FXUS65 KRIW 111750

Area Forecast Discussion
National Weather Service Riverton WY
1050 AM MST Mon Dec 11 2023

.DISCUSSION...This afternoon through Sunday
Issued at 1034 AM MST Mon Dec 11 2023

Yesterdays shortwave has moved well away from the region, allowing
pressure gradients to loosen up with winds remaining light and calm
for today. A brief lull in weather will take place across central
and eastern WY today. Elsewhere, northwesterly flow starts to
weaken, reducing the upsloping induced snow across northwestern WY.
Snowfall will gradually diminish across the Tetons and Gros Ventres,
with little to no additional snow accumulation expected today.

An upper level trough digs down across the Great Basin
starting late this afternoon and evening. This will cause a shift in
upper level flow to a more westerly/southwesterly direction. This
flow will aid in producing scattered snow showers over parts of the
Salt River and Wyoming Range, southern portions of the Tetons, and
western slopes of the Wind River Mountains this evening and tonight.
Lower elevation areas, such as the Green River Basin and northern
Sweetwater County, may see brief periods of light snow during the
afternoon and evening today lingering into the early morning
Tuesday. Some models have shown the possibility for an isolated snow
shower developing across parts of the Wind River Basin early Tuesday
morning. While this cannot be ruled out, the majority of models
indicate most of the precipitation to remain across southern
portions of the CWA. Overall, trace accumulations are expected, with
an isolated area of maybe an inch at most of accumulation. Impacts
will remain minimal due to the lacking moisture keeping QPF values
low and unfavorable atmospheric dynamics over our CWA.

The upper level trough continues to dig farther south by late
Tuesday, reaching the Four Corners region by early Wednesday
morning. During this time, a closed low develops and moves eastward
over the Southern Rockies and Southern Plains, keeping any impacts
to our CWA too far south.

The second half of the work week will see a large upper level ridge
build in over much of the western CONUS. This ridge will bring back
dry and fairly uneventful weather across the state, while aiding
temperatures in returning to near or slightly above normal values.
Beyond Friday the weather pattern looks to remain rather docile and
uneventful, with little in terms of precipitation chances. Looking
further ahead, current CPC guidances are indicating high
possibilities of 60% to even 80% chances for above average
temperatures and below average precipitation. So unless something
major changes in the weather pattern, there is a good chance that
the snow on the ground in the lower elevations will melt and will
not see a white Christmas. So those of you who have wished for a
brown Christmas, Enjoy!


.AVIATION...For the 18Z TAFS through 18Z Tuesday
Issued at 1050 AM MST Mon Dec 11 2023

MVFR conditions at KJAC will continue for the first few hours of
the TAF period, before improving to VFR. MVFR ceilings and VCFG
will return around 09Z through 14Z. A band of light snow will
occur across portions of southern Wyoming this afternoon,
bringing in lower clouds and VCSH to KBPI, KPNA and KRKS.
Increasing chances of snow will occur at KBPI/KPNA after 00Z, with
MVFR conditions. This band of snow will lift northward through the
night, briefly impacting KLND/KRIW and KCPR between 08Z and 12Z.
Snow is expected to end by sunrise Tuesday morning, with a chance
for lingering MVFR ceilings. Overall, snowfall rates are expected
to be light, but MVFR conditions are expected.

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