053
FXUS65 KCYS 280010
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
600 PM MDT Wed Aug 27 2025

.KEY MESSAGES...

- Cool and wet pattern expected through Friday, with daily
  chances for precipitation and highs 5 to 15 degrees below
  average.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 234 PM MDT Wed Aug 27 2025

Radar has been active much of the day with scattered showers and
storms across the CWA. Ample cloud cover over much of the region has
lead to cooler temperatures, allowing for more stable air to settle
in place. Mesoanalysis shows MUCAPE to be less than or equal to 1000
J/kg over southeast Wyoming and western Nebraska. Little shear over
most of the area has lead to pulsey storms this afternoon. Given
little shear and instability, storms are not expected to be severe.
However, a few isolated storms could produce gusty winds and small
hail, mainly in the Nebraska panhandle where MUCAPE and shear values
are a bit higher due to less cloud cover. The main concern in storms
this afternoon and evening will be heavy rain. PWATs remain above
the 90th percentile of climatology for most of the CWA, prompting
the heavy rain threat. Model soundings indicate that cloud layer
winds will likely be quick enough and/or storms will be pulsey
enough for heavy rain to not linger over any one area for too long.
This should reduce any risk of flash flooding today. Light showers
will once again linger overnight with the disturbance over the
Pacific Northwest sending waves of vorticity maxes into
Wyoming.

The disturbance over the Pacific Northwest will gradually weaken and
begin to move eastward on Thursday. A minor shortwave will accompany
this disturbance. Once again, this will cause vorticity maxes to
traverse Wyoming and spark another round of showers and storms
during the afternoon. Based on Hi-Res guidance, coverage of
showers and storms will be less numerous than today. Model
soundings suggest non-severe storms as the area continues to
lack instability due to below average temperatures. Heavy rain
can also be expected in storms tomorrow as PWATs remain elevated
above normal.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 234 PM MDT Wed Aug 27 2025

Friday...Weak northwest flow aloft prevail, and with slightly warmer
temperatures as 700 mb temperatures rise to near 11 Celsius. Looks
like adequate low and mid level moisture for scattered afternoon and
evening showers and thunderstorms.

Saturday...For the penultimate day of August, northwest flow aloft
continues, and with plenty of low and mid level moisture available,
we expect scattered to numerous afternoon and evening showers and
thunderstorms. Cooler temperatures due to an increase in cloud cover
and precipitation coverage.

Sunday...Ridging aloft builds over western Wyoming, and with
atmospheric moisture decreasing and temperatures aloft increasing,
this day looks dry, with warmer temperatures compared to Saturday.

Monday...The ridge aloft continues amplified, which will effectively
keep it dry. The warming trend continues with 700 mb temperatures
near 14 Celsius.

Tuesday...Ridging aloft breaks down slightly as a shortwave trough
aloft moves across the region, and with a slight increase in low and
mid level moisture, we expect isolated to scattered late day showers
and thunderstorms.

Wednesday...Cooler temperatures expected after a cold frontal
passage. Looks like adequate low and mid level moisture to produce
scattered late day showers and thunderstorms.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 600 PM MDT Wed Aug 27 2025

Potent upper level disturbance will swing through the area this
evening, resulting in numerous showers and thunderstorms for far
eastern Wyoming and the southern/central Nebraska Panhandle.
Conditions are expected to improve after 06z, with some low clouds
and fog possible by sunrise Thursday.

HAZARDS/WEATHER TRENDS: Showers and thunderstorms will impact KLAR,
KRWL, and KCYS over the next 6 hours through 06z. Although VFR
conditions will prevail, MVFR CIGS and VIS are possible along with
some occasional lightning in the vicinity. For western Nebraska,
another strong line of thunderstorms is forecast to impact KBFF and
KSNY before 02z. This line has the potential to produce brief +RA
and IFR conditions.

After 06z, low CIGS and fog are possible (25% to 35%)...mainly at
KAIA and KSNY between 08z to 14z Thursday morning.

&&

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

&&

$$

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