374
FXUS65 KCYS 191108
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
408 AM MST Wed Nov 19 2025

.KEY MESSAGES...

- Seasonable temperatures and mostly dry weather expected
  through Wednesday night. Mountain snow showers possible each
  day.

- Models continue to alternate on the strength and placement of
  a low later this week, but expecting at least some
  precipitation and snow with this system, mainly south of the
  North Platte River Valley.

- First real shot of cold air could arrive as early as next
  week, with high temperatures possibly in the 20s and 30s.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 120 AM MST Wed Nov 19 2025

Quiet night tonight across southeast Wyoming and western Nebraska
with cool temperatures and light winds. Temperatures are sitting in
the 30s as of 08Z with winds randing from 5 to 8mph. Clouds are
drifting across the region with lower clouds ongoing over Carbon
County and higher clouds elsewhere. Some shallow fog may develop
tonight along the North Platte River valley and potentially spread
in the Alliance and Chadron areas.

Fairly quiet weather is expected today and most of the day tomorrow
as upper-level flow remains fairly stagnant between upper-level
cutoff lows. Broad, weak ridging will be present today in the upper-
level as a trough over southern Canada slides slightly further
south, increasing upper-level flow over the region. With the upper-
level Canadian trough disturbing the atmosphere today, clouds are
expected, despite the broad ridging across much of the area. Breezy
conditions are possible during the morning hours as a 700mb
shortwave quickly traverses west to east across northern portions of
the CWA. Largely southwesterly flow will be present across the
region at 700mb with southerly to southwesterly flow expected
near the surface. As a result, upslope development is possible
along the Sierra Madre Range, with precipitation chances in the
20 to 25% range from now through about 21Z today. The Snowies
could see some of this upslope development, however, they will
remain mostly shadowed by the Sierra Madres under southwesterly
flow. The Sierra Madres could see 1 to 3 inches of snow this
morning before precipitation chances cut off this afternoon as
flow becomes less favorable for upslope development.
Temperatures today will be in the mid-40s to mid-60s across the
region, with the coolest temperatures west of the Laramie Range.

Quiet weather continues into the day Thursday as an upper-level
trough attempts to move into the region before getting absorbed into
the flow ahead of the next upper-level low moving into western
California overnight Thursday. With the messier upper-level flow on
Thursday, cloud cover will increase throughout the day becoming
mostly overcast overnight as a 700mb low attempts to develop over
the Panhandle of Oklahoma around 00Z Friday. This low is progged to
move slowly to the northeast between 00Z and 12Z Friday morning,
when the low will be over western Kansas. There is still some
uncertainty with this system as models are not in the best run-to-
run agreement on the track of the system. Most models keep this low
too far south to really give the CWA much chance for decent
precipitation. However, if precipitation occurs, it will begin in
the mountains late Thursday morning and remain confined there until
00Z Friday when that 700mb low really begins to develop. Between 00Z
and 12Z Friday, 700mb temperatures appear to be a touch too warm for
a pure snow event in the lower elevations, assuming the
precipitation makes it this far north. Therefore, a rain would be
the primary precipitation until about 06 to 09Z, when temperatures
have cooled enough to get a rain/snow mix east of the Laramie Range.
Given uncertainty with the track of the low, kept PoPs fairly low,
in the 40s to 60s, with the highest PoPs in the mountains where
confidence is highest in decent precipitation chances. This event
does not look to produce enough snow accumulation in the mountains
to warrant any kind of winter weather headline at this time. This
may change in future forecast updates as models come into better run-
to-run agreement on the track of the 700mb low.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 311 PM MST Tue Nov 18 2025

The long term will be semi-active as a system moves across the
region Thursday into Friday, but with the bulk of this expected
to our south only a glancing blow of precipitation is expected
with overall fairly light impacts. Following this, ridging and
a slight warming trend is expected through the weekend, with
another southerly tracking low possibly glancing us on Monday,
but moving into Tuesday deep troughing from the north should
bring a cold front just beyond the long term that will cause
temperatures to drop notably and further precipitation chances
as we begin to approach Thanksgiving.

At the start of the long term a cutoff low will skirt to our
south with low overall impacts expected for the region. While
we will see a glancing blow and some precipitation chances
primarily along the I-80 corridor, ensembles and deterministic
are beginning to agree that the track of this system will be too
far south to bring more noteworthy impacts to the CWA. Areas of
showers and high elevation snow Thursday into Friday are
expected, with some snow possibly mixing into rain overnight
into Friday morning for areas east of the Laramie Range, but
minimal accumulations are expected if any. What can be expected
is that areas that see precipitation will have lower highs on
Friday, with our western zones and areas along and south of I-80
stuck in the 40`s for the most part, while areas further north
should peak somewhere in the low to mid 50`s for the day. Over
the weekend the region will remain generally in between systems,
though some weak transient ridging should overspread and keep us
dry and mostly clear, with areas east of the Laramie Range
warming back up into the widespread 50`s. Into Monday we`ll see
another low to the south of the region and guidance wants to
track this system even further south, bringing almost nil
impacts to sensible weather concerns. But overnight Monday into
Tuesday a deep trough from a stout Canadian low will begin to
descend into the region, with a cold front knocking on the
doorstep of the CWA by the very end of the forecast period - a
sign of the cooler temperatures to come as we move into the
holiday timeframe. This system could include rain and snowfall,
so keep a lookout for updates on this as we get closer to this
timeframe.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 406 AM MST Wed Nov 19 2025

Low clouds and fog are beginning to develop across western
Nebraska, specifically KBFF and KAIA. Low clouds may drop
conditions to IFR or LIFR early this morning, with additional
visibility reductions expected. KRWL is starting to see some
lower clouds as well and brief MVFR to IFR conditions are
possible. Clouds and fog begin to clear around 15Z as winds
increase across the area.


&&

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

&&

$$

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