Mills, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

075
FXUS65 KRIW 160909
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
Issued by National Weather Service Billings MT
309 AM MDT Wed Jul 16 2025

.KEY MESSAGES...

- Isolated to scattered, mostly virga showers/dry thunderstorms
  are expected across southern Wyoming this afternoon. These
  virga showers/dry thunderstorms will be capable of around 40
  mph outflows.

- Below normal temperatures east of the Divide and near normal
  temperatures west of the Divide today. Elevated fire weather
  conditions exist today across southern Wyoming, especially the
  Green River Basin.

- Warmer temperatures return on Thursday through at least early
  next week. The greatest shower and thunderstorm chances exist
  Friday and Saturday afternoons.

&&

.DISCUSSION...

Issued at 309 AM MDT Wed Jul 16 2025

The upper-level trough that drove Tuesdays thunderstorms will
be over the Upper Great Plains by early afternoon, leaving
Wyoming in zonal flow aloft. At the surface, a frontal boundary
will remain stationary along the Divide. East of the Divide,
saturated northerly flow will keep temperatures much cooler than
what we have been experiencing the past week or so.
Temperatures here will be about 5 to 12 degrees cooler today (in
the 60s and 70s), which will be 10-20 degrees below normal for
mid-July.

West of the Divide, unsaturated westerly flow with mean 700-mb
temperatures will keep temperatures largely near normal today.
Deep mixing in conjunction with the already unsaturated westerly
flow, will help drop relative humidity values to around 15-20%
west of the Divide with the lowest values across the Green River
Basin. The surface pressure gradient will remain somewhat tight
west of the Divide, leading to west-northwest winds gusting 20
to 30 mph. Critical fire weather conditions will be marginal and
not widespread, as a result at this time, thus no highlights
are being issued. However, with the westerly winds being
funneled down the Green River Basin, relative humidity values
below 15% is not completely out of the question this afternoon.

An embedded disturbance aloft is forecast to trek across
southern Wyoming late this afternoon and evening and provide
support for isolated to scattered showers and thunderstorms
across Sweetwater County. With mean SBCAPE forecasted around 500
J/kg at its highest and 0-6km shear around 20kts, storms are
not expected to become severe. However, given the dry low-levels
with dewpoint depressions between 30-40 degrees a virga shower
or dry thunderstorm will be capable of producing gusty outflows
around 40 mph.

Ensemble model guidance is in consensus in zonal flow aloft and
weak unsaturated low-level flow on Thursday. This will begin
the first day of a warm up to near to above normal temperatures
across the entire area. By Friday afternoon, an upper-level low
develops over southern California and a trough begins developing
over the Pacific Northwest and this set-up ushers in increased
moisture into the Intermountain West. This increased moisture
aloft and a weak disturbance aloft will support afternoon
isolated to scattered showers and thunderstorms across southern
Wyoming and east of the Divide Friday afternoon. These scattered
shower and thunderstorm chances are expected again on Saturday
across southern Wyoming as another disturbance treks across the
area and a surface boundary situates itself near the southern
Wyoming border. Drier weather and near normal temperatures are
expected to return Sunday through early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1030 PM MDT Tue Jul 15 2025

Showers will linger across central Wyoming tonight, with some
impacts at KCPR and KCOD. Low clouds will continue at KCOD and
KCPR with IFR conditions through Wednesday morning, improving to
VFR Wednesday afternoon. Showers will end early Wednesday
morning with more scattered showers and storms near KRKS
Wednesday afternoon, with a PROB30 to cover this threat. Wind
will be gusty at many terminals Wednesday afternoon.

&&

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

&&

$$

DISCUSSION...Gerhardt
AVIATION...NWS Riverton