586
FXUS65 KRIW 310640
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1240 AM MDT Sun May 31 2026

.KEY MESSAGES...

- A weather system moving through the region tonight keeps it
  cool and mostly cloudy conditions.

- Tonight`s precipitation will be focused over the mountains and
  western valleys, but basins in central and northern Wyoming
  will see hit- or- miss scattered showers as well.

- Accumulating snow is likely in the higher elevation mountains
  tonight through Sunday, mainly above 10000 to 11000 feet.

- After the current weather system exits Sunday night, dry
  conditions prevail with temperatures gradually warming up over
  the first half of the work week.

&&

.DISCUSSION...
Issued at 1235 AM MDT Sun May 31 2026

As expected, areas west of a Cody-to-Rock Springs line had the
highest amounts of precipitation since 7am Saturday ranging between
0.15" to 0.70". Roughly add another 0.20" to include the
precipitation that was occurring earlier Saturday morning/Friday
night. Showers will be mainly confined to western and northern
portions of the CWA early this morning as the upper low continues to
slowly track toward the northeast. An area of showers will continue
over southern portions of the Jackson Valley/northern portions of
Star Valley and into the Upper Green River Basin, with additional
showers from southern MT moving over YNP and the rest of the Jackson
Valley around 10Z this morning. Showers and thunderstorms developed
over far northern portions of Johnson County around 05Z and have
been backbuilding toward Kaycee through 06Z. This activity will
continue to track westward over the Bighorns through 12Z this
morning.

Showers will become concentrated over northern portions after
sunrise this morning as the upper low moves over the Black Hills and
pivots over far eastern MT through the day. Any showers over the
Wind River Basin and Natrona County will be isolated and conditions
will remain dry elsewhere in the CWA. Precipitation amounts will be
much lower with these showers, ranging between 0.10" and 0.20"
through the day. Snow levels will stay around 9000-10000ft, with
lower levels around 7500 over YNP and the Absarokas. A brief heavy
downpour cannot be ruled out, especially in the Bighorn Basin, but
is not expected. Precipitation will end from west to east through
the evening. Otherwise, wind will be the main feature today with
gusts of 25 to 35 mph developing over areas west of the Divide after
15Z and spread into Natrona County by 18Z. Similar winds will
develop near Dubois and Crowheart after sunrise and spread down the
basin toward Riverton. These winds will decrease across the area in
the evening, lingering the longest in the Wind River Basin (which
should finally end around 07Z Monday).

Isolated showers and thunderstorms will be possible Monday, as a
shortwave moves over the Cowboy State. Winds aloft will be
southwesterly as a trough develops over the Northern Rockies from
the remnants of the upper low. Most of the convection looks to be
isolated across the CWA, occurring along and east of a line from the
Bighorns to western Sweetwater County. An additional area of
isolated showers will be possible over far northwestern portions.
Wind gusts up to 45 mph will be the main threat, as instability will
be pretty modest between 200-500 J/kg. Tuesday and Wednesday look to
stay mainly dry, with west-southwest winds aloft keeping any
potential convection over far eastern portions of the state. Showers
and thunderstorms will be possible again Thursday, with dry
conditions returning for Friday. Temperatures will be above normal
from Tuesday to Friday, with highs in the upper 70s into the 80s.
Hot and dry conditions look to return for next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1024 PM MDT Sat May 30 2026

The center of the weather system is passing through central Wyoming
currently. As it slides northeast tonight into Sunday, rain and
isolated thunderstorms will continue, mainly for KJAC, KCOD,
and KWRL. Conditions will drop to MVFR/IFR at KJAC tonight and
at other terminals impacted by heavier showers and storms.
Precipitation chances end for remaining terminals Sunday
evening, with KWRL being the last impacted before the weather
system moves out of the area.

Wind will increase Sunday morning at most terminals with 10-20 knots
and gusts of 20-30 knots through Sunday afternoon. Stronger wind
will occur at KRKS, with gusts up to 40 knots possible Sunday
afternoon. Wind will decrease substantially by 02Z-03Z Monday
across the area. Frequent mountain obscuration continues across
western and northern portions of the area through Sunday
morning, with improving conditions Sunday afternoon into Sunday
evening.

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...
None.

&&

$$

DISCUSSION...LaVoie
AVIATION...LaVoie/Rowe