942
FXUS65 KRIW 071746
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
Issued by National Weather Service Billings MT
1146 AM MDT Wed May 7 2025

.KEY MESSAGES...

- Drier today with near normal temperatures and only isolated
  showers.

- Warmer Thursday and Friday with a scattering of showers and
  thunderstorms.

- The warmest weather of the year possible this weekend, with
  warmer locations making a run at highs around 90.

&&

.DISCUSSION...
Issued at 302 AM MDT Wed May 7 2025

After the wintry weather of the past couple of days, spring
will continue it`s swing of the pendulum, this time into Spring
and possibly a bit of summer. Things are largely quiet right
now, with radar only showing a few sprinkles in Natrona County.
We still have cloud cover hanging around the area, although this
will slowly part for increasing amounts of sunshine as the
upper level low over the central Plains states moves away. So,
today looks like a seasonable dry for the area. There is just
enough moisture and instability around for a few showers in the
area, but most locations will not see one.

Things will turn a bit more active for Thursday and Friday. A
shortwave will track across the area on Thursday and bring some
scattered showers and thunderstorms, with an emphasis on
northern and western portions of the area which will have better
forcing. Even here, the chance of any location seeing one is
only around 1 out of 3 and most of the day will remain dry. The
big change will be temperatures as flow turns to southwest and
pushes temperatures to above normal levels, averaging about 10
degrees above normal with a decent chance of highs in the 80s in
the normally warmer locations. Another shortwave moves in for
Friday with another chance of showers and storms. On this day,
most models agree with the best coverage across eastern portions
of the area with tapering chances further west. Temperatures
should be similar to Thursday.

Saturday looks like a dry and warm day at this point. A
approaching trough for Sunday will bring the chance of showers
and thunderstorms, so the weekend looks like a 50 - 50 type.
Temperatures this weekend will likely be the highest so far this
calendar year. Some of the warmer locations, like Worland and
Greybull, could make a run at 90 degrees for a high, especially
on Sunday when increasing wind ahead of the trough may enhance
mixing. If it happens at Greybull, it could tie the earliest 90
degree high in station history.

Early next week, a lot depends on what happens with an upper
level low that will be moving onshore in the Pacific northwest.
There is a lack of agreement in regards to the progression of
this system. It has the potential to bring a decent rain or even
strong thunderstorms depending on the scenario. My gut feeling
is that it will be slower, since the models usually have a fast
bias this far out. However, details on timing and placement of
precipitation are anyones guess at this point.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1144 AM MDT Wed May 7 2025

MVFR cigs linger at KBPI, KCPR, KLND, and KRIW to start the period,
but should scatter out by 19Z to 20Z, with KCPR holding onto those
low clouds the longest. After the low clouds scatter out, all sites
will prevail VFR through the period with mostly clear skies. Light
winds also generally prevail through the period. KCOD and KWRL will
be the only exceptions with gusts 20kts through the period.

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...Hattings
AVIATION...Hensley