425
FXUS65 KCYS 300848
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
248 AM MDT Tue Jun 30 2026

.KEY MESSAGES...

- Elevated fire weather conditions will continue for much of the
  week ahead. Red Flag Warnings in effect east of the Laramie
  Range for Tuesday afternoon.

- Scattered thunderstorms late Tuesday evening will have the
  potential to become strong to severe, mainly in the central
  and southern Nebraska panhandle.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 245 AM MDT Tue Jun 30 2026

A mixture of both fire weather and scattered showers and
thunderstorms will be possible today as an upper-level shortwave
traverses the CWA. Ahead of the shortwave, dry air will exist in the
low and mid-levels, leading to low relative humidity at the surface
for most of the forecast area. With the incoming shortwave, an
increase in wind is also expected. The combination of dry and breezy
conditions will produce elevated to near critical fire weather
concerns. This will primarily be for areas east of the Laramie Range
where fuels are deemed dry and critical. As a result, Red Flag
Warnings have been issued for this area for Tuesday afternoon.
Humidity will begin to increase later in the afternoon as
precipitation chances also increase. With the shortwave expected to
enter the CWA this evening, storms will likely get a later start,
with development by late afternoon. Hi-Res guidance shows scattered
showers and storms continuing through about midnight, with a few
lingering showers possible after that. Model soundings actually show
a good amount of instability overnight, allowing storms to continue
past sunset. Cannot rule out an isolated strong to severe storm or
two. With the dry surface, model soundings show deeply inverted-V
profiles. This will lead to elevated DCAPE values in excess of 900
J/kg for most locations east of the Laramie Range. DCAPE values of
this magnitude could lead to severe wind gusts in any storms that
develop. Cannot rule out large hail in storms, however, MUCAPE
values are not as impressive.

Looking at a fairly benign day on Wednesday with temperatures
similar to Tuesday. Highs will be in the 70s and 80s with mostly
sunny skies. Another dry day is expected as more dry air aloft moves
in behind the shortwave. Relative humidity with be in the low teens,
however, wind will be a limiting factor in any critical fire weather
conditions. Cannot rule out a slight chance of showers Wednesday
evening, however it will likely be too dry for much, if any,
precipitation to reach the ground.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 303 PM MDT Mon Jun 29 2026

As we progress past Tuesday, we become stuck in Southwest flow
on the front side of this ridge. The warm, dry, but smokey air
from the Desert southwest and the Colorado/Utah fires will be
filtering over the area for the remainder of the week. This will
limit our rain chances as this dry air removes all the moisture
from the surface and lower dewpoints and RH values. The models
have a few shortwaves pushing into the region past Tuesday but
with no moisture and very limited forcing there isn`t much
confidence these waves will do anything beside increase our
gradient and produce the normal amount of wind through our area.
Fire weather will be the biggest concern as our fuels will
enter a curing state once again despite our stormy 7 days last
week. Winds will be light to marginal so it may be difficult to
reach Red Flag criteria for most of our area despite the low RH
and curing fuels. There is another trough that may move through
Friday night into Saturday morning for a possibly wet start to
our 4th of July weekend plans. Looking at the global models,
each one has a different intensity of forcing but there is a
general uptick by the models compared to yesterday. While it
still doesn`t look to be a strong four corner low, the shortwave
trough may be strong enough to overcome the dry air and give us
some measurable precipitation. Given it is the 4th of July, we
will be monitoring this set up closely and try to narrow down
timing and locations for everyone.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1055 PM MDT Mon Jun 29 2026

VFR conditions will dominate across all terminals for the duration
of this TAF period. Winds overnight will be on the lighter side as
they become and remain generally less than 10 knots. However, this
is short-lived as winds will ramp right back up Tuesday to around 25-
30 knots, by 19Z for the Wyoming terminals and by 22Z for the
Nebraska sites. This too won`t last all that long as winds towards
the tail end of this forecast period will once again be trending
downward.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from 11 AM this morning to 7 PM MDT this
     evening for WYZ417-418-430>433.
NE...Red Flag Warning from 11 AM this morning to 7 PM MDT this
     evening for NEZ434>437.

&&

$$

SHORT TERM...SF
LONG TERM...MM
AVIATION...RZ