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000
FXUS65 KRIW 222340
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
540 PM MDT Thu Apr 22 2021

.SHORT TERM...This evening through Friday night
Issued at 248 PM MDT Thu Apr 22 2021

The next cold front is on the doorstep of northwest WY this
afternoon, and should be sweeping across the state through the
night tonight. There is enough cold air and lift associated with
and behind the front that some snow accumulations are still
expected for the northern mountain ranges, generally reaching 1 to
4 inches by Monday evening. Any precipitation reaching the lower
valley floors will likely remain as rain through Friday morning,
mainly for the Big Horn Basin. The cold pool behind the front
generally remains east of the Divide tomorrow, so those areas
will struggle to get out of the 40s, while southern WY gets into
the 50s with better cloud breaks.

.LONG TERM...Saturday through Thursday
Issued at 248 PM MDT Thu Apr 22 2021

The long-term starts off on Saturday with some ridging over the
Cowboy State at 12Z. The next system from the west looks to start
impacting far western areas as early as 18Z Saturday. The main
story from then through Monday is precipitation over for areas
west of the Divide, as the trough near the West Coast starts to
amplify. For areas west of the Divide, liquid amounts look to be
on the order of around .5 to .75 inches with some areas near the
Idaho border possibly having close to an inch. Temperatures at
700mb range between 0C to -4C, so probably much of the
precipitation would be in the form of rain or a mix or rain and
snow with some light accumulations possibly mainly at night.
Further shifts can pinpoint if snow looks to be significant, but
at this point it does not seem to be a big factor. For areas east
of the Divide, expect seasonal high temperatures and dry
conditions for both days of the weekend, except in the Bighorns.
By Monday afternoon into Tuesday, the moisture finally starts
pushing east of the Divide, but liquid amounts are expected to be
much less (more in the area of around a quarter of an inch).
While temperatures look to be quite a bit cooler east of the
Divide for Monday and Tuesday, rain looks more likely in these
areas. Models diverge a good bit starting Wednesday, but overall
it looks like dry conditions with a ridge and high temperatures
moving back to near or above normal by the end of the period.

&&

.AVIATION...For the 00Z TAFS through 00Z Saturday

Expect VFR conditions to prevail throughout the TAF period for
most of the terminals. A cold front is expected to start
impacting northern areas with some VCSH at the start of the TAF
period. These showers will change over to snow by 03Z and mainly
impact KCOD and KWRL. MVFR conditions will be possible at KCOD by
12Z, as snow moves over the area. Precipitation will become
confined over the northern mountains by 18Z, with breaks in the
clouds in the afternoon. Gusty winds will return to KBPI, KPNA and
KRKS by 18Z.

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

&&

.FIRE WEATHER...
Issued AT 248 PM MDT Thu Apr 22 2021

A cold front will move across the state tonight and tomorrow,
bringing another round of light rain and snow to northern WY.
Winds behind the front are not expected to be gusty, so overall
mixing and dispersal remain fair through the rest of the week.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Straub
LONG TERM...Clayton
AVIATION...Clayton
FIRE WEATHER...Straub