283
FXUS65 KCYS 141153
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
550 AM MDT Tue Oct 14 2025

.KEY MESSAGES...

- Areas of locally dense fog may develop this morning near the
  I-80 summit and over the High Plains. More fog is expected
  late tonight and linger into early Wednesday morning.

- Another storm system will slowly move through the area late
  Wednesday through early Friday, bringing first showers and
  thunderstorms, following by chances of mountain snow and
  strong winds.

- A few strong thunderstorms are possible Wednesday afternoon
  across western Nebraska and far eastern Wyoming.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 330 AM MDT Tue Oct 14 2025

Current IR Satellite loop shows overcast skies across most of
southeast Wyoming and western Nebraska as low to midlevel
moisture moves north ahead of the Pacific upper level trough
currently moving onshore across the central Calif coastline.
KCYS radar loop shows widely scattered showers developing and
moving northeast. Can`t rule out some thunder this morning with
lightning detection observing a few strikes across northern
Colorado. Otherwise, precipitation is expected to be light with
the primary upper level shortwave, currently across central
Colorado, ejecting northeast into Nebraska later today. Behind
the shortwave, expect gradual clearing and precip coverage to
decrease through the afternoon. Other than some fog early this
morning and late tonight/early Wednesday, pretty quiet weather
with temperatures returning to the 60s today as a stationary
front lifts northward as a warm front by tonight.

For Wednesday, models indicate an interesting set-up across the
Front Range for mid October. Fog will slowly dissipate across
the high plains Wednesday morning as the warm front continues to
lift north. Further west, potent upper level trough will become
a closed low as it moves across the Great Basin region. High
temperatures will return to the upper 60s to even upper 70s
across portions of the Nebraska Panhandle. After a closer look
at area soundings: in my 15+ years living here, I don`t think
I`ve seen dewpoint Temps in the mid 50s across the high plains
this late in the season. Not surprising to see that NAEFS is
showing widespread 99th+ percentile PWATS across most of the
area Wednesday afternoon, and climatological maximums (for mid-
October) for mixing ratio/specific humidities. Therefore, there
is some concern of strong to marginally severe thunderstorms
for areas east of the I-25 corridor in additional to heavy
rainfall. High res CAMs show discrete tstorm cells developing
between the I-25 corridor and the WY/NE border Wednesday
afternoon and pushing northeast across the region. The HRRR is a
bit more aggressive, but the NAM and NAMNEST are on board too,
with most of the cells well north of I-80. Increased POP across
the area, but not sure how aggressive to go with the severe
threat given the time of the year...and questionable forcing.
Thermodynamic profiles look pretty good, with some areas closing
in on 1000 j/kg MLCAPE during the afternoon and plentiful
shear. However, dense cloud cover can have a big influence on
convective potential this time of the year. Overall, agree with
SPC`s Marginal Risk for far eastern Wyoming and the
northern/central Nebraska Panhandle.

For Thursday, all models show the upper level low lifting
northeast from the Salt Lake City area to far northern Wyoming
and southeast Montana by Thursday afternoon. Another round of
precipitation is expected on Thursday with strong jet energy out
ahead of the trough axis to the south of the upper level low.
Any thunderstorm activity looks to be in the morning, with rain
shower activity along the surface cold front, which could stall
across the eastern plains in the afternoon and evening. High
temperatures will return to below average on Thursday for most
areas with highs in the mid 40s to upper 50s. Winds are also
expected to increase with windy conditions looking more likely
across southeast Wyoming.


&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Updated at 245 AM MDT Tue Oct 14 2025

Most of the previous long range forecast remains on track. Made
additional adjustments to the wind forecast for late Thursday
night and Friday, mainly for the wind prone areas of southeast
Wyoming. In-house wind guidance is showing the potential for
strong winds for Arlington and Bordeaux...and possibly the I-80
corridor and portions of Carbon County after midnight late
Thursday night/Friday morning as the strong upper level trough
axis moves northeast across the region. Increased winds and
added gusts up to 55 MPH for now. 700mb subsidence is marginal,
so did not go into High Wind criteria quite yet.


Previous Discussion...
Issued at 222 PM MDT Mon Oct 13 2025

At the start of the long term, a pretty robust 500mb trough is
deep across the Western CONUS while ridging sits to our east
over the Central Plains. As we progress through the long term
period, the upper level trough will slide east into our CWA by
Thursday evening, continuing on a easterly track through the
weekend. So, what does all this mean for us, well, expect an
active pattern through mid-week with southwest flow pumping in
deep moisture. As the 500mb trough slips to our east by the
weekend, upper level flow will then become northwesterly. This
will bring in some changes, especially to the temperatures.
Expect cooler temperatures Friday into the weekend. Also, as
the cold front passes, another high wind event may be possible
Thursday into Friday. At the tail end of the long term period,
expect the coldest temps over the weekend while moderating some
on Monday as ridging aloft builds in.


&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 550 AM MDT Tue Oct 14 2025

Southwest flow aloft will continue today with a few rain showers
expected this morning. Areas of fog expected across far eastern
Wyoming and most of western Nebraska as a warm front lifts north
across the region.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail over the next
12 to 18 hours. There is a chance of some MVFR CIGS early this
morning for KAIA and KSNY, but should be short-lived.

For tonight, IFR/LIFR CIGS and VIS expected (confidence > 70%) at
KBFF, KSNY, KAIA, and KCDR after 04z Wednesday. Low stratus and fog
possible (~30%) at KCYS and KLAR after 06z Wednesday, but will keep
out of the TAF for now.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...RZ/TJT
AVIATION...TJT