600
FXUS65 KRIW 012206
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
406 PM MDT Wed May 1 2024

.KEY MESSAGES...

- Afternoon scattered showers and weak thunderstorms are in the
  forecast daily through Friday. Light mountain snow
  accumulations are also possible over the next 48 hours.

- Elevated fire weather conditions exist this afternoon for
  Sweetwater and Natrona counties, due to a combination of
  breezy winds and a dry air mass.

- This weekend will be warm and dry east of the Divide, with
  cooler and wetter conditions for western Wyoming mountains and
  valleys.

&&

.DISCUSSION...
Issued at 250 PM MDT Wed May 1 2024

A longwave trough resides over the Intermountain West this
afternoon, with an approaching embedded shortwave. The cool air
aloft will encourage scattered shower development, but
accumulations from the short-lived showers will be minimal. This
afternoon and evening will also feature breezy winds in the
Sweetwater to Natrona county wind corridor as the shortwave
trough tightens the surface pressure gradient. When combined
with the relatively dry air mass, elevated fire weather
conditions will exist through sunset.

Thursday and Friday feature much of the same weather, with
temperatures about 5 degrees below seasonal averages, and
scattered afternoon showers. Accumulations will again be minimal
for lower elevations. Winds will be lighter these days, so fire
weather concerns are not as high.

On Saturday, a brief ridge moves through the Rockies, leading to
a quick warm up to about 10 degrees above seasonal normals. No
precipitation is expected, and winds are not overly breezy,
making conditions favorable for many outdoor spring activities.

On Sunday, a deep trough begins to push into the western Wyoming
mountains. This will bring a return of showers for locations
west of the Divide, but those in the basins east of the Divide
will enjoy a very mild day, with temperatures 15 or so degrees
above average.

On Sunday night into Monday, the weather system associated with
this trough will move across the state, bringing a noticable
cooldown, as well as more numerous showers and measurable
precipitation for many. Western Wyoming valleys could see light
snow during the overnight timeframe, but this would likely melt
quickly after sunrise Monday given high temperatures in the
40s. In the wake of this system, conditions moderate to near
seasonal averages by mid-week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 342 PM MDT Wed May 1 2024

The best chances for precipitation should be coming to an end the
first few hours of the TAF period, mainly for northern Wyoming
sites. There is about a 15% chance for showers impacting KCPR, KLND,
and KRIW through about 06Z, slightly longer at KCPR. Winds also
decrease after sunset for most locations, with gusty winds ending by
around 05Z. A northwest drainage wind is possible longer at KRIW.
Winds then increase again Thursday, with gusts generally 20 to 30
knots for many sites. Showers are again possible for the afternoon,
occurring in similar locations to what occurred Wednesday.

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...VandenBoogart
AVIATION...Lowe