217
FXUS65 KRIW 081717
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1117 AM MDT Wed May 8 2024

.KEY MESSAGES...

- Showers continue to spread across the state, gradually moving
  in from the north to the south.

- Precipitation will become widespread by the early afternoon
  with mountain snow and rain elsewhere.

- A brief transition over to snow is possible Thursday morning
  in low elevation areas. However, impacts from this will be
  minimal to non existent for most.

- Quiet and mild weather make a return to the Cowboy State for
  the weekend.

&&

.DISCUSSION...
Issued at 316 AM MDT Wed May 8 2024

Winds have continued to howl through the overnight hours here at the
office with periodic gusts of 40 to 50 mph. Thankfully, the winds
finally do look to diminish during the day today. Winds will be
breezy today, however much weaker than they have been compared to
the past few days. The pesky Pacific low begins to trek back to the
southwest. The weather over the next 48 hours will be the reversal
of Sunday and Monday. Showers will spread across the state from the
north to the south, dominant flow will be from the N/NE, and areas
that saw little precip likely see some. Basically if you did not see
much in terms of precipitation when the low tracked northeast across
the state, you will likely see something as it tracks back
southwest. Overall, the impacts on the CWA from this one system will
end up being perfectly balanced, as all weather systems should be.

As mentioned earlier the Pacific low and its unorganized remnants
will move back across the state over the next 48 hours. Showers will
continue to develop across the state from the north to south and
gradually become widespread during the morning. Winds are expected
to decrease compared to the past few days but still remain breezy
across most of the state. Flow will begin to shift today with winds
becoming north/northeasterly by the afternoon. Areas that favor such
flow like the eastern slopes of the Wind River Range, Absarokas,
Casper Mountain and Bighorns have seen winter highlights issued. The
Bighorns have a Winter Storm Warning in effect due to additional
snow accumulation of 8-16 inches by Thursday morning. Other areas
such as the Absarokas, eastern Wind River Range, and Casper Mountain
have been issued Winter Weather Advisories. Snow accumulation looks
to range from 8 to 14 inches with the highest peaks seeing amounts
greater than 16 inches. Due to the longer duration and elevation
dependency of the snowfall, warnings were not issued even though
snowfall amounts may reach criteria.

Lower elevation valleys/basins will see some cooler air get funneled
in due to northerly flow. This flow shift will help usher in some
cooler air, with 700 mb temperatures ranging between 4-6 C for
Thursday morning. Tuesday morning the possibility of snow was
mentioned in some low elevation areas. Unfortunately for any snow
lovers hoping for some late season flakes, temperatures will not be
on your side. Models have continued to keep low temperatures
Thursday morning 3-5 degrees above freezing. This will likely make a
transition over to snow difficult. However, if all things line up
with the heaviest precipitation falling during Thursday morning and
enough cooler taking place there still is a chance. Currently the
chances for central basins are slim, with a (10-30%) of seeing snow
in places like Lander Thursday morning. The better odds will be
across Sweetwater and Sublette Counties where there is a (20-50%)
chance of seeing 0.1 inches of snow accumulation. Showers will
continue across low elevations during the morning and afternoon
Thursday with most if not all places seeing rain. Precipitation
begins to wind down Thursday evening, with a few lingering showers
going into early Friday morning.

End of the week...

An area of weak ridging begins to move into the region Friday.
Quieter and milder weather will return by the weekend with highs
returning to normal or above normal values. Winds will become light
and variable which will be a welcomed change for many. Chances for
precipitation look to possibly return for the start of next week,
mainly in the form of convective showers.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1116 AM MDT Wed May 8 2024

Rain/snow chances occur at all sites today. MVFR to occasional IFR
conditions expected with precipitation, with mainly MVFR cloud
ceilings. KCOD sees rain through the TAF period, with heavier
showers passing through at times, which could bring IFR conditions;
the best chances for these will be overnight. A heavier push of
showers moves through KJAC and KRKS this afternoon and evening,
later for KRKS. This push would bring the best chances for IFR
conditions. There is some uncertainty with how long precipitation
lasts overnight, for the sites with rain/snow chances overnight.
WIll have to reevaluate for future TAF issuances as guidance
currently has mixed opinions. Upslope favors prolonged chances at
KLND and KRIW.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon MDT today for WYZ001.

Winter Weather Advisory until 3 AM MDT Thursday for WYZ002.

Winter Storm Warning until 6 AM MDT Thursday for WYZ008-009.

Winter Storm Warning until noon MDT today for WYZ012.

Winter Weather Advisory until 9 AM MDT Thursday for WYZ015.

Winter Weather Advisory from 4 PM this afternoon to 6 AM MDT
Thursday for WYZ022.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...Wittmann