157
FXUS65 KRIW 100711
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
111 AM MDT Fri May 10 2024

.KEY MESSAGES...

- Showers and isolated storms ending later this afternoon.

- Most locations should have a mostly clear sky tonight for the
  possible appearance of the northern lights.

- Only isolated showers and storms with mild to warm
  temperatures this weekend.

- More active early next week with a better chance for showers
  and thunderstorms.

&&

.DISCUSSION...
Issued at 109 AM MDT Fri May 10 2024

It seems like some meteorologists have the worst luck. It was off
for three days earlier this week. And, as an avid golfer, I wanted
to go out and hit the links. Well, Monday through Wednesday was
way too windy to get out there. And now that I have to work, we
will have a few nice days to golf. Just my luck.

There will be one last shortwave rotating through the area today,
and this will bring another chance for showers and isolated
thunderstorms. The difference will be that coverage should be less,
only 2 out of 5 at best with the exception of the mountains. And,
showers should end from north to south through the day. Wind will
still be gusty in the south, but less so across the north. And then
it will clear from north to south through the day and and into the
night. And sky cover will be critical tonight.

The reason is, we have the potential for one of a really good
display of the northern lights tonight. Out colleagues at the Space
Weather Prediction Center have a watch for a G4 storm, the first
watch like this in 19 years. Space weather can be fickle but the
potential is definitely there. And, for most of the area the news
for sky cover is good as ridging builds across the area. The sky
should be mostly clear, especially across northern portions of the
area. It will be slower to clear across the south and west though,
But even here, clouds should then through the night. And, with the
expected maximum display expected after midnight, the sky should
continue to clear. Stay tuned for updates though. If you want
details, we will have a video on social media around 6 am this
morning.

The weekend for the most part looks very nice. Saturday looks like
the best day as ridging moves into the area. There will be just
enough instability for an isolated shower or thunderstorm roughly
from Interstate 80 and south, but even here the chance is less than
1 in 4. Most other locations will have a nice Spring day with mild
temperatures and light to moderate wind. Sunday looks a bit more
active as a weak shortwave brushes by to the east. This will
increase the coverage of diurnal convection. Most areas will again
have less than 1 in 4 chance of a shower or thunderstorm, but the
chance will be a bit higher in Natrona and Johnson Counties. But
even in areas that get one, a vast majority of the day will be dry.

Things then turn more active for the first part of next week as a
couple of cold front and troughs move across the state. The first
moves through Monday and brings a more widespread chance of showers
and thunderstorms to the area, with decent model consensus for the
northern half of the state to see the greater coverage. The timing
of the second is more uncertain, with a 12 to 24 hour spread in
guidance. For now, we went with mainly chance POPS and tried not to
pinpoint an area this far out. Temperatures will warm ahead of the
front, with some locations in the 80s before cooling for Tuesday and
Wednesday. The late week shows ridging building in with drier
conditions and warm temperatures returning.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1039 PM MDT Thu May 9 2024

West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals

Prevailing VFR conditions through the TAF period as the persistent
weather system begins to exit the area. Isolated showers are
possible at KRKS through Friday afternoon, but too low of a chance
(20%) for a prevailing -SHRA group. Wind will remain strong at KRKS
through Friday afternoon from the northeast, with gusts to 30 knots
by 12Z. At KJAC the predominant wind direction will be northerly
right around 10 knots through the TAF period. Scattered mountain
obscuration will occur.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals

The persistent weather system continues to influence the weather
conditions through Friday afternoon, but it will slowly exit the
area leading to lesser impacts on Friday. An area of -SHRA is
approaching KLND and should impact the terminal until 08Z, with a
lowering in clouds to MVFR once it passes. Isolated -SHRA remain
possible (30%) at KLND through Friday morning. Improvement to VFR
will occur by Friday afternoon as CIGS rise. Isolated -SHRA remain
in the vicinity of KCPR tonight and become more scattered by 10Z/Fri
as CIGS drop to IFR until 15Z/Fri. By that time improvement to VFR
will occur. Other terminals will remain mostly dry and VFR, although
an isolated -SHRA is possible (20%) through Friday afternoon. Wind
will become light tonight, mainly from the north/northeast. Mountain
obscuration will persist along the eastern slopes of mountain ranges
as easterly upslope flow persists through Friday afternoon.

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...Rowe