515
FXUS65 KRIW 180650
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1250 AM MDT Wed Sep 18 2024

.KEY MESSAGES...

- Strong winds off the east slopes of the Absarokas and Bighorns
  through midday.

- Widely scattered rain showers (snow for higher terrain) for
  the northern half of the CWA off and on all day Wednesday.

- Dry conditions Thursday with cooler temperatures and sporadic
  precipitation chances Friday and over the weekend.

&&

.DISCUSSION...
Issued at 1234 AM MDT Wed Sep 18 2024

IR currently depicts a classic comma cloud signature from the
high plains to the northern Rockies with much of the colder
cloud tops out of the state. Radar shows some lingering rain
showers and light snow for the higher terrain across northern
parts of the CWA that will continue to wrap around off and on
throughout Wednesday. The cold front is now well to the east
with ample CAA pushing into the state reinforcing the gusty
westerly winds through the morning hours. Boundary layer winds
have 50 plus knots that could mix to the surface under the ample
cloud cover not capped aloft. The main focus areas for any high
winds will be off the east slopes of the Absarokas funneling
through the Cody foothills, as well as across the Rattlesnakes
to Natrona County. Winds will finally start diminishing towards
noon Wednesday and into the afternoon hours as the gradient
weakens in wake of the occluded front exiting to the east with
the main upper level low. Behind it will be induced ridging for
Thursday that will dry out the state but continue with the
cooler, more seasonable temperatures to end the work week and
over the weekend for the long term.

Next up will be another upper level low making its way down the
west coast towards the Four Corner Region. Models are now
indicating more alignment with one another pushing it further
south with less of an impact to the CWA. Cooler temperatures
will still be had with breezy winds Friday and into the weekend,
but precipitation chances look to be more minimal as the
shortwaves spin around the aforementioned low. Higher terrain
look to be most impacted with some weak mountain snow as well as
some rain showers for south central Wyoming as the low tracks
east across the southern states. The main jet will be cut off to
the north keeping the more potent lows with much colder air
near the Canadian border and into Canada. Longer term forecasts
have much model disagreement with some interesting weather
patterns to come by mid next week all dependent on some
trough/low tracks coming down from the GOA through the Pacific
northwest. Time will tell, so stay updated in the coming days.
All in all, once this current upper level low track eastward
later today, expect calmer yet somewhat unsettled weather to
come keeping the cooler temperatures going forward.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1002 PM MDT Tue Sep 17 2024

An upper low is currently moving across northwestern Wyoming. This
will keep shower chances going at KCOD, KJAC, and KWRL through the
night. KJAC is favored to see prevailing MVFR ceilings through
Wednesday morning. Most terminals across central and northern
Wyoming will see a gusty wind - KCPR through the night, and then
KCOD, KLND, KRIW, KRKS, and KWRL mid to late Wednesday morning.
Gusts of 25 to 40 knots are expected. Additionally, showers will
linger across northern Wyoming Wednesday afternoon, most likely to
impact KCOD, KJAC, and KWRL. Wind and showers will decrease as skies
begin to clear after around 02Z Thursday.

Please see the Aviation Weather Center and/or CWSU ZDV and
ZLC for the latest information on smoke, icing, and turbulence
forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until noon MDT today for WYZ003-019-020.

&&

$$

DISCUSSION...Lowe
AVIATION...Myers