572
FXUS65 KCYS 050932
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
332 AM MDT Fri Sep 5 2025

.KEY MESSAGES...

- Below average temperatures with lingering smoke possible on
  Friday.

- A warming trend will develop for the Saturday through Thursday
  period, with chances for isolated to scattered late day
  showers and thunderstorms each day.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 238 AM MDT Fri Sep 5 2025

A cold front that moved through earlier has left lingering light
showers across southeast Wyoming and western Nebraska. These showers
will continue through the early morning hours per Hi-Res guidance,
but will not pose much of an impact besides getting the ground wet.
The deep trough responsible for the cold front will sit over the
north-central part of the country through Friday, leading to cool,
below average temperatures for the beginning of September. With 700
mb temperatures in the lower single digits, highs today will only be
in the 60s to low 70s, which is about 10 to 12 degrees below
average. For the most part, the cooler weather and trough will keep
precipitation chances pretty minimal today, however, cannot rule out
a few high terrain showers developing during the afternoon. Besides
the cooler and drier weather, the cold front was temporarily able to
clear out some of the near surface smoke from Canadian wildfires.
Unfortunately, near surface smoke is likely to re-enter areas west
of the Laramie Range during the afternoon. Once clouds clear out,
most of the CWA will still see hazy skies on Friday from smoke
aloft. Expect quiet conditions heading into Friday night.

Most of the CWA will wake up to a chilly, fall like morning on
Saturday with lows in the upper 30s to low 40s. A few isolated areas
in the northern Nebraska panhandle and Converse and Niobrara
Counties could develop patchy frost given calm, clear conditions
overnight combined with lows in the upper 30s. Any frost that
develops will likely be brief as temperatures will quickly warm up
as mostly sunny skies dominate most of the CWA. The upper-level
trough that was over the north-central part of the country will push
eastward into the Great Lakes Region, opening the door for weak
ridging to develop over the Great Basin. This will allow 700 mb
temperatures to begin to warm up into the double digits, bringing
highs into the 70s. A weak shortwave will also begin to move into
western Wyoming and Colorado, potentially leading to a slight chance
in scattered showers and storms developing in the afternoon for
areas west of the Laramie Range.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 200 PM MDT Thu Sep 4 2025

Saturday...Northwest flow aloft continues with a slow warming trend
as 700 mb temperatures rise to near 8 Celsius. Looks like enough
residual moisture over the far southern Snowy Range and far southern
Laramie Valley for isolated afternoon showers and thunderstorms.

Sunday...As ridging aloft develops over our counties, return
southeast low level flow develops, advecting low and mid level
moisture across our counties, and producing scattered afternoon and
evening showers and thunderstorms, mainly west of I-25. The warming
trend continues with 700 mb temperatures near 10 Celsius.

Monday...The warming trend continues with low amplitude ridging
aloft and 700 mb temperatures rising to near 14 Celsius. Adequate
low and mid level moisture for isolated late day showers and
thunderstorms mainly west of I-25.

Tuesday...As the ridge aloft transitions over the Central Plains
states and our flow aloft turns southwest, temperatures will remain
about the same. Enough low and mid level moisture for isolated to
widely scattered late day showers and thunderstorms, mainly west of
I-25.

Wednesday...Southwest flow aloft strengthens, and with warm
temperatures aloft providing convective inhibition, only isolated to
widely scattered late day showers and thunderstorms will be
possible, mainly west of I-25. High temperatures about the same as
on Tuesday.

Thursday...South southwest flow aloft prevails, and with adequate
low and mid level moisture, we expect to see isolated to widely
scattered late day showers and thunderstorms. Perhaps slightly
cooler compared to Wednesday due to more clouds and
precipitation.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 331 AM MDT Fri Sep 5 2025

Lingering low to mid-level clouds will continue this morning, with
most terminals clearing out by mid-afternoon. KLAR and
potentially KCYS could experience MVFR CIGs early this morning,
but these should lift fairly quickly as wind speeds increase.
Aviation concerns throughout the rest of the day will be fairly
minimal, however smoke aloft will be possible across southeast
Wyoming and western Nebraska.

&&

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

&&

$$

SHORT TERM...SF
LONG TERM...RUBIN
AVIATION...SF