Powell, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

708
FXUS65 KRIW 241051
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
351 AM MST Sun Nov 24 2024

.KEY MESSAGES...

- Some snow continues across the area today.

- The next system arrives Monday night into Tuesday with the
  next chance of snow, mainly across western and southern
  Wyoming.

- Quieter and cool weather is expected for the Thanksgiving
  Holiday weekend.

&&

.DISCUSSION...
Issued at 251 AM MST Sun Nov 24 2024

The Pacific trough and cold front is now moving across the area.
Snow is continuing across the west, although it has been slower to
develop across the north. We gave some thought to canceling the
Winter Weather Advisory, but will likely leave it up for now
since probabilistic guidance shows at least a 3 in 5 chance of
an additional 2 inches in the areas with the advisories
(although the intensity should be less). Now it is starting to
jump east of the Divide and across southern Wyoming. Most
guidance, both deterministic and probabilistic, shows amounts
remaining light for the most part. Of the population centers,
only Buffalo has a 1 in 3 chance of an inch or more; other
areas having less than a 1 in 5 chance. Only the mountains east
of the Divide have a chance of 4 inches or more, and these are
in places where impacts are slim to none. So, we will issue no
further highlights. There could be locally higher amounts in
snow banding, but these will be handled with Special Weather
Statements. Temperatures will be cooler behind the cold front,
but given the Pacific origin of the air mass, this will drop
them back to near normal levels for late November.

Snow should end by sunset, followed by ridging building over
the area. With the sky expected to clear quickly, we will have
a much colder night. With the clear sky and cooler air mass, we
have lowered temperatures a few degrees as a result.

Ridging then builds in for Monday, bringing a mainly dry but
seasonably cool day for Monday. The next weather maker then
approaches in the form of the persistent low off of the Pacific
Northwest coast that will move onshore and open into a trough as
it moves eastward. There is still a fair amount of uncertainty
with this system as guidance still differs on timing of arrival,
with some guidance as early as late Monday night and others
holding it off until sometime Tuesday morning. All guidance
keeps the main effects, once again, mainly confined to western
and southern Wyoming with little impact in areas further north
and east. There are also differences in departure time in the
system, ranging from Tuesday evening to Wednesday evening. So,
although we are fairly confident in some impacts to the area,
especially on Tuesday, confidence in details remains low.

Quieter weather then looks to move in for the holiday weekend
as ridging builds across the West Coast. The area will be on
the edge of the ridge so a couple of weak Alberta Clippers may
get close enough to the area for a few impacts, one on
Thanksgiving Day and another over the weekend. These systems are
rather moisture starved though, so any precipitation would be
on the light side and largely confined to northwestern portions
of the area. They will bring some colder temperatures though,
nothing really cold, but some, so we may see some below normal
temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 351 AM MST Sun Nov 24 2024

Snow will remain possible across the forecast area through the
first half of the TAF period as a cold front begins to drop
southward over areas east of the Divide. The best chances will
occur from southern Lincoln County and Sweetwater County, up to
Natrona and Johnson counties this morning. The focus for these
showers will shift to northern portions after 18Z, gradually
ending across the forecast area by 01Z. Confidence is high for
prevailing IFR/MVFR conditions and KRKS and KCPR, with PROB30
groups at other terminals. Otherwise, wind has decreased and
will remain on the lighter side for most through the period,
though KRKS and KPNA will see gusts to 20 knots in the
afternoon. Skies will scatter out through the overnight hours.
Fog formation will be a concern, possibly impacting KCPR, KWRL
and KRIW after 12Z Monday.

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...
Winter Weather Advisory until 5 PM MST this afternoon for
WYZ001-012.

&&

$$

DISCUSSION...Hattings
AVIATION...LaVoie/Myers