Riverton, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

137
FXUS65 KRIW 260409
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1009 PM MDT Sat Jul 25 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms continue this evening and
  will subside after sunset. A few thunderstorms could be
  strong, with locally gusty winds around 50 mph, mainly over
  the northwest- quadrant of the state.

- More scattered showers and storms will develop across the area
  Sunday afternoon. Again, locally gusty wind around 50 mph will
  be possible.

- Areas away from showers and thunderstorms will be hot Sunday,
  with highs in the 90s and low 100s. Heat Advisories are in
  effect for the basins of central and northern Wyoming Sunday.

- Above normal temperatures continue through the upcoming week,
  with highs each afternoon in the 90s. Monsoon moisture remains
  in place, producing afternoon and evening showers and
  thunderstorms through at least Wednesday.

&&

.UPDATE...
Issued at 1151 AM MDT Sat Jul 25 2026

Morning showers associated with a passing shortwave are about to
exit Johnson County late Saturday morning, while cumulus development
is already underway over southwest Wyoming. Despite a deep-mixed
layer and wide temperature-dewpoint spreads Saturday afternoon,
there is still plenty of mid-level moisture in southwest flow
aloft to generate scattered showers and thunderstorms. The
inverted-V profiles lead to the main hazard being gusty outflow
wind 40 to 50 mph from even weak convection. Most convection
wanes between 7 and 9 PM Saturday, although recent CAMS runs
show lingering weak convection over central Wyoming through
Saturday evening. Over far northwest Wyoming, a favorable plume
of mid-level moisture lingers until early Sunday morning leading
to isolated light showers. This same area receives another
punch of moisture late Sunday morning leading to earlier
convective development during the midday hours across this
region. A Heat Advisory continues through Sunday for basins east
of the Continental Divide as temperatures hover 8 to 12 degrees
above normal. The heat and associated low relative humidity
leads to elevated fire weather conditions Saturday afternoon,
especially in Natrona and Johnson Counties.

&&

.DISCUSSION...
Issued at 307 AM MDT Sat Jul 25 2026

Not much pattern change expected during the next week, as the H5
ridge remains firmly anchored on the Four Corners. This will
keep very warm temperatures in place across most of the state,
with highs each afternoon in the 90s. Today will be the warmest
of these days, with some 100 degree readings for the Bighorn
Basin and along the I-25 corridor.

Even with the ridge holding hot temperatures in place, the
placement of the ridge will still allow monsoon moisture to draw
northeast into the western half of the state. This will bring
daily chances for showers and thunderstorms building along
the higher elevations of the western mountain ranges, then
drifting northeast around the ridge into Montana. Shower chances
will be enhanced by any small-scale shortwaves wrapping around
the ridge. One of these will sweep through this afternoon across
NW Wyoming. Combine this enhancement with higher temperatures
today to bring some strong thunderstorms. With dewpoint
depressions approaching 50 degrees, very gusty winds would be
the main impact, with wind gusts in excess of 50 mph possible.
As these storms are moving northeast at a reasonable rate,
localized flooding concerns are decreased today. Daytime
thunderstorm chances will continue through the week, building
during the afternoon before decreasing at sunset.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1000 PM MDT Sat Jul 25 2026

Enough mid-level moisture remains overnight to allow for
continued isolated showers over the northwest-quadrant of the
state into early Sunday morning. Convection will develop over
the western mountains after 18Z, quickly becoming widespread by
20Z/21Z and pushing east into the central basins. PROB30 groups
have been added to KBPI/KPNA and KRIW/KLND and KWRL as a
result, with KJAC and KCOD still under threat from these
afternoon showers and thunderstorms. Gusty outflow wind 35-45kt
will again be the primary hazard. Confidence remains too low to
include a PROB30 group at KRKS at this time, but could be added
in a future forecast.

Showers and thunderstorms will be ending/moving east out of the
forecast area after 00Z Monday through sunset. Model trends are
depicting scattered showers moving northward over southern
portions after 03Z Monday.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM MDT Sunday for WYZ003>006-010-011-017-
018-020.

&&

$$

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