Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 212013

Area Forecast Discussion
National Weather Service Riverton WY
213 PM MDT Thu Mar 21 2019

.SHORT TERM...This afternoon through Friday

Mid to high level clouds will continue to stream over the
southwestern half of the forecast area this afternoon. These
clouds will then move northward over central and northwestern
portions tonight, as precipitation chances increase. Snow showers
will develop over southern portions this evening, spreading over
western portions through the overnight hours. Some of these
showers will briefly move over portions of Natrona County tonight.
The best chance for accumulating snow will occur over portions of
Lincoln County, where 2 to 4 inches will be possible over southern
portions. 3 to 5 inches will be possible on the southern end of
the Salt/Wyoming Ranges. Most of this will occur tonight into
Friday morning, as temperatures rise into the upper 30s to lower
40s Friday afternoon.

These showers will remain confined to far western portions of the
forecast area Friday, with snow in the mountains. A rain/snow mix
to rain will occur in the valleys. Snow levels will range between
6500 to 7500 ft by Friday afternoon. Precipitation amounts are
expected to remain light in the lower elevations, so the threat
for rain on snow is not expected at this time. East of the Divide,
temperatures will remain seasonal Friday, with above normal
readings in the mid 60s expected across the Bighorn Basin and
Johnson County.

.LONG TERM...Friday night through Thursday

Showers continue in the west as the low slowly moves northward
into MT. Showers over Johnson and eastern Natrona counties will
also depart to the east late Friday night. Slight ridging will
then build into WY east of the Divide for a fairly dry Saturday.

The weather system on Sunday and Sunday night brings a chance of
rain and snow to the lower elevations and snow to the mountains.
The GFS and ECMWF models are still in slight disagreement of the
amount of precipitation for the region. Sunday will see cooler
temperatures, cloudy conditions, and showers of rain and snow. This
system will move out of the region through the day Monday, with
decreasing clouds and most of the precipitation ending by noon.
Tuesday is still looking dry and warmer for the area. Another
weather system will impact the northwest starting late Tuesday night
and spreading through the west Wednesday with rain and snow. This
system will move east of the Divide Wednesday night, with Thursday
seeing a chance of rain and snow along the southern areas of the
state, as well as the Bighorn Mountains.


.AVIATION...00Z Issuance

BKN-OVC mid-high level clouds continue over areas west of the
Continental Divide. Some shower activity will occur along the UT-
ID- WY border through this evening. Showers from CO will then move
northward into southern and southwestern WY by 05Z Friday and
continue to spread northward across western portions through 12Z.
Mountain snow and valley rain/snow will be widespread across
western portions between 18Z Friday through 00Z Saturday. Brief
MVFR conditions are possible with any shower activity, although
MVFR ceilings are expected at KBPI by 09Z. Western mountains are
expected to be obscured at times tonight through Friday. Winds
will remain to be mainly light.



A few showers are possible over zone 277 today, but most areas
should remain dry. Elsewhere, expect a dry and mild day although
with a few more clouds. Winds will continue to remain light, with
gusty areas over the southern and eastern zones. Mixing and smoke
dispersal will range from poor in most locations to fair to good
in northwestern Wyoming. There will be a better chance of showers
over western Wyoming Friday.




LONG TERM...McDonald/Swanson
FIRE WEATHER...LaVoie is the U.S. government's official web portal to all federal, state and local government web resources and services.