Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 201014

Area Forecast Discussion
National Weather Service Riverton WY
414 AM MDT Fri May 20 2022

.SHORT TERM...Today through Sunday night

As I write this around 2:30 am, much of the area is in a lull
between the first departing wave and a second one which is now
getting ready to cross the Wyoming border. This will spread the next
round of showers across much of the area, with the most numerous
across the mountains. With cooler air in place, many of these may
fall in the form of snow, even in the daylight hours with the rather
cold air aloft. Accumulations would remain on the light side though,
and much may not even stick during the day given the strong late May
sun. The mountains may see a few inches of snow though. The Weather
Prediction Center amounts look too high though. If these amounts
fell, it would be in the highest elevations where impacts would be
slim to none. We will issue a Special Weather Statement to cover for
it. The other concern is wind. We have already seen some gusts to
near 50 mph across the north with the second push and these will
spread southward. The difference with today compared to yesterday is
that the jet is further south and downward forcing will be less. So,
widespread high wind is not expected. There could be a local high
wind gust in a place like the Buffalo airport, but as the late,
great George Carlin said as the hippy dippy weatherman, "No one
lives at the airport." We will issue a Special Weather Statement to
cover for this as well. As for thunderstorms, the best chance would
be across the west. The Storm Prediction Center covers this fairly
well so we followed it closely. The main threat would be small hail
given the low wet bulb zero levels. And really, any shower today
could have small hail or graupel with the cold air aloft.

Showers should taper off during the evening hours as this push moves
away. And the big question tonight is how much clearing will there
be. And this will determine how cold it will get. However, most
areas should see below freezing temperatures. However, since it is
not yet Memorial Day and almost all areas have had temperatures
below freezing within the past week, we will not issue any frost or
freeze highlights. But again, (noticing a trend here), we will
continue the special weather statement for it.

Saturday will be another chilly day. However, some shortwave ridging
will be passing over the state. This will have two effects. One, it
will substantially turn down the wind for most areas. Second, the
coverage of showers should be reduced. Northwest flow will keep them
going, especially in the mountains, but most of the lower elevations
should be dry most of the time. On Sunday, another wave will
approach and once again increase the chance of showers, especially
across the west. The difference with this wave is that the jet will
be across Colorado, and this should keep winds down somewhat.
Temperatures will gradually warm through the weekend, but remain
well below normal for all locations.

.LONG TERM...(Monday through Thursday)
Issued at 400 AM MDT Fri May 20 2022

The unsettled weather pattern will continue Monday and Tuesday as
the models bring in weather systems both days in the northwest
flow aloft. Scattered rain and mountain snow showers will be the
rule both days with isolated thunder possible. Conditions will dry
out Tuesday night with decreasing clouds. Wednesday and Thursday
will be dry over the region as high pressure moves into the area.
Thursday looks to be breezy in the afternoon with elevated fire
weather conditions in some locations. High temperatures Monday and
Tuesday will be in the 50s to lower 60s with 30s and 40s in the
mountains. Highs Wednesday will warm into the 60s to lower 70s.
Thursday will see high temps in the 70s with some 80s east of the


.AVIATION...(For the 12Z TAFS through 12Z Saturday)
Issued at 400 AM MDT Fri May 20 2022

VFR conditions will occur most of the time today and tonight at
the terminal sites. MVFR to IFR conditions will occur at times
today through 03Z at some locations as scattered snow showers
occur, reducing visibility and lowering ceilings. Thus, expect
changing weather conditions today through 03Z. A gusty wind will
occur at many locations today, decreasing toward 03Z this evening.
Gusts around 30 knots will be common.

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



Today will be a blustery and cold day across the state with a
scattering of showers and isolated thunderstorms with the best
concentration across the west. The strongest wind is expected in
northern Wyoming but widespread high wind is not likely. Relative
humidity will remain above critical levels. Mixing and smoke dispersal
will be generally good to excellent in the afternoon. Cool and
showery weather will continue on Saturday although there will be
much less wind.





SHORT TERM...Hattings
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