Mills, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

969
FXUS65 KRIW 021109
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
509 AM MDT Wed Apr 2 2025

.KEY MESSAGES...

- Snow continues across the Bighorns, northern Johnson County,
  and Casper Mountain Wednesday.

- Showers Thursday and Friday but less widespread.

- Warming and dry trend over the weekend and into next week.

&&

.DISCUSSION...
Issued at 106 AM MDT Wed Apr 2 2025

Areas of snow showers moving across the Wind River Basin down
into eastern Sweetwater County ongoing through near sunrise
Wednesday morning. The NAMNest is handling this pretty well,
although other HiRes models not too far off having it dissipate
by this timeframe. Otherwise, the near stationary boundary to
the north will bring in another round of snow showers out of
Montana along the shortwave skirting around the main upper level
trough dipping to the south of the CWA. By early afternoon, the
Bighorns and northern Johnson County will see continuous snow
showers. Additional accumulations of higher confidence up to 4
to 8 inches (70-80%) for the Bighorns and 1 to 3 inches for
northern Johnson (50-60%). As winds increase through the
afternoon with the stronger gradient from the aforementioned
surface boundary, expect north to northwesterly gusts up to 25
to 35 mph that will limit visibility for these stretches of
interstate out of Buffalo. Mid to late afternoon, the highest
snow rates across Casper Mountain as the boundary sage south,
east of the Bighorns, also coupled with the stronger winds.
Elsewhere, some sporadic snow showers across the Absarokas and
Yellowstone, and more organized through the Wind River Basin. By
4-5PM, expect a subtle low to push a rain/snow mix through
about sunset before lingering as snow into the late evening
hours as it pushes southeast into Sweetwater County once again.
Regardless, the showers will dissipate towards midnight
lingering for Yellowstone by sunrise Thursday morning.

With the lingering surface boundary near the Montana state line,
another round of developing showers by mid afternoon, mainly
across the northern parts of the CWA. With a bit stronger
daytime heating, some instability off the Absarokas into the
western Bighorn Basin could see some isolated thunder chances
with 100-200 J/kg expected. This is where the stronger of the
PVA anomalies will be from the more elongated upper level
trough progressing a bit further east. Coverage a bit more
limited, mainly driven by daytime heating with more limited
accumulations expected for the higher terrain. With the upper
trough continues eastward dipped well to the south, more limited
coverage for eastern counties for any shower activity Friday
afternoon.

Overnight Friday into early Saturday morning, expect the main
finger of the PFJ finally eject the upper trough to the east of
the CWA allowing for the cold front to drop southeastward into
the high plains. This will give way to the more seasonable and
slightly cooler Saturday afternoon high temperatures with
improved conditions expected. Strong ridging builds into the CWA
from the west with increasing convergence aloft. The PFJ
remains well north and eastward aiding in dry weather into next
week, despite the more meridional upper level pattern. This
ridge will set in place through about mid next week giving way
to a warming trend, resulting in above average temperatures. A
couple shortwaves look to pass to the north with the southward
moving PFJ but impacts look to be limited with minor
precipitation chances for northern zones Tuesday through
Thursday. Otherwise, long term outlooks trend towards stronger
ridging, and dryer/warmer than average conditions expected
heading into the middle of the month.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 509 AM MDT Wed Apr 2 2025

Snow showers will once again be around today. Models indicate they
are less numerous compared to the previous couple days, therefore
chances are less for a terminal to be impacted. That said, PROB30
groups have been included for many sites as 20 to 30 percent chances
will still be around this afternoon into late evening. Quick changes
to flight conditions would occur if a snow shower does impact a
terminal, ranging from VFR to IFR. Even locations without a PROB30,
like KBPI and KRKS, may still have a couple snow showers around, but
chances are too low to include in TAFs.

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 until 6 PM MDT this evening for
WYZ008>010.

Winter Weather Advisory until 6 PM MDT this evening for WYZ022.

&&

$$

DISCUSSION...Lowe
AVIATION...Wittmann