416
FXUS65 KCYS 100000
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
600 PM MDT Thu Oct 9 2025

.KEY MESSAGES...

- Precipitation chances return for Friday into the weekend,
  mainly west of I-25.

- The return of our annual strong winds is expected this weekend
  with gusty conditions possible for our wind prone regions.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 330 PM MDT Thu Oct 9 2025

Currently a pleasant afternoon across most of the area with mild
temperatures and partly to mostly sunny skies. Radar shows a few
light showers with some lightning strikes between Arlington and Pine
Bluffs, however these do not seem to be causing any sort of
disruptions or impacts. Per Hi-Res guidance, these showers will
continue through the evening hours as a weak disturbance moves
aloft. Overnight, clouds will begin to increase ahead of the next
storm system, resulting in slightly warmer overnight lows.

Heading into Friday, the upper-level pattern looks like that of a
monsoon. With a 500 mb high over Texas and a trough off of the west
coast, moist southwest flow will dominate. This southwest flow will
bring a plume of moisture into the western half of the CWA. This
moisture will begin to move in Friday morning, causing showers to
develop over Carbon County. As the day progresses, these showers
will spread eastward into Albany County and the Laramie Range.
Despite rather impressive PWATs for this time of year, rainfall
totals will be unremarkable as little forcing is present. A
brief lull in shower activity will be possible during the
evening hours before a stronger surge of moisture arrives Friday
night. An upper-level disturbance moving across the CWA Friday
night will provide weak lift need for stratiform precipitation
to develop. Rain can be expected late Friday night across Carbon
and Albany Counties. Rain will eventually move into areas east
of the Laramie Range by Saturday morning.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 330 MDT Thu Oct 9 2025

The long term will be an active period as rain and strong winds
are expected this weekend, followed by more chances for
precipitation next week alongside cool, fall-like temperatures.
Saturday the ridge will be shifting eastwards as a Pacific
trough moves into the region. With plentiful moisture continuing
to stream into the region and PWAT values 200-250% of normal,
even approaching 300% in locations, any precipitation that can
get going will have the potential to produce locally heavy
rainfall, and will need to be monitored accordingly. Thankfully
instability will be extremely meager, lucky to even reach 200
J/kg, so producing heavy showers or even a storm will likely be
orographically driven. This is reflected in the forecast, with
the bulk of any PoPs across our high terrain this weekend. Highs
Saturday will remain in the 60`s to mid to upper 70`s thanks to
the warm southwesterly flow from the influence of the ridge, but
that changes moving into Sunday with the trough moving across.
Highs west of the Laramie Range plummet, only reaching the 40`s
to 50`s. Meanwhile the trough brings a jet that will move
overhead and bring our first chance at seasonal high winds
Saturday night through Sunday. At 700mb, speeds up to 60-70 kts
are noted, which is conducive for high wind warnings, and our in
house guidance agrees for the potential to briefly hit the
criteria needed (58+ mph). The trough will sweep the moisture
out of our region however, so look for precipitation chances to
decline through the day Sunday.

Moving into next week, the rest of the forecast period should be
dominated by ridging and southwesterly flow, funneling moisture
back into our area that will once again be limited by a lack of
instability, keeping mountain precipitation the most likely
outcome. Temperatures will steadily but slowly warm, with highs
Monday in the 50`s, and then by Wednesday reaching back into
the 60`s to low 70`s. A steady modest jet overhead should keep
conditions breezy at times, but not nearly as gusty as Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 600 PM MDT Thu Oct 9 2025

Southwest flow aloft will continue tonight and Friday with intervals
of low to midlevel cloudiness. A few light rain showers are expected
early this evening with a higher coverage of showers and embedded
thunder after 17z Friday for the southeast Wyoming terminals.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail tonight. There
is a minimal to slight chance (5% to 10%) of fog at KAIA, KBFF, and
KSNY once again tonight after 09z. With limited confidence and a
pretty dry boundary layer this afternoon, will keep out of the TAF
for now. Will continue to monitor trends tonight and may amend
later.

&&

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

&&

$$

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