078
FXUS65 KCYS 020600
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1055 PM MST Sun Nov 1 2026

.KEY MESSAGES...

- A complex but disorganized storm system will move into the
  area Sunday, bringing multiple rounds of rain and snow showers
  through Tuesday morning.

- Winter Weather Advisories are in place for the mountains as
  well as the Arlington area and South Laramie Range.
  Accumulating heavy, wet snow is possible in these areas.

- Widespread windy conditions are anticipated Monday and Monday
  night.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 324 PM MST Sun Nov 1 2026

Currently looking at a dreary day across most of the forecast area.
A blanket of cloud cover sits over the CWA with patchy fog dotting
southeast Wyoming and the Nebraska panhandle. Radar does show some
light echoes as well, however its hard to confirm whether or not any
precipitation is currently making it to the ground. Temperatures are
a bit cooler than anticipated, mainly due to the thick cloud cover
and lingering fog. But, warm air advection still persists with moist
southerly flow keeping 700 mb temperatures on the mild side.
Precipitation coverage will increase this evening and overnight, but
will likely still be on the spotty side until the system becomes
more organized. The cold front will arrive Sunday night,
gradually ushering in cooler air. Simultaneously, leeside
cyclogenesis will be occurring in northeast Colorado, forming a
surface low. Cluster analysis from both the GEFS and ECMWF
ensemble are still in good agreement regarding surface low
placement and track into the day Monday. A majority of the
precipitation that falls overnight will be rain as cooler air
slowly fills in behind the front. The exception to this, of
course, will be the mountains. Winter Weather Advisories are in
place for the Snowy and Sierra Madre Range starting tonight.
Snow will begin later this evening and continue through the day
Monday. At the end of the event, locations above 9000 feet will
likely pick up between 6 and 12 inches.

A colder day is expected Monday behind the front with temperatures
in the 30s and 40s for southeast Wyoming and low 50s for the
Nebraska panhandle. As a result, snow could begin to mix with rain
as snow levels drop to about 5500 feet. The mix and potential full
change-over to snow could happen as early as Monday morning for
locations along and west of the Laramie Range. PWATs are at
climatological max per NAEFS and more closely resemble that of a
summer monsoon event! As a result, expect fairly good precipitation
rates, especially with Hi-Res guidance showing steady and widespread
precipitation once the CWA enters the wrap around moisture regime of
the surface low ejecting into Nebraska. Higher precipitation rates
could lead to a quicker change over to snow, and thus the potential
for higher snowfall accumulations. The mountains and higher
elevations are still the areas with the highest confidence in seeing
accumulations. Winter Weather Advisories are also in effect for the
North Laramie Range, whose northern slopes could see between 6 and
12 inches from upslope flow, and the Arlington area and South
Laramie Range. These higher elevation spots along Interstate 80
could pick up roughly 2 to 4 inches of heavy wet snow given the
temperatures and PWATs. This could lead to difficult travel at
times. Areas outside of the aforementioned locations west of the
Laramie Range could also see accumulating snow ranging anywhere
from a trace to 2 inches. Snow amounts are a bit more uncertain
east of the Laramie Range as the transition may or may not
happen later in the day. Hi-Res guidance shows steady
precipitation in this area during the afternoon and into the
evening hours. Places like Cheyenne and Douglas could see some
minor accumulations, but even this is uncertain. Ensemble
guidance from both the GFS and ECMWF show very few members with
even light accumulations for these cities. The other area to
watch will be the Pine Ridge. The HRRR is really latching onto
the upslope flow and nails the Pine Ridge between Lusk and
Chadron with fairly high accumulations. This is even more
uncertain, but lingering precipitation Monday night combined
with the north winds could lead to quickly accumulating snow.

The other issue Monday will be the strong winds. As the surface low
ejects into Nebraska, a strong MSLP gradient will set up on the
eastern plains. Hi-Res guidance like the HRRR suggests marginally
high winds east of the Laramie with gusts up to 60 MPH. However,
given a lack of any decent subsidence, its hard to rationalize that
widespread 60 MPH winds will materialize Monday afternoon into
Monday evening. Even NBM probabilities of wind gusts >48 kts
are on the low side across the plains. For now, held off on any
high wind headlines to allow for a few model cycles to see if
there is greater confidence in wind gusts. Regardless, it will
be windy on Monday, with frequent gusts of 50 to 55 MPH. These
blustery conditions will continue into Tuesday morning, before
weakening during the afternoon hours.

