FXUS65 KCYS 090510
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1110 PM MDT Wed Jul 8 2026

.KEY MESSAGES...

- Slight Risk of severe thunderstorms this afternoon and Thursday
  with heavy rainfall, hail, and strong gusty winds possible.

- A ridge builds into the long term, drying the area out and 
  developing Red Flag and potential heat advisory conditions 
  through next week.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 125 PM MDT Wed Jul 8 2026

As of this afternoon the dryline is noted on radar right around
the I-25 corridor and retreating westwards into Cheyenne proper.
Development has begun along this boundary with a few storms
noted, but nothing strong currently. Forecast sounding profiles
across the region note inverted V's, which combined with DCAPE
values into the 1000-1500 J/kg range would be indicative of 
high based storms with strong wind gusts the primary hazards.
That being said, there is a little bit of instability across the
region, and some meager support for updrafts, so we can't rule
out a storm or two to have at least some hail, whether it be
severe in size or small accumulating hail. Finally, moisture is
actually notably plentiful east of I-25 despite the dry surface,
with PWAT values into the 1-1.5" range. With the scattered
nature of storm development, if any we get multiple stronger
storms training over the same location, a marginal risk of
excessive rainfall will be possible. Storms will continue into 
the early evening, but by around 8-9 PM storms should be on the 
decline as support wanes.

Moving into Thursday, our severe risk continues once again along
and east of the I-25 corridor, but this time profiles will
support a bit more organization to storm development. Initial
storms should go up during the early afternoon with steep mid-
level lapse rates and modest instability around 1000-2000 J/kg,
which would support isolated storms capable of both large hail 
and damaging winds. This batch of activity though will likely 
grow upscale into a more linear feature, which will shift the 
primary hazard into mostly strong winds as storms evolve into 
western Nebraska. And like today, PWAT values into the 1-1.5" 
range should fuel at least a meager risk of localized flooding. 
Once again as the sun goes down we'll see storm activity wane 
and/or move out of our area.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 125 PM MDT Wed Jul 8 2026

Friday...The atmosphere dries out somewhat compared to today and 
Thursday, with shortwave ridging aloft bulging over eastern Wyoming. 
The 12Z GFS indicates decent low and mid level moisture for far 
southeast Wyoming and the Nebraska Panhandle, and diurnal heating 
and low level mechanical lift, along with a passing perturbation, 
will likely produce isolated late day showers and thunderstorms from 
I-25 eastward, and we may see our POPS and thunderstorm coverage 
increase somewhat in the next few model runs and days.

Saturday through Wednesday...Ridging aloft dominates our region, 
with quite dry air at low and mid levels, accompanied by 700 mb 
temperatures from 14 to 21 Celsius, thus chances for late day 
showers and thunderstorms will be nearly nil and non existent, and 
dry weather will prevail. The 700 mb temperatures will yield maximum 
temperatures in the 90 to 105 degree range. A weak perturbation and 
a slight increase in mid level moisture may spark isolated 
thunderstorms on Tuesday, and moreso on Wednesday, along the 
convective inhibition aloft gradient along the I-25 corridor and 
further to the west.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1108 PM MDT Wed Jul 8 2026

Showers continue to move off to the east, currently only
impacting the KAIA terminals with light rain. Mostly cloudy
skies continue across western Nebraska for the next 1 to 2 hours
before clearing out into mostly clear skies overnight. With all
the precipitation this evening, isolated, patchy fog may develop
at KLAR, KCYS, KBFF, KSNY, and KAIA overnight into the early
morning hours. Included TEMPO groups to cover this threat,
though confidence is low at this time. Another round of showers
and thunderstorms returns in the afternoon, with gusty and
erratic winds expected in and around any showers or storms that
develop.

&&

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

&&

$$

SHORT TERM...CG
LONG TERM...RUBIN
AVIATION...AM