817
FXUS65 KRIW 200423
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1023 PM MDT Sat Apr 19 2025

.KEY MESSAGES...

- A quick-moving weather system will bring light snow to the
  western mountains and the Bighorns late tonight through
  Sunday. Lower elevations will quickly see any snow showers
  change to rain after sunrise Sunday.

- Light mountain snow and lower elevation rain become more
  widespread Sunday night through Monday. Travel impacts are
  expected to be limited to mountain passes.

- Gusty west winds are expected Monday afternoon.

- The upcoming week will remain active with multiple chances for
  light precipitation while temperatures gradually warm back to
  seasonal normals.

&&

.UPDATE...
Issued at 131 PM MDT Sat Apr 19 2025

Satellite imagery early this afternoon shows clear skies and a
fresh snowpack for many areas, albeit a snowpack that is already
shrinking with warming temperatures and a harsh April sun
angle. The next system is on track to push into western Wyoming
tonight. There has been little change with snowfall amounts with
this update for Sunday, generally only up to a few inches on
the higher terrain of northern and western Wyoming. Light rain
will accompany this across the lower terrain of these areas in
the morning.

After this initial disturbance moves out, weak instability will
develop in the afternoon as the main trough approaches, leading
to additional isolated showers and possibly a thunderstorm or
two across the northern half of the area. The trough axis will
pass from west to east Sunday night. One change with this
feature is that forecast snow accumulation across the western
mountains has increased slightly, though still generally less
than 6 inches for most locations. Impacts should remain minor,
mainly limited to mountain passes through Monday morning.

&&

.DISCUSSION...
Issued at 146 AM MDT Sat Apr 19 2025

Clear skies and recent snowpack has created favorable conditions for
chilly temperatures to return to much of the Cowboy State this
morning. Forecasted temperatures this morning are well below normal
ranging from the low to upper teens, with some isolated locations
even nearing the single digits. Fortunately, temperatures begin to
rebound today with highs for most warming back up into the 40s and
the northern half of the CWA possibly seeing 50s. Lingering snowpack
will melt throughout the day as skies remain mostly clear with
plenty of warm April sunshine. Clouds do begin to move into western
WY by the evening and gradually spread east Saturday night. This is
apart of a weak disturbance that is expected to near the region by
Sunday with showers moving into the state early Sunday morning.
Showers look to start across western WY and gradually spread
eastward through the morning and afternoon. Precipitation is
expected to be mostly scattered in nature with the best chances (30-
60%) across western and northern WY. However, it should not be a
washout with little moisture being associated with this disturbance,
so any holiday plans will likely not be in jeopardy. Temperatures on
Sunday will return to seasonable values ranging in the low 50s for
most.

The start of next week will see active weather continue across the
region with multiple chances for precipitation. Starting Monday a
shortwave looks to move into the area bringing with it chances for
snow/rain showers. The bulk of the energy associated with this
system is currently forecast to remain north of the state. If this
were to occur impacts will be mainly limited to the western and
northern portions of the CWA. Overall, impacts are expected to be
minor with 1 to 3 inches of wet snow across western mountains and
portions of the Bighorns. Elsewhere, showers will be scattered in
nature with temperatures keeping things in the form of rain across
lower elevations on Monday.

The remainder of the week as mentioned earlier, will be active with
chances for light precipitation. Temperatures are forecast to
continue to gradually warm with highs returning to the upper 50s and
low 60s by Wednesday. As of Saturday morning there does not look to
be any large or impactful system on the horizon as we saw this past
Thursday/Friday. However, if this active jet pattern does continue
it will only be a matter of time before we may see another potent
disturbance develop.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1020 PM MDT Sat Apr 19 2025

A weak weather system will bring mid level cloud cover and
mountain snow showers early Sunday morning. Most basins and
valleys remain dry, but a few hours of scattered rain showers
are possible for JAC, COD, and CPR as the system passes. Winds
remain light on Sunday, with skies partially clearing during
the afternoon and evening. The next weather system moves into
western Wyoming late Sunday evening into Monday morning,
bringing more widespread precipitation.

&&

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

&&

$$

UPDATE...Myers
DISCUSSION...Dziewaltowski
AVIATION...VandenBoogart