Lander, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

772
FXUS65 KRIW 260002
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
602 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 /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 425 PM MDT Sat Jul 25 2026

Ongoing convection, mainly across the north-half of the forecast
area, decreases in coverage and intensity between 01Z-03Z/Sunday. A
dry sub-cloud layer with wide temperature-dewpoint spreads will
continue to favor gusty outflow wind 35-45kt. Lingering 15-20kt
surface wind gusts fizzle around 02Z/Sunday before returning to
KCPR late Sunday morning, and at KPNA and KBPI early Sunday
afternoon.

Enough mid-level moisture remains overnight to allow for
continued isolated showers over the northwest-quadrant of the
state into early Sunday morning. This region, including, KJAC
and KCOD, is where showers and possibly even a thunderstorm,
will begin to develop late Sunday morning. By early afternoon,
convection that initially develops over the higher terrain will
begin to move east into the basins. PROB30 groups have been
included at terminals where confidence is high enough for
potential impacts after 20Z-21Z/Sunday. Gusty outflow wind
35-45kt will again be the primary hazard.

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...CNJ/LaVoie