Riverton, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

330
FXUS65 KRIW 302152
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
352 PM MDT Sun Mar 30 2025

.KEY MESSAGES...

- A rain snow mix continues across portions of central Wyoming
  this afternoon ending quickly this evening. 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 1-3
  inches until 6 PM MDT.

- Showers and isolated thunderstorms are likely (70-80%) 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 205 PM MDT Sun Mar 30 2025

The low continues 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 Mountains and Absaroka Mountains this
afternoon. 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 has melted as
the snow pushes northeast out of the area this afternoon and
skies clear a bit. Extended the Winter Weather Advisory for the
Absaroka Mountains until 6 PM this evening as convective snow
showers have developed this afternoon and will 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 expired 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. All snow showers will end this
evening, but the next system approaches from the west tonight
and brings snow chances back into western Wyoming after
Midnight.

&&

.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 /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 351 PM MDT Sun Mar 30 2025

The latest shortwave will continue to exit the region. Overall,
conditions will gradually improve across east of the Divide
terminals through the afternoon and evening with prevailing VFR for
most terminals after 06Z Monday.

Hi-res models continue to indicate that there will be some initial
convection overnight tonight ahead of the next shortwave. 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.

The next shortwave will move into the region Monday morning, with
west of the Divide terminals starting to see MVFR/IFR impacts after
sunrise. Any precipitation Monday will be showery in nature and thus
it is hard to pinpoint exact timing and locations. Due to the low
confidence, have mostly left shower mentions for Monday afternoon
out of the TAFs for now. Westerly winds will increase at several
terminals Monday afternoon as well, with gusts to 20kts possible at
KCOD, KCPR, and KRKS.

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 6 PM MDT this evening for WYZ002-
009.

&&

$$

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