Green River, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

763
FXUS65 KRIW 231115
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
415 AM MST Sat Nov 23 2024

.KEY MESSAGES...

- Light to moderate snow expected for western and southern
  Wyoming today through Sunday.

- Elevated fire weather likely for Natrona and southeastern
  Fremont Counties this afternoon.

- Cooler and somewhat unsettled for next week, but no major
  storms are expected at this time.

&&

.DISCUSSION...
Issued at 247 AM MST Sat Nov 23 2024

The weather for today reminds me of one of my favorite songs when I
was first getting into music when I was a small lad of 10 years old
in the early 80s. That song is by the queen of rock at that time,
Pat Benatar and the song is "Fire And Ice", but the ice is
replaced by snow.

We will start with the cold part of the system. Radar is showing
some precipitation moving into Idaho at this time, and this will be
spreading into Wyoming this morning and continuing into Sunday. The
heaviest is expected from this afternoon into early this evening
with the passage of the Pacific cold front, with lighter snow
expected after that with moist upslope flow. There has been good
model consistency in having the heaviest snow from southern
Yellowstone and the Tetons. Both locations have a better than a
3 out of 4 chance of seeing 6 inches of snow or more. The
chance of a foot of more has gone up to 40 percent in some
portions of Yellowstone Park, but remains low elsewhere. Because
of this, along with likely impacts to Teton Pass, we have
issued Winter Weather Advisories for the above areas. I can`t
rule out a few locations getting over a foot, but this would be
in areas that have basically no impacts to human activity. We
also gave thought to an advisory in the Wind River Mountains,
where there is a greater than 1 in 2 chance of 6 inches or
more. However, this would only be in the highest elevations,
with the main area of concern, South Pass, only having a 1 in 3
chance of 2 inches or more. So, no advisory here since impacts
would be minimal. At this point, the western valleys have at
most a 1 in 4 chance of 4 inches or more, so again, no
advisories. It may be warm enough for the precipitation to start
as rain before changing to snow. Snow will then spread into
southern Wyoming later tonight, including Interstate 80. There
will likely be a small accumulation with at 1 in 2 chance of an
inch in places like Rock Springs, Farson and Pinedale. Again,
advisory level amounts are unlikely as the chance of 4 inches or
more maxes out at Kemmerer at 1 out of 5. Some guidance,
especially the GFS, shows an area of snow over Casper Sunday
afternoon with some jet energy moving over the area. Much more
uncertainty on this though, although the chance of accumulating
snow has increased here.

Now onto the concern of fire. Southwest flow ahead of the front
will bring windy conditions to the favored areas, like Muddy
Gap through Casper, with anywhere from a 1 in 2 to a 4 in 5
chance of wind gusts to 40 mph. Humidity could be rather low
today as well, as dewpoints will drop into the single digits.
These would be Red Flag Conditions, but fuels are not critical
right now. So, we will issue fire weather statements for today.
This threat should end this evening as dewpoints climb as the
cold front passes. Otherwise, it will be a rather mild day east
of the Divide with some areas making a run at 60 degrees and
many of the lower elevations seeing highs in the 50s.

Shortwave ridging should then bring quieter weather for Monday with
only a few showers in the western mountains. The next potential
weather maker then moves in for Tuesday as the upper level low off
of the Pacific Northwest Coast moves onshore and opens into a trough
as it moves toward the Great Basin. Most guidance shows the most
snow remaining across Colorado where the best upper level forcing
will be found. Some moisture may creep far northward enough to bring
some snow to southern Wyoming though. Still uncertain on
details here. Mainly dry weather should then return for
Wednesday. A weak Alberta Clipper may brush by the area for
Thanksgiving, but it will have little moisture to work with so
any snowfall will be on the light side. Temperatures will be
cooler much of next week when compared to much of this week, but
will only fall back to near normal levels with no really cold
air expected for the next seven days as we head toward December.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 410 AM MST Sat Nov 23 2024

BKN-OVC FL150-250 skies will continue over the area this
morning. Winds will increase at most terminals through 18Z, with
gusts over 30 kt to be fairly widespread across the forecast
area during the afternoon. Snow will begin developing across
western Wyoming during this time, leading to MVFR/IFR conditions
at KJAC through the afternoon. Snow will be on the decrease by
early evening, though there is still the potential for lingering
showers to keep at least occasional impacts at KJAC through
late evening. KBPI and KPNA will have a lesser chance of
impacts, but will likely see showers in the area by 00Z. Wind
will similarly decrease by this time. Snow chances will increase
from KRKS to KCPR after 06Z, with another wave likely impacting
KJAC during this time as well.

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

&&

.FIRE WEATHER...
Issued at 247 AM MST Sat Nov 23 2024

A combination of humidity falling into the teens and wind
gusting over 40 mph will bring elevated fire weather to Natrona
and southeastern Fremont Counties this afternoon. These
conditions should ease after sunset as relative humidity rises
as a cold front approaches the area.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 AM this morning to 5 PM MST
Sunday for WYZ001-012.

&&

$$

DISCUSSION...Hattings
AVIATION...LaVoie/Myers
FIRE WEATHER...Hattings