539
FXUS65 KCYS 151200
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
500 AM MST Sat Nov 15 2025

.KEY MESSAGES...

- A High Wind Warning remain in effect for the Arlington/Elk
  Mountain and Bordeaux wind prone regions until 500 AM this
  morning.

- 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 MONDAY/...
Issued at 245 AM MST Sat Nov 15 2025

Current observations across southeast Wyoming show locally
strong winds continuing across a few of the wind prone areas
early this morning with gusts of 65 mph and 60 mph reported near
Arlington and Bordeaux respectively. Will keep the High Wind
Warning going for these two zones until 500 AM, with low level
pressure gradients slowly weakening by sunrise. Not expecting
to add any zones to the warning at this time, although the I-80
Summit has been close a few times in the last 5 hours. Otherwise,
relatively mild temperatures will continue early this morning
due to westerly winds and cloud cover. Another pleasant day on
Saturday with mild temperatures for this time of the year. It
will be a little more breezy across southeast Wyoming and
temperatures will be a few degrees cooler...with highs in the
60s for southeast Wyoming and upper 60s to low 70s for western
Nebraska.

Significant change in the weather pattern still expected over
the next week or two, but the shift will be slow and likely
start the first phase beginning on Sunday and Monday. Models
continue to show a significant upper level trough, which is
producing widespread rainfall across central and southern
California with heavy snow across the Sierra Nevada range today,
lifting northeast into Colorado and Wyoming by late Sunday
night and Monday. All models indicate the upper level low
becoming a negatively tilted open waved trough as it moves
across the region. Rain and some snow is expected to return to
southeast Wyoming and western Nebraska. Locally strong gusty
winds are looking more likely behind the cold front early Monday
morning. Not looking like a major precip event since the trough
becomes pretty progressive and is forecast to exit most of the
region by late Monday afternoon. Snow levels are forecast to
drop to around 7500 feet, so maybe some rain/snow mix down to
6500 feet with little or no accumulation for Rawlins, Laramie,
and Saratoga. ECMWF is the coldest, but still shows 700mb
temperatures near -4c at minimum. Expect most of the lower
elevations to see precip amounts lower than 0.20 of an inch,
with amounts closer to a half inch in the mountains. May need a
Winter Weather Advisory for the mountains with some decent
frontogenesis located over Carbon/Albany counties Late Sunday
night/early Monday morning. May see a few hours of snowfall
rates around 1 inch/hour. However, with the rapid motion of the
system combined with some of the snow occurring during the day,
forecast confidence is limited in 6+ inch snow amounts. So will
hold off on any Winter Weather Advisories for now. Kept POP
above 50% to 60% for Sunday night, with rain/snow tapering off
by noon Monday.

As for winds, will wait for the current wind event (early
Saturday morning) to expire before focusing on the potential for
strong winds early Monday morning. Looks like a potential Bora
event behind the cold front after midnight Sunday night into the
early morning hours. In-house wind guidance shows the
probability of strong winds around 60% for the wind prone areas,
but significantly less in the high plains and high valleys. The
event looks surface gradient driven at the beginning, with 700mb
winds lagging the peak surface gradient. In fact, the 00z GFS
shows 700mb winds below 50 knots and mediocre low level
subsidence through early Monday morning. The Canadian is more
aggressive with the winds and shows better forcing, so will
continue to monitor this weekend. Increased winds in the wind
prone areas to near High Wind criteria. Kept breezy to windy
conditions elsewhere (20 to 35 MPH) for now.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Issued at 128 PM MST Fri Nov 14 2025

Moving into the rest of the long term, high pressure ridging
should return to control our area through the middle of next
week, with another low then incoming to end the week and into
next week. Current guidance does keep this system well to our
south though with weaker troughing moving over our area in lieu
of the stronger low itself. Still this pattern should allow for
a fairly steady stream of moisture and produce some chances of
precipitation through the end of next week while our
temperatures steadily decline through next Thursday. By that
point, the majority of the region should be back to near normal
highs, ending our warm streak as weak move into the later part
of November where current climate outlooks suggest we could get
even colder leading into Thanksgiving. Overall there is moderate
confidence (40-50%) in the forecast as ensembles begin to
diverge in the strength of the systems moving into the later
part of the long term, brining more uncertainty to the end of
next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 500 AM MST Sat Nov 15 2025

Gusty winds expected today, especially across the southeast Wyoming
terminals, with some low wind shear until 15z. Otherwise, a pretty
quiet day is expected with FEW-SCT high clouds until late this
evening.

HAZARDS/WEATHER TRENDS: 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...High Wind Warning until 5 AM MST early this morning for WYZ106-
     110.
NE...None.

&&

$$

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