Cheyenne, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

166
FXUS65 KCYS 050525
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1125 PM MDT Sat Jul 4 2026

.KEY MESSAGES...

- Afternoon and evening storms, some of which may become strong
  to severe, will be possible this afternoon along and east of
  I-25.

- Sunday will be the driest day as an upper level ridge builds
  over the area.

- Hot temperatures expected Sunday and Monday, with highs
  topping out in the mid 80s to mid 90s.

- Conditional thunderstorm chances return Monday through at
  least Thursday in response to increasing moisture.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 1212 PM MDT Sat Jul 4 2026

A lovely Independence Day is in store under mainly sunny skies,
light winds, and temperatures soaring into the 80s to low 90s,
warmest primarily east of the I-25 corridor. Why the sunny skies
and warmer temperatures, well lets take a brief look aloft.
Some changes are in store over the next day or so with a ridge
building in from the south, this will be the dominant weather
feature in the short term period. Therefore, there has been some
changes in hi-res guidance from previous runs in the aerial
coverage of showers and thunderstorms for this afternoon. Latest
runs depict most of the activity initiating just outside of our
CWA. This is in part of model initialization of the shortwave
aloft a bit further east then what yesterday`s runs showed.
Now, the upper level shortwave will eject out earlier, meaning
an end to the threat of strong to severe storms. So, if a storm
develops in the environment we are in, the primary threat will
be large hail and gusty winds. Instability parameters have
decreased slightly from days prior with CAPE values of up to
1500 J/kg, this combined with bulk shear 0-6km of 30 knots, is
still capable to produce strong to severe storms. The bulk of
the activity should end by 7pm this afternoon. Be weather aware
just in case storms develop in your area.

Onto Sunday, well, as a strong upper level ridge builds expect a
benign weather day. The main weather story for Sunday will be
temperatures, with 700mb temps soaring to around 18 degrees C,
expect highs to top out in the upper 80s west of I-25 and mid to
upper 90s east of the corridor. What about the storm threat, well
with dry air aloft and subsidence, storm initiation will have a hard
time. This is due to the building ridge, so expect daytime
convection to be minimal as a result. This is more a reality due to
the lack of shear in the environment, so expect a pleasant
Sunday across the CWA.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 1212 PM MDT Sat Jul 4 2026

The long-term looks to be dominated by a stubborn upper level ridge
that will position itself over the four corners area. We will be on
the northern end of this ridge which may allow a few subtle
shortwaves to pass nearby to add some unsettled weather chances.
Otherwise, expect typical early summer time conditions to become
more prevalent through at least the next week.

Monday we can expect cirrus cloud cover and some chances at isolated
to scattered thunderstorms in the afternoon. A monsoon plume of
moisture is expected to move in from the west and increase PWAT
values. Subtle lifting from a shortwave may spark some high based
convection. A substantial dewpoint spread at the surface will mean
storms are going to be on the dry side. A risk of dry microburst is
possible with the mentioned thermo profile and over 1000 J/kg of
DCAPE available. Afternoon high temperatures look to be in the 80 in
the inner basins and in the mid to high 90s out in the Nebraska
Panhandle.

Tuesday through Thursday will keep the conditional afternoon
thunderstorm trend going. The plume of monsoon moisture will keep
PWATs elevated of 0.75 to 1.5" across the region. Enough low level
convergence will provide lift for thunderstorms. Additionally, bulk
wind shear of 35-45 knots may be enough to support more organized
convection and some severe risks. Machine learning models are
highlighting low end chances of severe weather through this period
from the GFS ensemble models.

Thursday through Saturday we will focus attention at elevated fire
weather concerns. The moisture that had kept relative humidity
values up may have advected east and out of the area by this time.
Minimum humidity values may drop into the teens and single digits
for the western counties Thursday and spread to be area wide Friday
and Saturday. High temperatures start rising as well. Some spots may
get close to reaching the triple digits for the first time this year
during this period. Winds should not be very strong in this ridging
regime which will help keep more widespread critical fire conditions
down. Fuels are starting to become critical in our western zones.
The rains we have gotten the last few weeks have induced flooding in
very localized spots and at least an inch in many places, however it
was not enough to offset the lackluster winter season we saw. As we
go into the hotter and drier portions of summer we anticipate fuels
to continue to cure and become more susceptible to combustion and
fire spread. Since this is fairly far into the forecast expect
changes to details.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1122 PM MDT Sat Jul 4 2026

VFR conditions expected over the next 24 hours. Winds generally
light and 10 knots or less overnight, becoming breezy tomorrow
morning into the afternoon with gusts of 20-30 knots from a
southerly to southeasterly direction. Skies clear overnight,
with FEW clouds at mid to high levels during the late morning
through afternoon hours.

&&

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

&&

$$

SHORT TERM...RZ
LONG TERM...RV
AVIATION...CG