022
FXUS65 KCYS 140505
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1005 PM MST Thu Nov 13 2025

.KEY MESSAGES...

- A High Wind Warning has been issued for the Arlington/Elk
  Mountain and Bordeaux wind prone regions for Friday morning
  through Saturday morning.

- A Red Flag Warning has been issued for the Nebraska Panhandle
  for Friday morning and afternoon for low RH and gusty winds.

- A trough will move into the area later this weekend with
  chances for precipitation and cooler temperatures.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 329 PM MST Thu Nov 13 2025

Observed conditions have been running a little warmer and a
little drier than forecast today. Adjustments of around 3% to
temperatures and reductions in dewpoints by around 10% seem to
be the sweet spot to get our forecast closer to ongoing
observations. Because this was extended through Friday`s
forecast, this did bring critical fire weather concerns to the
Nebraska Panhandle. RH values are expected to bottom out in the
mid to low teens, and with winds gusting between 20-35 mph, a
Red Flag Warning was issued in collaboration with our
neighboring offices. On the note of winds, models continue to be
a little more aggressive on the 700mb jet with an extended
period of 50-55 knot winds from early Friday morning through
Saturday morning, and looking at the GFS omega fields, downward
omega values. In house guidance is also back on the aggressive
side and in agreement that these enhanced winds are expected for
several hours. While a brief lull may occur Friday afternoon, a
second round of stronger gusts is once again expected Friday
evening into Saturday morning. Because of this, the existing
high wind watches were upgraded to warnings and extended through
12Z Saturday.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 329 PM MST Thu Nov 13 2025

The next storms system will pass well to our north on Saturday, but
recent model guidance has trended further and further north. As a
result, this has begun to look more like a wind shift as little to
no precipitation is expected, and the temperature drop will likely
only be a few degrees. Look for highs in the upper 50s to 60s on
Saturday and Sunday, which, while likely no longer challenging
record highs, will remain about 10 to 15F above average for this
time of year. Saturday will remain breezy across the area with the
threat for high winds decreasing through the day in the wind prone
areas, while winds will come down for Sunday as the next system
approaches from the south.

The closed low that gets stranded near the California coast over the
next day or two will finally make its way east across the Rockies on
Sunday into Monday. The combination of unseasonably warm
temperatures ahead of this system and a nearly saturated atmospheric
column will lead to plentiful moisture. NAEFS mean precipitable
water values exceed the 99th percentile of climatology over most of
southeast Wyoming Sunday night into Monday morning. Thus, moisture
does not look like it will be an issue with this system. However,
the lifting mechanism is messy and disorganized which is the main
uncertainty regarding precipitation amounts. While the main low
pressure system will take a favorable track for widespread
precipitation across northeast Colorado, there will be a secondary
low both at the surface and in the middle atmosphere located over
central Wyoming which will interfere with the wind field and place a
deformation zone over the area. Westerly flow before and after the
deformation zone passes over will favor orographic lift along and
west of the Laramie range, putting the highest confidence in
precipitation over that area. East of the Laramie range, we will
have some light easterly flow present, but it looks rather shallow.
The primary low will eventually take over, leading to the
development of some modest overrunning aloft, but models differ in
how quickly this will happen. The faster this happens, the more
precipitation can be expected over the High Plains (and also the
lower the snow levels will drop). Speaking of snow levels, they will
begin this event very high for the time of year as the closed low
aloft runs into a very mild airmass. Expect this to drop through
Monday as limited cold air is wrapped in, but precipitation type
will be a forecast challenge throughout the event. Most areas
outside of the mountains can expect to see rain showers to start,
with some snow likely mixing in as the storm passes. With marginal
temperatures, accumulating snow is unlikely below about 7500 ft in
elevation (about 20% chance for 0.1" or more for these areas).
Wetting rainfall probabilities are a little higher, around 50 to 80%
for 0.1" or more of liquid precipitation. Of course, the higher
elevation mountains will be all or mostly snow, so there is decent
confidence in advisory criteria (6 to 12") of snow falling in the
Sierra Madre and Snowy range mountains. Accumulating snow is also
possible over the I-80 summit (20% chance for 1" at this time), but
confidence is lower there.

Regardless of the precipitation outcome, this system will knock down
temperatures and likely they will stay down for a while after this.
Look for near average highs on Monday and Tuesday (mid 40s to mid
50s). Attention will then shift to the next storm system, which will
be another disorganized closed low taking nearly the same track
across the southwestern US during the middle of next week. This
system will not be running into as warm of an airmass, so expect
lower snow levels and colder temperatures Wednesday into Thursday.
Any accumulating snow details remain highly uncertain. This is the
favored solution amongst the ensembles at this time, but a cluster
of about 30% of members suppress this system well to the south and
keep temperatures near average through the middle of the week while
delaying precipitation until next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1004 PM MST Thu Nov 13 2025

VFR conditions remain throughout the TAF period. Some mid-level
clouds will work their way through the forecast area around
15,000ft. Biggest threat to aviation will be the LLWS between
1,000 to 2,000ft from the west at 40kts. This jet looks to set
up around 08z and continue through Friday afternoon before
weakening.


&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 5 AM MST Saturday for WYZ106-110.
NE...Red Flag Warning from 9 AM to 5 PM MST Friday for NEZ434>437.

&&

$$

SHORT TERM...CG
LONG TERM...MN
AVIATION...MM