Mills, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

217
FXUS65 KRIW 301732
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1132 AM MDT Sun Mar 30 2025

.KEY MESSAGES...

- Precipitation will be widespread along and east of the
  Continental Divide this morning. Areas of snow continue this
  morning with a changeover to a rain snow mix this afternoon.
  Mountain areas will remain all snow.

- A Winter Weather Advisory remains in effect for the Bighorn
  Mountains and the Absarokas for additional snow amounts of
  1-4 inches.

- Showers and isolated thunderstorms will be possible for much
  of the forecast area Monday and Tuesday, with light snow
  overnight, especially western and northern portions.

- The active weather pattern continues through the middle of the
  week, but precipitation chances will decrease heading into the
  latter half of the week as high pressure settles in this
  upcoming weekend.

- Temperatures will remain cool through this week and begin to
  increase by next Sunday.

&&

.UPDATE...
Issued at 1053 AM MDT Sun Mar 30 2025

The low is sliding northeast through central Wyoming this morning,
which is right on track. An area of moderate snowfall developed on
the north side of this low and dropped a few inches of snow in the
Wind River Basin and continues to drop snow in the Bighorn Basin up
into the Absaroka Mountains this morning. Most locations only had
snow accumulate on elevated surfaces and in the grass, but there was
about an inch of slushy snow on roadways in some locations. This
slush will melt as the snow pushes northeast out of the area this
afternoon and skies clear a bit. Will be extending the Winter
Weather Advisory for the Absaroka Mountains until 6 PM this evening
as convective snow showers are likely (70%) to develop this
afternoon and result in a few more inches of snow along the eastern
slopes of the Absaroka Mountains. The Winter Weather Advisory for
the eastern slopes of the Wind River Mountains will be allowed to
expire at noon today as snow has all but ended there. The Winter
Weather Advisory for the Bighorns will remain in effect until 6 PM
this evening as another few inches of snow will fall there.

&&

.DISCUSSION...
Issued at 111 AM MDT Sun Mar 30 2025

Precipitation will continue (basically) along and east of the Divide
through the rest of the morning, which would be from Yellowstone to
the Wind River Mountains and far northern portions of Sweetwater
County. Snow will be ongoing over these areas through early in
the afternoon, although accumulations will be confined to grassy
areas after sunrise. Additional isolated showers will redevelop
across the forecast area, especially northwestern portions,
through the afternoon.

A ridge will build over the region tonight into Monday irt another
strong upper low off the PACNW coast. This will keep Pacific
moisture streaming over the region and troughs ejecting from this
system move over the CWA. Additional showers will reach far western
portions Monday morning, with another round of showers developing
over southern portions in the afternoon. Isolated thunderstorms
could occur in these areas through the afternoon. Isolated showers
and thunderstorms will also be possible east of the Divide, as the
shortwave trough moves eastward. This activity will continue through
the evening. Snow levels will average between 6000 and 7000ft across
most of the forecast area, but again any snow that falls during the
day will have little to no impact and accumulate in grassy areas.

The aforementioned shortwave trough will slow down Monday night and
become better organized into a midlevel low, dropping temperatures
and allow for rain to change over to snow over western portions.
This activity will continue through much of the day Tuesday, as the
low slowly moves over the Bighorn Basin and Johnson/Natrona
counties. As a result, most of the precipitation over northern
portions will occur under a developing baroclinic leaf from the
midlevel low. Rain/snow to snow will push into northern portions of
the Bighorn Basin and northern Johnson County Tuesday evening. This
activity will spread southward through the night as the low tracks
over the Black Hills.

Forecast details become less clear by Wednesday. Showers remain
possible for much of the area, but will be dependent on how much
influence from the exiting low/storm remains. Additionally, the
remnants from the PACNW low look to dive southward over the Four
Corners region, so forecast details are highly in flux through the
rest of the period. No clear signal for wet conditions to continue
or more drier conditions to occur.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1130 AM MDT Sun Mar 30 2025

The latest shortwave will continue to exit the region. Widespread
snow and low clouds continue to exist across east of the Divide
terminals, with KCPR, KCOD, and KWRL expected to hold onto IFR cigs
through the afternoon. Overall, however, conditions will gradually
improve across all terminals through the afternoon and evening with
prevailing VFR for most terminals after 06Z Monday.

The next shortwave will move into the region late in the period
however, with west of the Divide terminals starting to see MVFR/IFR
impacts after sunrise Monday morning. Any precipitation Monday will
be showery in nature and thus it is hard to pinpoint exact timing
and locations. Ahead of this next shortwave, Hi-res models do
indicate that there will be some initial convection overnight
tonight. Most likely impacts from this initial push of moisture
would be at KJAC (30% chance) and KBPI and KPNA (15-30% chances).
Occasional MVFR conditions are possible (20% chance) with these
showers.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon MDT today for WYZ002-015.

Winter Weather Advisory until 6 PM MDT this evening for WYZ009.

&&

$$

UPDATE...Rowe
DISCUSSION...LaVoie
AVIATION...Hensley