512
FXUS65 KRIW 270904
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
304 AM MDT Mon Jul 27 2026

.KEY MESSAGES...

- Increased cloud cover will keep temperatures down a few
  degrees from yesterday`s record high temperatures. Afternoon
  highs will still reach the 90s across the state.

- Scattered showers and thunderstorms will again develop early
  this afternoon and move to the northeast during the day.
  Monsoon moisture will be on the increase this morning, leading
  to better chances for thunderstorms than previous days.

- This pattern remains in place through the week, with above
  normal temperatures in the 90s and thunderstorms developing
  each afternoon.

&&

.DISCUSSION...
Issued at 231 AM MDT Mon Jul 27 2026

The dominant western ridging pattern holds firm again today, the
the H5 ridge still anchored on the Four Corners region. The
southwest tap of monsoon moisture continues today, and most
models are bringing an increase in moisture during the next 6 to
12 hours. With warm temperatures still in place, daytime showers
and thunderstorms will again develop late this morning and
continue into the afternoon, moving to the northeast. The
increased moisture and shortwave energy passing through today
will bring a better chance for measurable rainfall from any
thunderstorms, but the good forward motion of any storms will
keep the chance for flooding low. Current cloud cover and any
cover from thunderstorms today will keep temperatures lower
than Sunday. Highs will still be above normal, but will hold in
the low to mid 90s through the afternoon.

Tuesday will be similar to today, with very warm temperatures
during the day. Ample moisture will tap this heat for scattered
showers and thunderstorms during the afternoon. Midlevel support
may be more limited, so showers might end up more isolated.

Wednesday another more vigorous shortwave comes around the ridge
through Wyoming, which is expected to bring a much better chance
for showers and thunderstorms. After this feature passes
through, models are shifting the ridge slightly to the west
through the rest of the week into the upcoming weekend. Models
are noting a significant drop in moisture, as the monsoon
moisture gets cut off. This would lead to much drier and warmer
period heading into the weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1015 PM MDT Sun Jul 26 2026

Chances for light, weak showers will continue over southern
portions of the forecast area to start the TAF period, as a
moist, southwest flow brings another moisture surge northward
through the rest of the night. These showers will spread
northward over the western mountains between 10Z and 13Z. Gusty
outflow wind around 35kt will be possible through the rest of
the morning with these showers. This moisture then serves as
the fuel for another round of diurnal convection beginning
around mid- afternoon Monday. Many terminals see wind less than
10kt, outside of convection, until late Monday afternoon when
convective outflows occur.

The showers over the western mountains will spread east into the
central basins and other points east of the Divide late in the
morning into early afternoon. Additional thunderstorms look to
develop over the Upper Green River Basin and southern portions
after 21Z and move toward the northeast into the evening. Will
keep the current PROB30 groups that are already in place, as
widespread convection is still expected during the afternoon.
This may change depending on how the morning showers impact the
afternoon convection.

Please see the Aviation Weather Center and/or CWSU ZLC and ZDV for
the latest information on smoke, icing, and turbulence
forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Straub
AVIATION...CNJ/LaVoie