546
FXUS65 KCYS 250535
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1035 PM MST Mon Nov 24 2025

.KEY MESSAGES...

- A High Wind Warning remains in effect for the typical wind-
  prone regions of southeast Wyoming through early Tuesday
  morning.

- A High Wind Watch has been upgraded to a High Wind Warning
  for the northern counties across the Nebraska Panhandle from
  8PM tonight through 2PM tomorrow.

- A strong cold front will bring a slight chance of light snow
  this evening into tonight for our northern counties of our
  CWA in Wyoming followed by wind chills in the teens and 20s on
  Tuesday.

- The probability of an arctic cold front is increasing for
  next weekend which will usher in very cold temperatures and
  accumulating snowfall.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 321 PM MST Mon Nov 24 2025

Strong winds will spread east across the CWA along with increased
chances of precipitation, albeit very slim, for our northern
counties through the afternoon hours. All this is due to an upper-
level trough that dives southeast towards our CWA today into tonight
and off to our east by tomorrow afternoon. A shortwave aloft along
with a vorticity maxima will clip our northern counties, Converse
and Niobrara, increasing the threat of precipitation.
Initially, any precipitation that falls should be rain and then
transition to mainly snow this evening as a surface cold front
pushes through, dropping temperatures. If your wondering if this
will produce substantial snowfall, in short, no. Any snow that
falls, accumulations will be meager, primarily less than an inch
for the aforementioned counties above. Winds across our known
wind prone areas along I-25 and I-80 will be the main weather
threat going into Tuesday. Why, lets take a look at the mid-
levels where a stout 700mb jet sets up across the Laramie Range
with winds up to 65 knots. These stronger winds will mix down
towards the surface due to negative Omega fields (GFS),
resulting in surface winds that may gust up to 70 mph. As such,
there are High Winds Warnings in place for the typical wind-
prone areas across southeast Wyoming.

As this trough continues its southeasterly track, a 700mb low
strengthens over South Dakota tonight into Tuesday morning.
This coupled with a 850mb jet and negative Omega fields (GFS)
will help mix down the winds at 850mb to the surface across the
Nebraska Panhandle. Expect winds to gust up to 60 mph for Sioux,
Dawes, and Box Butte counties. Hence, the upgrade from the High
Wind Watch that was issued earlier today to a warning through
21Z Tuesday. As this upper-level low ejects off to our east,
winds will shift to the northwest and usher in widespread
colder temperatures, of which will be the coldest so far this
season. Expect temperatures to plummet tonight with lows
bottoming out in the teens west of I-25 and 20s east of the
corridor. Temperatures will remain cooler for Tuesday as highs
will struggle to reach the 30s across the CWA with lows taking
another nose dive for the overnight hours, expect a cold
Wednesday morning as you go outside with temps in the teens for
many locations.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 321 PM MST Mon Nov 24 2025

Long term will be active thanks to a quick moving shortwave
trough during the mid-week timeframe that will bring some gusty
winds and light mountain precipitation, but the real story is
this weekend when a deep trough in the Western US will
absolutely plummet temperatures with widespread highs below
freezing and overnight lows into the single digits to end
November and bring in the start of winter in December.

To start the long term, we`ll be under northwesterly flow aloft
from a ridge over the Western US that will shift over the region
through Friday. Wednesday should start off a bit blustery due to
a weak shortwave aloft passing along the periphery of the CWA,
and we may even see near to high winds for the Arlington wind
prone region, but outside of this we should stay just outside of
high wind criteria for the majority of our area. A few mountain
or high terrain snow showers may also occur thanks to this
system, but with flow upslope over the western side of the
region and moisture on the low side, this should only produce a
few light amounts early on before moving out of the region.
Moving into the remainder of the week, benign conditions are
expected under ridging through early Friday.

But moving into the weekend, we`ll see a noteworthy pattern
change as models indicate a shortwave should move across on
Friday, followed by a very deep trough overtaking the Western US
into Saturday with a cold airmass accompanying this system as
we move into the last couple of days of the month. There`s still
some variation on the strength and exact placement of this
system with ensemble clusters showing a few variations of this
feature, but all in agreement on the trough taking over the
West, leading to high confidence in the pattern change but
low to moderate confidence in the exact outcome for our area.
What we expect currently is multiple waves of precipitation with
temperatures cold enough to produce widespread snow beginning
as early as Friday morning and continuing through the start of
next week before moisture finally exits. With the uncertainty
currently expected, getting amounts pinpointed this far out is
difficult at best, but current estimates would place several
inches for all of our zones by Monday morning. Meanwhile
widespread temperatures at or below freezing will begin Friday
afternoon/evening and last through early next week as well, with
the coldest day expected on Sunday as widespread highs in the
20`s with a few 30`s possible and lows into Monday morning
almost widespread single digits. As mentioned though there
remains a bit of uncertainty, and the NBM is showing a spread in
Cheyenne for example of around 17 degrees for our afternoon
high Sunday, indicating we could be as "warm" as 29 degrees or
as cold as 12 for the day! But no matter where we land, this
will be the coldest we`ve seen for the year, so everyone should
be prepared for winter to make itself known as we move into the
post-holiday timeframe.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1035 PM MST Mon Nov 24 2025

A Pacific upper level trough and associated cold front will slide
southeast across the region. Very little to no precipitation is
expected, but very windy conditions are expected tonight and into
Tuesday morning for all terminals.

HAZARDS/WEATHER TRENDS: VFR will prevail tonight for all terminals.
Windy conditions will be the main impact to Aviation through 21z
Tuesday. Expect gusts up to 40 knots to possibly 45 knots for all
terminals. Winds will shift into the northwesterly after 06z and by
09z. Winds are not expected to subside until late Tuesday into
Tuesday evening.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...High Wind Warning until midnight MST tonight for WYZ106.
     High Wind Warning until 5 AM MST Tuesday for WYZ110-116-117.

NE...High Wind Warning from 8 PM this evening to 2 PM MST Tuesday
     for NEZ002-003-095-096.

&&

$$

SHORT TERM...RZ
LONG TERM...CG
AVIATION...TJT