857
FXUS65 KCYS 022007
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
207 PM MDT Sat Aug 2 2025

.KEY MESSAGES...

- There is a Slight Risk (Level 2 of 5) for severe weather
  Saturday afternoon and evening east of the Laramie Range. All
  modes of severe weather are possible: large hail, damaging
  winds, an isolated tornado or two (southern Panhandle), and
  flash flooding.

- There is a Marginal to Slight Risk of severe weather for
  Sunday, mainly across western Nebraska. Primary hazards look
  to be large hail, damaging winds, and flash flooding.

- Drier and warmer conditions return mid-week and continue
  through the weekend.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 105 PM MDT Sat Aug 2 2025

Thunderstorms already firing off once again across the region
this afternoon and the potential for severe weather remains yet
again. Stout instability of 1500-2500 J/kg lies from around
Cheyenne eastwards, while favorable SRH lies just outside of our
region to the west of the NE Panhandle. Overall the environment
looks conducive of some stronger to severe thunderstorms
including large hail and damaging wind gusts, but unlike
yesterday we`re not seeing quite as widespread stout severe
parameters and with much of this activity firing off in a
scattered nature, congealing of storms into clusters will help
to limit supercellular development. The best region in our CWA
for stronger severe weather development will be the Southern
NE Panhandle, where a watch is possible in the coming hour or
two. Meanwhile mesoanalysis also shows PWAT values of 1+ inch
more into central Nebraska. This has helped to pull the
Panhandle just out of the marginal risk of heavy rainfall, but
some localized flooding can`t be ruled out despite our downturn
of flash flooding threat.

CAMs indicate activity will either begin to weaken or move out
of region during the early evening hours. Overnight more
clearing should occur, and with downsloping expected low stratus
and fog should finally not be an issue for the Nebraska
Panhandle. Into tomorrow the Nebraska Panhandle remains in a
Marginal (1 out of 5) risk for severe weather including hail and
winds yet again. CAMs struggle to produce meaningful storms in
Wyoming as moisture and instability continue to shift eastwards
further into Nebraska. MUCAPE values of 750-1000 J/kg should
still be present in the NE Panhandle and with bulk shear values
a bit stronger in the 50-60 knot range, there should be at least
meager support for a stronger storm or two during the afternoon.
Meanwhile a drier surface layer may support some sounding
profiles supportive of gusty showers or storms in Wyoming.
Overall this weekend is thankfully looking quieter than our end
to the week was, but a low end risk of some stronger to severe
storms still can`t be ruled out.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 105 PM MDT Sat Aug 2 2025

Warmer and drier weather is still expected in the long term forecast
for Monday onwards. However, there is currently a Marginal Risk for
severe weather across eastern portions of the region on Monday, due
to northwesterly flow aloft allowing a weak disturbance to push
through the flow and initiate enough synoptic lift via a stream of
strong vorticity to support a few moderate to high based showers and
possibly some isolated severe storms. Monsoonal moisture attempts to
return the region as highlighted by NAEFS projecting Integrated
Vapor Transport to be in the 99th percentile for the Intermountain
west. The latest model soundings aren`t too impressive and look to
indicate wind as the main severe threat. Storm chances are expected
to drop off Tuesday as an upper-level ridge builds over the
southwestern CONUS and subsidence returns to southeast Wyoming and
western Nebraska. PWATs are expected to be in the 10th percentile
and gusty returning to the region to bring some Fire Weather
concerns Tuesday. This high is expected to remain firmly in place,
leading to more zonal flow across the region throughout the week.
With the ridge so close by, its influence will be felt as
temperatures once again rise into the 90s to near 100s. The warmest
day looks to be Thursday at this time, though Wednesday through
Friday will be quite hot. The next best chance for precipitation
will be Saturday as an upper-level trough attempts to dive south out
of Canada. However, this is still a week away, so things will
change. This potential trough will continue to be monitored
throughout future forecast updates.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1151 AM MDT Sat Aug 2 2025

VFR conditions expected to prevail over the next 24 hours.
Another round of thunderstorms possible once again locally
impacting both winds and visibilities as well as bringing MVFR
or lower conditions for a brief period, with strong to severe
activity primarily impacting Southern and Central Panhandle
terminals this afternoon (KSNY, KBFF, KAIA) though all sites
could see thunderstorms nearby. Cloud decks should be generally
mid height, between 5-15k feet, but locally lower decks with
storms also possible. Predominant winds 10-20 knots with some
gusts to 30 knots possible, lessening overnight into tomorrow
morning.

&&

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

&&

$$

SHORT TERM...CG
LONG TERM...MM
AVIATION...CG