762
FXUS65 KRIW 192058
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
258 PM MDT Sat Oct 19 2024

.KEY MESSAGES...

- Returning to seasonal temperatures and dry weather today, with high
  pressure dominating the pattern for at least the next week.

- Slight precipitation chances (5 to 10%) for Sunday across southeast
  portions of the area will occur thanks to a stalled low to
  our south.

- Only other precip chances (15 to 20%) this week come across
  the north with a shortwave passage on Tuesday.

&&

.DISCUSSION...
Issued at 106 PM MDT Sat Oct 19 2024

We finally got to experience some wintery weather yesterday. Low
temps this morning officially ended the growing season for all of
us, as we woke up to clear blue skies. Patchy fog developed this
morning in the wake of the precipitation and cold front yesterday.
Most notable areas of fog were in the Wind River Basin, eastern
Sweetwater County, and in the Jackson Valley. By 11 AM MDT, the fog
had mostly scattered out, though some areas of fog over Boysen
Reservoir and Wind River and across southern WY are still evident on
Satellite as of Noon. What also is evident on satellite are the snow-
covered mountain ranges for the first time this season, which are
certainly a welcome sight. Unfortunately, the snow will not stick
around too long as high pressure builds today. Temperatures will
remain below normal today, but by tomorrow will return to seasonal
values. High pressure will continue to dominate the weather pattern
through the next 7 to 10 days, and thus, we return to seasonally
warm and dry weather.

The low that brought the rain and mountain snow and colder weather
yesterday has stalled out over the Four Corners area. A shortwave
moving in from the PACNW will push this low eastward Sunday night
into Monday. The low will also retrograde northward a bit, though
latest model runs limit this northward movement. A slight chance (5
to 10%) of precipitation across eastern portions of the region
(mainly eastern Sweetwater County) will be the only real impacts
from this. Have lowered PoPs from the previous forecast, in-line
with mode trends, for the Sunday Night - Monday time frame.

The aforementioned Pacific shortwave will slide to our north Tuesday
and Wednesday. There are slight precip chances (again only 10 - 20%)
across the north, with best chances for precip (20 to 25%) across
YNP, and the northern Bighorns Tuesday night. Wednesday will see
temperatures dip a few degrees compared to Tuesday, but will remain
seasonally warm. A series of weak shortwaves will follow for the
later half of the week, but these will also track to our north and
impacts will be negligible at best.

Despite the lack of precipitation for the near future and seasonally
warm weather, winds will remain mostly light through the weekend.
Monday/Tuesday will see slightly increased winds with the shortwave
passage and southwest winds along the wind corridor will be again
slightly elevated late week with the shortwaves to the north
tightening the gradient slightly. Gusts 25 to 35 mph will be common
Thursday and Friday afternoons for the South Pass to Casper
corridor. If there is a positive in this, time of year (shorter
days, cooler nights, and lesser solar angle) will help keep fire
weather to a minimum, however, despite the dry and breezy
conditions, and RHs should generally stay above critical thresholds.

In summary, after one day of cooler and wetter weather, we return to
warm and dry and breezy weather once more with few, if any,
precipitation chances in the near future.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 258 PM MDT Sat Oct 19 2024

VFR conditions prevail through the period. Light winds and a mainly
clear sky continue overnight and into Sunday. A low to the south and
southeast will push some clouds into southern portions of the area
late Sunday morning and afternoon. A light shower is possible (less
than 20%) near KRKS Sunday afternoon, but given the low confidence
have just kept increasing clouds.

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...
None.

&&

$$

DISCUSSION...Hensley
AVIATION...Wittmann