233
FXUS65 KRIW 232120
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
220 PM MST Sat Nov 23 2024

.KEY MESSAGES...

- A weather system brings impacts across western and southern portions
  of the state with moderate snowfall in the mountains and
  light snow across the lower elevations.

- Gusty winds and dry RH values will lead to elevated to near critical
  fire weather conditions over portions of Natrona and Fremont
  Counties this afternoon.

- Mainly quiet and cooler weather is expected for the upcoming
  week with chances for western mountain snow by the middle of
  the week.

&&

.DISCUSSION...
Issued at 1151 AM MST Sat Nov 23 2024

The weekend is looking to start off quite unsettled across much of
the Cowboy State as a Pacific system nears the region. Light snow is
already starting to make its way into far western portions of WY
this morning. Precipitation will continue to spread eastward
throughout the day as a cold front sweeps across the state this
afternoon/evening. Ahead of the front winds will be breezy to gusty
in some areas with the Wind Corridor seeing the strongest gusts of
35 to 45 mph. Temperatures will be mild for much of the state with
highs in the 30s west of the Divide and low 50s east of the Divide.

Impacts regarding this incoming system will vary across the CWA.
Starting off in western WY impacts will mainly be limited to the
mountains. Snow is expected to continue throughout the day and into
Sunday with the heaviest arriving this evening with the passage of
the cold front. Snow accumulation will vary with the highest amounts
expected across the Tetons and Pitchstone Plateau. Currently there
are Winter Weather Advisories in effect for these locations due to
there being a greater than 60% chance of seeing 6 or more inches of
snow. Other western mountains such as the Wyoming, Salt, Gros
Ventre, and Absarokas will see snow but likely lower in amounts,
ranging from 3 to 6 inches with higher amounts possible in
isolated areas. Lower elevation western valleys may see a
periods of light snow as the system moves through. Impacts will
be minimal due to snowfall being mainly light with Jackson Hole
and Star Valley seeing around a 50% chance of seeing 2 or more
inches of snow. Tonight snow will begin to spread south across
portions of Sweetwater County including along the I-80 corridor.
Snow is expected to remain light with around a 30% chance of
seeing 1 or more inches of snow. By Sunday morning snow spread
east into portions of Natrona and Johnson Counties with little
to no snow accumulation expected. The system pulls out of the
region by Sunday afternoon with chilly but around seasonable
temperatures lingering.

Another thing to note for today will be windy and dry conditions
across portions of Natrona County. These windy and dry conditions
will lead to elevated to near critical fire weather conditions with
the only limiting factor being fuels. Winds will periodically gust
over 40 mph with min RH values ranging from 10 to 15. Fire weather
conditions will dissipate this evening as dewpoints increase with the
passing of a cold front.

The upcoming week will be mostly uneventful with much of the CWA
seeing dry and seasonable weather. Temperatures will be on the
cooler side for Monday with chilly air lingering behind the system
that is currently moving into the state. Lows Monday morning will
range from the single digits to low teens west of the Divide and in
the upper teens east of the Divide. Depending on how quickly skies
can clear out and how much snow accumulates across surfaces lows
Monday morning may be much cooler across western valleys. The rest
of the week will see around seasonable temperatures with highs in
the 30s and 40s. As mentioned earlier most of the state remains
quiet through the week with the only exception being portions of
western and southern WY. This is due to another disturbance moving
into the region by mid week. However, models show this disturbance
moving well to the south of the CWA with some precipitation clipping
western mountains and far southern portions of WY. Overall, the
upcoming holiday week looks rather quiet and seasonable with a
chance for some light snow Tuesday and Wednesday across western
mountains and southern portions of the state.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 220 PM MST Sat Nov 23 2024

VFR conditions for the start of the period as snow will trickle
down into western portions of the CWA to affect JAC shortly
after the start of the period. This will spread east to BPI/PNA
by 06Z, and then RKS/COD after 12Z. Prob30 groups for these
locations with lower confidence outside of JAC (even though this
has not come to fruition as of yet). MVFR ceilings/visibility
with light snow when it does occur. Even so, expect the gusty
winds to diminish overnight after the start of the period a
cold front pushes through and relaxes the gradient behind it.
Lower but still VFR at locations that will remain dry. Ceilings
will lift to the mid levels by 12-15Z with lingering lower at
RKS. Improvements east of the Divide to the upper levels by the
end of the period and to the west for the next TAF cycle.

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 1151 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 until 5 PM MST Sunday for WYZ001-012.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...Lowe
FIRE WEATHER...Dziewaltowski