326
FXUS65 KCYS 011918
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
118 PM MDT Sat Nov 1 2025

.KEY MESSAGES...

- High winds likely in the wind prone areas of southeast Wyoming
  Saturday night into Sunday. High Wind Warnings are in effect.

- Seasonably warm and dry conditions expected during the start
  to middle of week, but mountain precipitation and high winds
  return by the end of next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 110 PM MDT Sat Nov 1 2025

An upper-level ridge axis moving over the CWA this afternoon has
ushered in warmer air aloft, leading to a milder day across the
area. Temperatures currently sit in the 40s and 50s early this
afternoon, but should continue warming into the mid 50s to low 60s.
Heading into the evening and overnight hours, the ridge axis will
continue to move eastward past the CWA. This will turn winds aloft
more westerly, leading to a likely high wind event across the usual
southeast Wyoming wind prones.

With surface high pressure building over the Colorado Rockies and a
lee-side trough just east of the Laramie Range, a strong MSLP
gradient will develop along and west of the Laramie Range Saturday
night. The strengthening pressure gradients will cause 800 to 700 mb
winds to strengthen over the wind prone areas. Winds aloft will
max out at about 55 kts, peaking at around sunrise Sunday
morning. Subsidence is also very strong over the wind prones,
which will help get these winds down to the surface. Given this
set-up, high winds are likely Saturday night and into the day
Sunday. However, 700 mb CAG to CPR height gradients are not as
high as would be typical for a high wind event which does raise
some concerns. Despite this, in-house guidance gives Arlington,
Bordeaux, and the South Laramie Range a 60 percent chance at
seeing high winds. Because of this, went ahead and upgraded the
current High Wind Watches to Warnings. Winds in excess of 60 MPH
will be possible in these locations.

Given the high wind potential and warm air aloft on Sunday, well
above average high temperatures are expected. 700 mb
temperatures of +5C to +8C combined with strong downsloping
winds will lead to high temperatures in the 60s and 70s. Many
locations across the CWA will be within a few degrees of record
highs. Besides near record warmth, dry conditions are expected
throughout the day as much of the country enters a prolonged
upper-level zonal flow pattern.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 110 PM MDT Sat Nov 1 2025

Long term remains active as we see some warmer than average
temperatures to start the period, but by the end we`ll see the
return of high winds and mountain snow to the CWA. Monday begins
with an upper level ridge overhead but a weak shortwave will be
riding the upper periphery of this feature, bringing a dry cold
front across the CWA. While no precipitation is expected, this
feature should at least help in cooling off the eastern portion
of the CWA to near or just below average on daytime highs, while
areas west of the Laramie Range will run a little warmer into
the 60`s. Tuesday the eastern half of the CWA catches back up,
with widespread 60`s and 70`s likely as highs run 10-15 degrees
above average. Wednesday another shortwave will pass across and
should knock the region down back into the 50`s to 60`s, but
will still mostly remain several degrees above normal. Then
Thursday into Friday we`ll see activity really pick back up as
a more potent shortwave brings a steady cooling trend alongside
winds and mountain precipitation. For the precipitation, much
like the previous discussion models have been keeping us in the
drier portion of the trough with the bulk of the energy to our
north. That being said, upslope enhancement should produce
multiple rounds of generally light precipitation for our higher
terrain, mostly in the western and northern portions of the CWA,
with snow for the mountains and rain/snow mix for the adjacent
plains and valleys. Meanwhile the 700mb winds continue to look
supportive for a multi-day high wind event with in house
guidance in agreement, so for this run have nudged the winds
closer to the NBM 90th percentile to bring our region wide winds
higher and closer to high wind criteria. We will likely be
looking at high wind warnings beginning early Thursday and
continuing into the evening Friday based on current guidance and
if models continue to remain in agreement.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1140 AM MDT Sat Nov 1 2025

VFR conditions expected over the next 24 hours. High clouds
should begin breaking up this afternoon, but expect them to
linger until this evening. Winds will be mostly breezy today and
again tomorrow morning into the afternoon with gusts generally
in the 20-35 knot range. A strong jet overhead will bring
enhanced low level wind shear to all sites except for KRWL, with
speeds around 40 knots or so in difference at around 2K feet.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 2 AM to 2 PM MDT Sunday for WYZ106-116-
     117.
     High Wind Warning from 9 PM this evening to 2 PM MDT Sunday
     for WYZ110.
NE...None.

&&

$$

SHORT TERM...SF
LONG TERM...CG
AVIATION...CG