021
FXUS65 KRIW 030854
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
254 AM MDT Sun Aug 3 2025

.KEY MESSAGES...

- Showers and thunderstorms again today, but will be much more
  isolated and limited to far NW WY.

- Isolated showers linger Monday across northwest Wyoming.

- Increasing fire weather concerns building through the
  upcoming week. Red Flag Warning already posted for southern
  Wyoming for Monday.

&&

.DISCUSSION...
Issued at 230 AM MDT Sun Aug 3 2025

The H5 ridge continues to build across the greater Four Corners
region, but remaining local moisture will still bring some
showers during the afternoon. The next shortwave will be able to
tap enough remaining moisture to spark a few showers and
thunderstorms mainly for Teton and Park Counties during the few
hours around peak heating this afternoon. Some daytime CU will
also build along the Bighorns, but chances for accumulating
precip there will be minimal. The remainder of the area will see
mostly sunny skies and continued warm temperatures in the mid
to upper 80s.

After today, most of the state transitions into a drier, more
fire-weather concerning regime, as desert air pushes in from the
southwest. Shortwaves will continue to sweep around the northern
edge of the ridge, but will get pushed farther north. They will
be close enough, though, to tighten the gradient for gustier
southwest winds. Monday looking more likely for the combination
of these two for elevated to critical fire weather concerns.
Have opted to go straight to Red Flag Warning for southern WY
for Monday, as confidence in that period looks higher,
especially with humidity levels falling below 10 percent for an
extended period of the day. Tuesday is also looking very dry,
but winds currently forecast to hold back from Monday numbers,
so will not stretch the Red Flag beyond Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 940 PM MDT Sat Aug 2 2025

The main aviation weather concern overnight is isolated rain
showers that will continue into the early morning hours, which
is unusual for Wyoming. These could bring brief light rainfall
and gusty outflow winds. Most lightning has ended for the
evening, but a rogue lightning strike can`t be ruled out.

A drier air mass moves into the southwest half of the state
Sunday, but the Bighorn and Powder River Basins hold on to
moisture, and it`s in these places that isolated showers and
thunderstorms could develop during the afternoon. Have hinted
at VCSH for both KCOD and KCPR in the 06Z TAFs.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 8 PM MDT Monday for WYZ277>279-
288-289-414-416.

&&

$$

DISCUSSION...Straub
AVIATION...VandenBoogart