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000
FXUS65 KRIW 240908
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
308 AM MDT Wed Apr 24 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms are again expected today,
  mainly for the higher elevations of western and Central
  Wyoming.

- Showers and thunderstorms are likely across all of western and
  central Wyoming during the day Thursday, including most higher
  elevations.

- More potent weather system moves through late Friday and
  continues through the weekend, with widespread rain and snow.

&&

.DISCUSSION...
Issued at 232 AM MDT Wed Apr 24 2024

More active pattern continues to evolve across the state today
along and ahead of the next weather system. This midlevel trough
will be moving ashore this afternoon along the southern
California Coast, with instability and deeper moisture ahead of
it. Still, with the distance from the approaching trough, shower
activity will be widely scattered, with the best focus on the
western mountains ranges, stretching east along the Greens and
toward Casper Mountain. Precipitation accumulation will still
be low, as the sfc moisture levels remain dry. The dry air may
help any showers produce locally gusty winds.

Thursday the trough will be lifting northeast across the Four
Corners in to Colorado. With the system closer to WY, more
widespread moisture will be available for scattered to numerous
showers and thunderstorms. Most precip will again focus on
higher elevations, with warmer temperatures likely keeping all
precip as rain. As this first trough moves into western Nebraska
and wrap up, wraparound northeasterly flow will bring improved
orographic and isentropic lifting across the western half of the
state. This trough is quickly followed by a second trailing
trough on Saturday. The best focus for light to moderate rain
would be long the eastern slope of the Winds and the Absarokas
later Friday through Saturday. Probabilities for 1" of rainfall
remain 40 to 50% for the Wind River Basin, around 30% for
Casper, and generally around 10 percent for the remainder of the
lower elevations. The wraparound flow with the second trough
will bring colder temperatures aloft, which will bring snow
levels downward near 8000 feet. In the preferred regions of the
eastern facing Winds and Absarokas, chances of receiving 10
inches of snowfall remain above 70%.

Models note that after this trough moves to the northeast,
midlevel flow will remain from the west and southwest off the
Pacific into next week, which will keep the moisture flowing
into the western mountains, with light precipitation continuing
into the extended period.


&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 952 PM MDT Tue Apr 23 2024

VFR conditions are expected to prevail through the period. The gusty
wind at KCPR will decrease over the next couple of hours, with wind
generally remaining light at terminals through Wednesday morning. A
weak shortwave and increasing moisture will allow for some isolated
convection Wednesday afternoon and evening. We have introduced some
prob30 groups to account for this, with the best chances for
terminal impacts at KBPI, KPNA, KJAC, and KCPR. Given drier air at
the surface, strong gusty winds will be the main concern with this
activity.

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...Straub
AVIATION...Myers