Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 231906
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
106 PM MDT Sat Mar 23 2024

.KEY MESSAGES...

- Snow continues to push into the western mountains today
  through Sunday, with steady and moderate snow.

- Snow reaches east of the divide Sunday, with most areas only
  seeing light amounts.

- Gusty north winds expected for northern WY tonight and Sunday.

&&

.DISCUSSION...
Issued at 1244 PM MDT Sat Mar 23 2024

The large-scale trough continues to make landfall along the
PacNW today, with broad southwest flow ahead of it. This
moisture tap ahead of it, along with diffluence aloft, is
bringing both orographic and atmospheric lift to produce
snowfall across the western mountains. These two features peak
this evening, which is when the fastest snow accumulation is
expected. As the trough moves east tonight, the moisture flow
begins to decrease aloft. At the sfc, winds shift more from the
northwest, which is less effective for uplifting snowfall out
west. With this somewhat more limited snowfall period, overall
snow totals will remain in Advisory levels at higher elevations,
which are already covered and need no changes. For the lower
basins out west, slightly drier sfc air along with downsloping
will limit snowfall at lower elevations, so will not need
advisories for Jackson Hole or Star Valley.

East of the Divide, the trough moves through tonight and
tomorrow morning, bringing a good cold front southward across
the region. With temperatures falling considerably overnight
tapping moisture, some snowfall is expected. Most areas will
remain light, as the moisture is limited, precip will be more
focused along the weak front as it moves through, and will start
as a mix of rain and snow. Concerning areas for snow will be
areas just north of the Owl Creek and Bridger Mountains,
including Thermopolis, and along the Wind River Range, where
upsloping will be greatest. Latest snowfall totals for Hot
Springs County remain 3 to 5 inches, taking into account any
melting from warmer ground temperatures, so will not be
expanding the Advisories into those areas.

The front will also be bringing a considerable northerly push of
cold winds as it barrels through the Bighorn Basin and across
Johnson and Natrona Counties. Winds tonight and tomorrow will
easily be gusting 25 to 35 mph, with a few gusts near 50
possible.

Cold temperatures behind the front will fall into the teens
Sunday night with clear skies and light winds. It will take a
few days to recover back to near where we`ve been the past
several days, right before the next weather system attempts to
break into the Northern Rockies.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1111 AM MDT Sat Mar 23 2024

A complex weather system is moving through the next couple days. In
summary, it brings rain and snow shower chances, with periods of
heavier snow possible. A cold front sweeps through tonight, bringing
a north wind and better snow chances for those favored in north
flow, such as KLND, KWRL, and to some degree KRIW. TAFs reflect
best estimates of rain or snow. Rain will be more likely during
daytime, transitioning to snow overnight and once the cold front
moves through (known by site having north flow). Outside the main
precipitation chances, have carried VCSH, as models are very unsure
of exact timings and coverage. There is a possibility for some
lightning today, mainly west of the Continental Divide.

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 from 6 PM this evening to 6 PM MDT
Sunday for WYZ001-002.

Winter Weather Advisory until 6 PM MDT Sunday for WYZ012-014-
015-024.

&&

$$

DISCUSSION...Straub
AVIATION...Wittmann


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