Douglas, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

527
FXUS65 KCYS 200813
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
213 AM MDT Thu Aug 20 2026

.KEY MESSAGES...

- Hot and dry conditions will persist through the end of the
  week with Friday likely being the hottest day out of the next
  several.

- Elevated to near-critical fire concerns expected Thursday and
  Friday, though Red Flag criteria is currently not expected to
  be met.

- Daily shower and storm chances return Monday through the end
  of the week with slightly above average temperature expected
  until Thursday.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 212 AM MDT Thu Aug 20 2026

Upper-level ridging will persist today as the ridge builds
throughout the day. 500mb flow remains benign, but a few vorticity
maxima will eject across the region this afternoon. Clear skies this
morning look to become partly cloudy as these vorticity maxima
general clouds across the region. Westerly to northwesterly flow
persists at 700mb this afternoon with GFS Omega fields suggesting
weak downward motion along the Laramie Range. This downsloping will
continue to dry out the lower levels today making precipitation
chances near zero for the afternoon. 700mb temperatures will warm
into the 14 to 19C range this afternoon, leading to surface
temperatures soaring into the mid-80s to mid-90s across the entire
CWA. Thankfully, surface gradients are progged to remain minimal,
decreasing the potential for Red Flag criteria winds across the
region. Afternoon minimum humidity values will drop into the 12 to
22 percent range, but relatively calm winds and several days of
moisture will prevent critical fire danger this afternoon.

Similar to Thursday, upper-level ridging strengthens on Friday as
the upper-level ridge drifts eastward and remaining directly
overhead. The ridge axis will be just off to the west of the CWA,
but very warm temperatures are still anticipated. 500mb flow remains
benign once more with multiple vorticity maxima ejecting across the
CWA, once more increasing cloud cover into the afternoon hours.
Weak, westerly 700mb flow persists throughout much of the day
Friday, with omega fields once again suggesting modest downsloping
throughout the afternoon hours. 700mb temperatures will increase to
the 15 to 19C range on Friday as the upper-level ridge creeps closer
to the region. As a result, surface temperatures will skyrocket into
the upper-80s to upper-90s, with a few sites near 100F, Friday
afternoon. Afternoon minimum humidity values will once again drop
into the 15 to 25 percent range across the region with winds once
again remaining reactively light and, therefore, reducing fire
concerns for Friday afternoon. There is a small chance for an
isolated shower or storm to develop off the Laramie Range, but PoP
values remain only at 15 percent for a small portion of the area
between Cheyenne and Laramie. A very weak cold front will push into
the region Friday evening into the overnight hours and drop 700mb
temperatures by a couple degrees and flip the 700mb flow to a more
easterly component. Resulting easterly flow at the surface Saturday
morning may result in some low clouds or fog, but these will first
need to overcome the very dry conditions expected due to continued
downsloping Friday afternoon.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 212 AM MDT Thu Aug 20 2026

Upper-level ridging continues to dominate the long term weather
pattern, with models suggesting the ridge starting to breakdown
Monday evening into the overnight hours Tuesday. For Saturday, the
ridge will be planted directly overhead with much stronger 500mb
vorticity maxima ejecting across the CWA. 500mb flow also suggests
that monsoonal moisture will start to return to the area Saturday
after being largely cutoff by the developing upper-level ridge.
Behind the weak cold front moving through the region Friday
afternoon and evening, 700mb temperatures will drop into the 14 to
16C range with 700mb flow flipping more southerly across the region
ahead of an incoming 700mb shortwave trough. Weaker easterly flow is
expected mid-day Saturday before surface pressure gradients start to
increase into the afternoon hours, resulting in increasing easterly
winds across the region. Surface temperatures will be cooler than
Friday, in the low-80s to low-90s across the region. Easterly
surface flow combined with the return of some monsoonal moisture and
the forcing provided by the incoming shortwave trough will help
initiation showers and storms along the Laramie Range into the
evening and overnight hours. Thanks to this returning moisture,
precipitable water values will increase to the 97.5th percentile,
just over an inch for much of the CWA. Therefore, showers and storms
on Saturday may produce heavy rain, which will act to further limit
fire weather concerns through the weekend.

A slightly more dynamic setup is expected Sunday as the upper-level
ridge continues to push easterly before flattening out by Monday
afternoon. Westerly to southwesterly flow aloft is anticipated as
the ridge advances eastward with multiple 500mb vorticity maxima
pushing through the region. 500mb flow continues to support the
return of monsoonal moisture region with westerly flow developing at
500b with a fetch all the way to the Pacific Ocean just off the
coast of southern California. NAEFS Mean Precipitable Water
continues to suggest PWs in the 97.5th percentile across the region
Sunday, which is favorable for heavy rain across the region. The
700mb shortwave trough will continue to push easterly Sunday morning
into the evening hours, taking with it the best forcing. A 700mb
ridge starts to build off to the south and west after the shortwave
pushes out of the region with westerly flow developing across the
CWA. Isolated to scattered showers and storms may develop mid-day
and continue through the evening hours Sunday, despite ridging
remaining aloft and the best forcing well off to the east. Sunday
will be warmer than Saturday as 700mb temperatures increase until
the advancing ridge, with highs expected to be in the mid-80s to mid-
90s once more.

A brief period of zonal flow aloft develops for Tuesday and most of
Wednesday before another ridge begins to build across the western
CONUS starting Wednesday and continuing through the end of the week.
700mb flow remains largely calm during the week. Several 500mb
vorticity maxima will push across the region as the monsoonal
moisture fetch remains open across the region. Daily shower and
storm potential is expected Monday through much of the week, with
heavy rain possible each day. Temperatures will be warm for most of
the week, but not overly hot. Daily high temperatures will be in the
low- to upper-80s through Wednesday. As the ridge begins to build
back over the region Wednesday and Thursday, temperatures start to
increase with high temperatures in the mid-80s to mid-90s expected
to return by Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1043 PM MDT Wed Aug 19 2026

VFR conditions over the next 24 hours, with SKC or FEW CIGS at
high levels. Winds light, generally less than 10 knots and
variable as winds shift throughout the day, though some stronger
winds may be possible for KLAR & KRWL from W to NW direction.

&&

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

&&

$$

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