this trough.
Meanwhile, we should see multiple bouts of precipitation during
this timeframe, with the bulk of it occurring in the higher
terrain of our western zones but sometimes spilling into the
lower terrain and high plains to the east. Overall the moisture
available will be minimal, but we should still see several
inches of snow accumulation potential, highest in the mountains
of course but occasionally down into the lower elevations and
with temperatures as cold as they are expected, remaining snow
as it occurs down here as well. Winter-like conditions are here
to greet us as we approach the holiday!

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1038 AM MST Fri Nov 21 2025

Aviation conditions will gradually improve over the forecast
period. Lingering MVFR to IFR issues at KCYS and in the southern
NE panhandle should resolve by mid-afternoon with generally
light winds overnight into Saturday morning.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...AM
LONG TERM...CG
AVIATION...MN