809
FXUS65 KCYS 020506
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1106 PM MDT Fri Aug 1 2025

.KEY MESSAGES...

- There is a Slight Risk (Level 2 of 5) for severe weather
  Friday afternoon and evening east of the Laramie Range. All
  modes of severe weather are possible: hail, winds, tornadoes,
  and flash flooding.

- There is a Marginal Risk of severe weather for Saturday,
  mainly across western Nebraska. Primary hazards look to be
  hail, wind, and flash flooding.

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

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 118 PM MDT Fri Aug 1 2025

Another day of severe weather expected across the region but
ingredients are a step above yesterday`s leading to a bit more
concentrated threat of severe weather across the region.
Current mesoanalysis is showing another moist environment with
PWAT values of 0.8-1.2 inches, while severe parameters include
MUCAPE maxing out at 3500 J/kg near the WY/CO/NE borders, bulk
shear values of 25-30 knots, and effective SRH of 100-150 m2/s2.
This is leading to an environment supportive of large hail,
strong winds, and perhaps even an isolated tornado or two. With
supercell composites of 2-4 from the Laramie Range and
eastwards, it seems all but certain we should see some stronger
thunderstorms into the mid to later part of the afternoon and
evening, and the expectation is that we should see a severe
thunderstorm watch within the next few hours with strong to
severe activity likely through the evening hours. With some of
these storms dropping rainfall rates of 1-2+ inches per hour, a
flooding risk cannot be ruled out as well.

Moving overnight activity should wane after the sun sets or move
out of the region, leading to a quiet evening. Tomrorow`s setup
remains similar as it has been the past several days with the
best moisture axis continuing to pivot a bit more south and
eastwards. While we`ll still remain in at least a marginal risk
for stronger to severe storms for our easternmost zones, the
best threat should be just south of the WY/NE border. And this
becomes apparent in our RH values as afternoon minimums descend
back below 50% for our eastern zones, while western zones remain
entrenched in the teens to 20% range. CAMs show a bit more
scattered activity looking less potent compared to today`s, but
enough instability should bring another risk of at least
isolated strong to severe storms.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 159 AM MDT Fri Aug 1 2025

Sunday onwards looks to be hotter and drier across much of the
region as an upper-level ridge move into the Intermountain West and
the moisture fetch from the Pacific Ocean dissipates with the
disruption from the ridge. 700mb temperatures will surge back into
the 17 to 20C range by mid-week, leading to much warmer temperatures
mid-week onwards as the ridge remains in place overhead. Wednesday
and Thursday look to be the hottest day of the week with low- to
upper-90s returning to much of the area as 700mb temperatures rise
into the 18 to 20C range once more. With the warmer and drier
conditions, fire weather concerns will return mid-week, especially
in locations that do not see rainfall over the next couple of days.
The next best chance for precipitation will be next weekend, as an
upper-level trough and subsequent 700mb low are progged to move into
the region. However, this is still over a week out and this
potential will likely change over the next several forecast
packages. Overall, looks like another hot and dry week for much of
southeast Wyoming and western Nebraska.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1104 PM MDT Fri Aug 1 2025

Clearing skies expected over the next 1 to 2 hours across
western Nebraska, with mostly light winds near the surface.
Light and variable winds expected across southeast Wyoming.
There is another chance for patchy fog developing along and east
of the Laramie Range, but confidence is low at this time.
Additionally, low ceilings will be possible overnight, with
surface winds not favorable for fog development.

&&

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

&&

$$

SHORT TERM...AM
LONG TERM...MM
AVIATION...AM