838
FXUS65 KRIW 181040
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
440 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 /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 430 AM MDT Wed Sep 18 2024

VFR conditions will prevail at all locations but JAC, where
MVFR will be the main prevailing ceiling through the morning
hours until 18Z. Mid level ceilings at all other locations with
breezy winds gusting up to 25 kts, highest at CPR up to 40kts
and COD/LND up to 30 kts. Light rain showers at JAC/COD/WRL will
continue through much of the day before ending by 23-00Z as the
main low exits to the east. Winds will diminish after 01-02Z as
an inversion is able to cap them off aloft with scattering mid
to upper level clouds improving overnight into Thursday morning.


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...Lowe