251
FXUS65 KRIW 101119
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
519 AM MDT Thu Oct 10 2024

.KEY MESSAGES...

- Another day like yesterday with well above normal temperatures
  and light to moderate wind.

- A cold front will bring more clouds tonight, and may prevent
  the viewing of a possible impressive display of the northern
  lights.

- Somewhat cooler but dry weather then dominates from Friday
  through at least the middle of next week.

&&

.DISCUSSION...
Issued at 118 AM MDT Thu Oct 10 2024

All in all, it looks like generally more of the same over the next
several days. Today will be another warm dry with a light to
moderate wind. And, has been over the past several days, those
persistent areas of smoke. There could be a few more clouds through,
especially in the afternoon as a shortwave and weak cold front
approach the area. And this will have an unfortunate impact, but not
the one you may be thinking of.

Shifting to space weather for a minute, there was another large
coronal mass ejection from the sun, and it will arrive sometime
today. There is a G4 watch out from today through tonight and even
into tomorrow. For reference, G4 is as high as the watches go, there
is no G5 watch. And there has been some talk from our colleagues at
the Space Weather Prediction Center of possible G5 conditions, which
would lead to an display of the aurora like the one back in May.
Space weather is fickle though so no guarantee, but the chances look
good. And back to terrestrial weather, here is the problem. The front
and wave will move across the state tonight. As for showers, there
is little low level moisture so anything would be light and
restricted to northern Wyoming, but even here the chance is only
around 10 percent so we kept the forecast dry. The problem is the
sky cover. Most of the area will have a mostly cloudy sky with a mid
level cloud deck much of the night. It does not look like a total
overcast though, so there should be some breaks. At this point, the
best conditions would be across southern Wyoming. But a clear sky
looks very unlikely at this point. The front will also brings some
gusty breezes to areas like the northern Big Horn Basin and Johnson
County, but high wind is not expected at this time.

Dry weather should then hold early next week as ridging builds back
into the area. High temperatures will be knocked down a few degrees,
but will still average 5 to 10 degrees above average through the
period. An upper level low will try to move toward the area for
Monday or Tuesday but now looks to be shunted south and looks to
have little effect on the weather at this point. There is some hope
for precipitation toward the end of next week as a Pacific front
approaches the area. This is still at least 7 days away and we have
seen to many of these not come to fruition so confidence is low. The
forecast probably is the fastest it would reach the area, Wednesday
night. Given the fast bias of the models this far out, it would more
than likely be next Thursday or even Friday before we see any
impacts.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 515 AM MDT Thu Oct 10 2024

Smoke already starting to filter back into the KJAC vicinity
this morning, with vis restriction through 18Z. A weak cold
front moves across the aerodromes east of the divide today, with
a modest north wind shift. Gusts will remain at or below 15kts
behind the front, and decrease at sunset. The associated trough
will bring some high clouds across most of the state this
afternoon and tonight.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Air Quality Alert until 1 PM MDT this afternoon for WYZ007-013-
016>018.

&&

$$

DISCUSSION...Hattings
AVIATION...Straub