721
FXUS65 KCYS 090800
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
200 AM MDT Sun Aug 9 2026

.KEY MESSAGES...

- Red Flag Warning remains in effect through 9 PM Sunday for
  all of southeast Wyoming for very low humidities and
  significant gusty winds.

- Elevated to critical fire weather conditions will likely
  persist into the early work week, with further Red Flag
  Warnings likely needed each day.

- Hot temperatures continue through the start of the week before
  a pattern change begins to occur as precipitation chances
  start to rise and temperatures fall, dropping to below normal
  by the later half of the week.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 200 AM MDT Sun Aug 9 2026

Sunday and Monday will look almost identical to each other as we
see the ridge over the Four Corners area flattened by a pair of
shortwaves passing across our area each day. Under this pattern,
temperatures will be largely similar, with widespread highs in
the upper 80`s to upper 90`s, with a few triple digit highs also
possible for our easternmost counties. These warm conditions
will help to produce a notably dry surface layer as daytime
minimum RH values continue to descend into the teens. Another
critical day is expected on Sunday, with Red Flag Warnings
remaining in effect through 9 PM. On Monday, we may see a
smaller critical environment and a more widespread elevated
environment, and overnight recoveries should be much better
compared to the past couple of days. Therefore will likely
analyze and issue fresh warnings overnight into Monday morning
based on what locations can see strong enough winds to go along
with the dry surface. Finally, as we saw yesterday, even the
high based thunderstorms that we develop can take advantage of
their environment. Expect a bit more widespread coverage on
Sunday as compared to Saturday, with most storms still remaining
gusty virga showers alongside potential dry lightning, but with
DCAPE values into the 1500-2000 J/kg range and PWAT values at
or just above average, a strong to severe thunderstorm capable
of producing some hail alongside the gusty winds cannot be ruled
out. Best environment once again will be our easternmost
counties into the Nebraska Panhandle. Monday afternoon and
evening may be similar in coverage, with CAMs indicating an
uptick in potential compared to ensemble guidance. For now, did
some slight adjustments to POPs on Monday, and ramped them up
dramatically for today, with the same thing likely needed
tomorrow night. Because of the dry lower levels though, have
kept QPF minimal. Also added plenty of smoke into the forecast
alongside our Air Quality Alert valid through Monday, with high
resolution guidance showing a clearing into Monday morning but a
fresh push of PacNW smoke later in the day.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 256 PM MDT Sat Aug 8 2026

This long-term forecast period will continue a suppressed ridge
pattern. The 500mb jet keeps stationed over the PNW and into the
Rockies and high plains areas of Montana through northern Wyoming.
Precipitation chances increase as the week goes on, with PWAT values
increasing daily. Wednesday through Friday looks to be the best
chances of precipitation. Severe weather does not appear to be a
threat at this time in southeast Wyoming due to mostly light
westerly flow in the mid and upper levels. Nebraska on the other
hand has better chances of severe weather. As the ridge pushes south
and suppresses, faster flow aloft moves in. Wind shear values look
to be around 30-40 knots which have the potential to produce
multicellular storms. Warm conditions continue through most of
this long-term period, but with those precipitation chances mid
- end week, temperatures likely will likely be lower than
earlier in the week. 700mb temperatures show ranges from the
teens to mid-teens, supporting a cooler end of the week. Fire
weather will continue to be a concern through Monday with low
RHs and some gusty winds. With precipitable water, RHs, RH
recoveries, and precipitation chances increasing throughout the
week, fire weather concerns fade away.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1142 PM MDT Sat Aug 8 2026

Lighter winds are expected overnight with intermittent mid-level
cloud cover moving through. There remains about a 30% chance for low
clouds developing at AIA between about 09z and 15z. Started to hint
at this, but confidence was too low to add as a prevailing group.
Will need to monitor for possible AMDs if humidity rises faster than
expected.

For Sunday, look for westerly wind gusts returning to southeast
Wyoming terminals, while winds rotate to northeast, then southeast
in western Nebraska. Widely scattered high-based showers and
thunderstorms are expected again Sunday afternoon and evening.
Coverage and likelihood of impacts due to gusty/erratic winds and
vicinity lightning will be higher than Saturday. This remains at a
PROB30 group for now. Activity will be mainly between 19z and
02z.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Air Quality Alert until noon MDT Monday for WYZ101>119.
     Red Flag Warning until 9 PM MDT this evening for WYZ417>433.
NE...None.

&&

$$

SHORT TERM...CG
LONG TERM...ML/AM
AVIATION...MN