538
FXUS65 KCYS 152214
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
314 PM MST Sat Nov 15 2025

.KEY MESSAGES...

- A Pacific storm system will move into the area later this
  weekend with chances for precipitation and cooler
  temperatures by Monday.

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

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 310 PM MST Sat Nov 15 2025

A mild afternoon continues across the CWA despite cloud cover from
mountain wave activity. Temperatures east of the Laramie Range hover
in the 60s, while 50s are being observed for areas out west.
Temperatures likely will not get much warmer than this if clouds
persist. However, breezy downsloping winds will sustain these
temperatures through the afternoon. As the upper-level ridge
axis begins to move into the CWA this evening, winds will ease,
leading to a calm overnight.

With the upper-level ridge axis over the CWA on Sunday, another mild
day is expected across the area. Mostly sunny skies from subsidence
under the ridge as well as warm air advection from southwest flow
aloft will fuel above average temperatures. High temperatures will
once again be in the 50s and 60s, which is about 10 to 20 degrees
above average, depending on the location. The ridge will keep
conditions mostly dry throughout the day, however, an approaching
potent trough could bring a few showers to Carbon County later in
the afternoon.

Heading into Sunday night, precipitation will become more prevalent
as the trough moves into Wyoming. Pacific moisture associated with
the trough will likely lead to fairly widespread precipitation west
of the Laramie Range. The mountains, and in particular the Sierra
Madre Range, could pick up Advisory level snowfall amounts by the
end of this progressive event as sustained orographic lift will
support decent snowfall rates. The Snowy Range will likely feel some
shadowing during this event and will likely see totals just at or
below Advisory criteria. Since precipitation is expected overnight,
snow and/or a mix could make it into some of the adjacent lower
elevations. However, accumulations are not likely in places like
Rawlins and Laramie as ground temperatures could be too warm from
several mild days. Temperatures aloft will also be hovering around
0C, so snow levels could be too high to get any decent
accumulations. As the cold front crosses the Laramie Range, models
show downsloping winds drying out this system, leaving little to no
precipitation for areas along and east of Interstate 25. Winds will
also pick up behind this cold front, leading to potential high winds
in the usual southeast Wyoming wind prones Monday morning.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 310 PM MST Sat Nov 15 2025

Mid level water vapor shows a very active Pacific
Ocean confirming what the global models depict for the weather over
the next week. an upper level shortwave will be pushing through the
Intermountain West Sunday night into Monday. This negatively tilted
shortwave develops some leeward cyclogenesis off the Rockies to give
us a some potential widespread precipitation chances across
Southeast Wyoming and the Panhandle of Nebraska. This newly created
system is expected to slowly drift off to the East-Northeast will
advecting in a decent amount of moisture from the Pacific with it.
Due to the enhanced synoptic lift generated from the Denver cyclone
and adequate moisture being advected in, Snow total estimates could
prompt a winter weather advisory for the Sierra Madre and Snowy
mountains. A brief ridge sets up Tuesday night into Wednesday,
however another system pushes into the Western coast Wednesday
night. Cluster Analysis shows some uncertainty with the location and
strength of the next system. Some clusters show a potential for the
system to track to the northeast from the California coast allowing
for the system to become negatively tilted as it tracks through the
Intermountain West to give us daily precipitation chances through
the weekend. The other clusters depict a more eastern track from the
California coast. This track amplifies a ridge over the
Intermountain West as the system would then traverse the southern
portion of the United States. If this ridge sets up it would
decrease the precipitation chances in the back half of the week
extending through the weekend.

The global ensembles have also reached a consensus of the gradual
downward trend in the daily high temperatures. Colder air spills
down from the Canadian Providences following the low pressure
systems moving through the upcoming week. 700mb temperatures are
expected to hover around -4c for this upcoming week. This will
gradually drop temperatures from the 60`s at the start of the week
into the 40`s by the weekend. Overnight temperatures also look to
ride the downward trend with temperatures reaching into the 20`s by
next weekend. Ensembles do show the downward temperature trend
continuing to the end of the month. By the end of the month high
temperatures could be in 20`s and 30`s with overnight temperatures
in the teens if this trend continues.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1007 AM MST Sat Nov 15 2025

VFR conditions will continue over the next 24 hours. Gusty
winds this morning will continue into this afternoon for all
southeast Wyoming terminals. Generally light winds for western
Nebraska, but can`t rule out a few gusts around 20 knots from
the west or northwest.

&&

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

&&

$$

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