The weather on Tuesday looks quieter as the surface low pushes
further off to the northeast. Some lingering precipitation and wind
will still be present in the Nebraska panhandle during the morning
hours, but will taper off by the afternoon. Decreasing clouds are
expected throughout the day with mostly sunny skies anticipated by
the afternoon. Upper-level ridging will quickly move in behind
the storm system, leading to warmer temperatures as 700 mb
temperatures rise back into the single digits. Highs in the 40s
and 50s are likely, however, could be cooler based on amount of
snow cover.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 342 PM MST Sun Nov 1 2026

As we start off the long term period, lets take a quick look at the
synoptic setup, we have a deep trough draped south across the
Central Plains, just to our east, while ridging builds in from the
west. This ridge will keep us in a dry northerly to northeasterly
flow regime across our CWA with plentiful sunshine making a
triumphant return. As we progress into Wednesday, weak ridging is in
place overhead while model consensus has another cut-off low diving
southeast from Idaho. This feature will bring an increase chance of
precipitation primarily across the Sierra Madre and Snowy Ranges.
Where at the higher elevations could get and inch or two of fresh
snow. Otherwise, for the remainder of the CWA, this system will not
have any impacts elsewhere as it continues to dive southeast across
the Four Corners region through Wednesday. Quickly behind it,
ridging nudges back in late Wednesday into Thursday. By the tail end
of the week into next weekend, there are some differences in model
solutions with the placement and amplitude of synoptic features.
With the ECMWF having a deep trough just to our east while the GFS
has the trough slightly further east over the Great Lakes. However,
most model solutions have a ridge in place over our region with dry
northwesterly flow. With all that being said, stay tuned to the
forecast for future updates.

Now, switching gears and taking a closer look at temperatures for
the long term period, expect highs to climb into the mid to upper
40s, possibly a few location topping out in the lower 50s, west of I-
25. While temperatures will soar into the lower to mid 50s east of I-
25 for the remainder of the work week into the weekend. In general,
expect lows to dip into the lower to mid 30s across the CWA,
possibly slightly colder west of the I-25 corridor.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1055 PM MST Sun Nov 1 2026

Potent Pacific storm system and associated cold front will move into
the Front Range late tonight and push through the area Monday
morning. Periods of fog and rain showers will transition to steady
rainfall (high elevation snow) and very windy conditions across the
eastern plains after 12z Monday.

HAZARDS/WEATHER TRENDS: Complicated Aviation forecast setting up for
the next 18 to 24 hours with generally low confidence for most
terminals. Periods of rain showers, locally heavy at times, will
continue through 09z. In between this shower activity, light and
variable winds will result in periods of fog at times. Once the cold
front moves southeast across the area between 08z (KRWL & KCDR) and
12z (KCYS, KSNY) winds will quickly shift into the northwest and
increase between 20 to 35 knots with higher gusts, mainly over the
high plains terminals. Can`t rule out a few hours of VFR conditions
as this front moves through the area, but MVFR to IFR CIGS will
generally follow, including KLAR and KRWL by 15z where some light
snow is possible. Precipitation coverage and impacts are uncertain
for Monday as most models have backed off on intensity and areal
coverage. Pretty confident that KAIA, KSNY, and KCDR will see IFR
conditions returning around 00z Tuesday with widespread rainfall.
Limited confidence for this in KBFF and KCYS with light rain and
MVFR conditions looking more probable at this time.



&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory from 5 AM to 11 PM MST Monday for
     WYZ103.
     Winter Weather Advisory from 5 AM to 5 PM MST Monday for
     WYZ110.
     Winter Weather Advisory from 11 PM this evening to 11 PM MST
     Monday for WYZ112-114.
     Winter Weather Advisory from 11 AM to 11 PM MST Monday for
     WYZ116.
NE...None.

&&

$$

SHORT TERM...SF
LONG TERM...RZ
AVIATION...TJT