745
FXUS65 KCYS 161741
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1141 AM MDT Thu Oct 16 2025

.KEY MESSAGES...

- A storm system will move through the area today, first
  bringing showers and thunderstorms, followed by mountain snow
  and strong winds across the wind prone areas of southeast
  Wyoming.

- A High Wind Warning is in effect for the Elk Mountain and
  Arlington area along Interstate 80 for late this evening
  through most of Friday.

- A series of clipper systems will impact the region on Saturday
  and on Monday with another round of strong winds and some rain
  and snow mix possible down to 6000 feet.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 310 AM MDT Thu Oct 16 2025

Forecast for the remainder of the week looks on track as the
upper level low has moved northeast into northern Utah at this
hour, and is expected to lift into central Wyoming by this
afternoon. Multiple lines of strong thunderstorms, with a few
severe thunderstorms, moved across mainly southeast Wyoming late
yesterday evening with a few reports of hail and very heavy
rainfall. This activity has since lifted north into the Dakotas.
Another cluster of showers with embedded thunder is currently
moving north across Carbon and Albany counties at this hour, but
is much weaker compared to the convection last night. Areas of
fog have been observed east of the Laramie Range and expect this
to continue through sunrise until winds begins shifting into the
west. Otherwise, kept scattered to numerous showers in the
forecast with a few isolated thunderstorms. This activity is
expected to slowly translate eastward into the I-80 corridor
this morning with fog lifting across southeast Wyoming by 900 AM
as the warm front lifts north and the surface cold front moves
east across the region through the early afternoon hours.

Once the cold front progresses eastward into the plains, surface
to 700mb gradients are expected to increase late this afternoon
through tonight. Models continue to show increasing low level
subsidence along the Laramie Range and the Snowy Range tonight
with 700mb winds increasing over 50 knots through Friday
morning. With the Canadian on board and in-house wind guidance
showing increasing probabilities, decided to upgrade the High
Wind Watch to a Warning for the Arlington/Elk Mountain area
along I-80 for gusts of 60 to 65 MPH. Models are also showing
the surface gradient increasing several hours ahead of the 700mb
gradient, so nudged the timing a few hours earlier and started
it at 900 pm. Further east, the signal for high winds are not as
clear compared to Arlington, so kept the Watch going for
now...including portions of Interstate 25. To complicate
matters, another high wind event is possible for these same
areas Friday night ahead of the progressive clipper diving
southeast.

Otherwise, high temperatures today and Friday look to be near
average for most of the area with highs in the 60s, and slightly
below average west of the Laramie Range/I-25 corridor with
highs in the upper 40s to mid 50s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 406 PM MDT Wed Oct 15 2025

As the trough that brought about our short term weather departs,
a secondary clipper trough from our northwest will move across
the region late Friday into Saturday. While moisture may not be
as abundant as it currently is, a few showers and mountain snow
showers may be possible. This clipper is bringing in some
cooler air, and could even bring snow levels lower than expected
with a quick glancing hit of some lower elevation snow, but it
would be brief and not expected to accumulate of course.
Meanwhile the jet associated with this feature could once again
fuel another round of strong winds on Saturday, bringing high
wind gusts to our wind prone locations. Sunday a transient ridge
will help to clear us out and briefly warm us back into the
60`s to low 70`s, but a deep Pacific trough will bring another
round of rain and breezy winds Monday into Tuesday of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1136 AM MDT Thu Oct 16 2025

With our lowered ceilings and precipitation beginning to move
out, VFR conditions expected across the majority of sites today.
The one exception will be KRWL where another batch of rain is
moving towards the region and could impact through the afternoon
with some lowered CIGs or possible brief lowered VIS. Outside of
this, cloud decks will be lifting and clearing through
tomorrow morning. Winds will be gusty though, with speeds 20-40
knots through tomorrow morning and generally from a westerly
direction all sites.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from late tonight through Friday afternoon for
     WYZ106-107-116-117.
     High Wind Warning from 9 PM this evening to 3 PM MDT Friday
     for WYZ110.
NE...None.

&&

$$

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