Mills, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

364
FXUS65 KRIW 070453
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
953 PM MST Fri Mar 6 2026

.KEY MESSAGES...

- Skies slowly clear overnight, with a slight chance for patchy
  fog (20% chance), especially in valleys west of the
  Continental Divide that received snow today.

- Gusty winds are expected for most locations on Saturday, with light
  snow chances across the Tetons and Yellowstone National Park.

- Warmer temperatures and widespread strong winds are expected through
  much of the upcoming week. This will lead to periods of
  elevated to critical fire weather conditions.

&&

.UPDATE...
Issued at 131 PM MST Fri Mar 6 2026

The last stand of the current system is ongoing early this afternoon
with areas of lighter snow mainly east of the Divide. Additional
snow showers are expected to develop through the afternoon given the
weak instability behind the cold front; this activity will be fairly
isolated with the best chances over the western mountains. We will
allow the remaining Winter Weather Advisories to continue for now
given that current radar and webcam imagery is still showing
snowfall and areas of limited visibility. Snow will taper off this
evening and end everywhere by midnight with skies clearing
overnight.

&&

.DISCUSSION...
Issued at 105 AM MST Fri Mar 6 2026

Light snow continues across much of the area early this morning, as
the main trough of this storm system moves over the region. The
associated upper low is not as discernible on satellite, but remnant
circulations look to be reorganizing over southwestern portions of
the state. Northerly flow will remain in place in the wake of the
cold front, which crossed the Divide around 06Z. Locations that are
prone to northerly winds will have the higher snowfall amounts this
morning (which will not be much) such as, the Owl Creek/Bridger
Mountains, the east slopes of the Wind River Mountains (specifically
near Sinks Canyon and Red Canyon/South Pass), and the north face of
Casper Mountain. Additional snow showers will develop off the
mountains this afternoon, as northerly flow aloft becomes stronger
due to a strong ridge building in from the west. There will be
enough instability for these showers to form, however, the main
impact will be visibility as accumulations will be limited to up to
an inch. Locations like waltman/Hiland in Natrona County and South
Pass will be impacted by these showers, as well as across Interstate
80 and US-191 south of Rock Springs toward Flaming Gorge. Northerly
winds with gusts of 25 to 35 mph will continue through the day
across areas east of the Divide and the eastern half of Sweetwater
County. Temperatures will be more seasonal today, ranging from the
upper 30s into the 40s for much of the area. The snow showers and
wind will end early in the evening, as drier air makes its way into
the area behind the exiting storm.

Northwest flow aloft will be in place Saturday, as the
aforementioned strong ridge over the EPAC begins to fold over the
PACNW. While conditions will remain dry, west wind gusts of 25 to 35
mph will return across southern portions and the Wind Corridor (Rock
Springs to southern Johnson County). Slightly higher wind gusts up
to 45 mph will occur near Cody and the Upper Wind River Basin. The
latter winds could reach the Riverton area late in the afternoon.
Above normal temperatures will return as a result of these winds,
especially east of the Divide.

The ridge begins to flatten Sunday, as the PFJ strengthens to a
150kt jet max and makes its way over southern British Columbia. The
right front quadrant of the jet will be over far northwestern
portions during the day, which could result in high winds. A High
Wind Watch may be needed for the Cody Foothills, as the NAM shows a
strong downsloping signature developing between 09Z and 12Z Sunday.
This is marked by a tight 700mb temperature gradient along the east
slopes of the Absaroka and Wind River Mountains, ranging from 5C to
minus 6C over the mountains. The Upper Wind River Basin zone
(impacting Dubois and Crowheart) could be impacted as well. Will let
the day shift take a look and possibly issue when the current
Winter Weather Advisories expire. Otherwise, similar conditions
from Saturday will return Sunday. Gusty west to northwest winds
will return to much of the same areas with above normal
temperatures. Areas east of the Divide will be in the 60s, with
a few locations in Johnson County approaching 70F.

Winds are not expected to be as strong over the Cody Foothills and
Upper Wind River Basin Monday (but gusty winds will continue to be
widespread), as a cold front approaches northern portions of the
state from MT. A more zonal flow pattern will be in place by this
time with the PFJ extending from the PACNW to the Great Lakes,
putting it over the northern half of the Cowboy State. Light snow
will be possible over northwestern portions due to orographic flow
and limited Pacific moisture, but accumulations look to be minor at
this time. Temperatures will continue to be well above normal for
early March. Light snow will be possible Monday night into Tuesday,
as the cold front makes its way southward. The front looks to become
stationary along the Owl Creek/Bridger Mountains and southern
Johnson County around midday Tuesday, keeping northern portions
having the best chances for light snow. Temperatures will remain
near seasonal levels as a result of the front, while central and
southern portions remain above normal. The PFJ will be further
south, with the stronger winds occurring over central and southern
portions. West to northwest winds, with gusts of 35 to 45 mph look
to be widespread over these areas. Additionally, elevated to
critical fire weather conditions will also coincide with these
areas, as RH values look to drop below 20 percent. Depending on how
much snow falls this morning (although it is not looking promising),
Red Flag Warnings may be needed for the Wind River Basin and Natrona
County (at least).

Warmer conditions return Wednesday, as a ridge quickly rebuilds over
the Great Basin. Windy conditions look to return as well. This trend
of widespread windy conditions, and possibly high winds in more wind
prone locations, look to continue through the rest of the week.
Another strong cold front impacts northern portions of the CWA
Friday, possibly reaching the Divide Friday night and retreating
northward again during the day Saturday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 951 PM MST Fri Mar 6 2026

VFR conditions are generally expected over the next 24 hours.

There is a small chance (20%) for patchy valley/basin bottom
fog around sunrise, especially for valleys west of the
Continental Divide, but given strong winds in the middle
atmosphere, the chance of this fog being dense or widespread is
low, despite precipitation earlier today.

Breezy winds of 20 to 25 kt are expected at several sites
Saturday afternoon, then winds increase in the middle atmosphere
during the evening and overnight into Sunday. Typical windy
spots like COD and CPR could see these gusts mix down to the
surface at times early Sunday morning.

&&

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

&&

$$

UPDATE...Myers
DISCUSSION...LaVoie
AVIATION...VandenBoogart