Odonnell Spur, Wyoming Weather Forecast Discussion

380
FXUS65 KRIW 051011
AFDRIW
Area Forecast Discussion
National Weather Service Riverton WY
411 AM MDT Sun Oct 5 2025
.KEY MESSAGES...
- Another round of precipitation returns across the region this
  afternoon, with continued mountain snowfall at higher
  elevations.
- Freeze warnings have been posted for areas of southern and
  northern Wyoming, with lower confidence across central
  Wyoming.
&&
.DISCUSSION...
Issued at 219 AM MDT Sun Oct 5 2025
The first round of precipitation from the large-scale trough is
shifting east this morning, leaving behind a nice coating of
snow across area passes and higher elevations. There will be a
brief gap in most precip this morning before the next round
sweeps in on the back side of the trough from the northwest.
This will bring more lower elevation rain/higher elevation
snowfall today and tonight. Forecast remains above 0.10" for all
areas through sunrise Monday, with a quarter to a half inch
additional rainfall across Fremont and Natrona Counties. Higher
elevations will also continue with snowfall, with another 3 to 6
inches above 8000 feet.
As the next wave sweeps to the east tonight, skies will
gradually clear from west to east. The amount of cloud cover
overnight will directly impact how cold temperatures fall.
Models have held on to cloud cover longer overnight, so
confidence in overall coverage of freezing temperatures is
lower. Confidence and probabilities are best across Sweetwater
County into the Green Mountains, and across the Cody Foothills
(both 60 to 70%), so have upgraded to Freeze Warnings for those
zones for tonight, with remaining areas of central WY holding
onto Watches for now, to monitor newer forecasts for changes in
cloud cover. Any cloud cover remaining Monday morning will clear
out during the afternoon, leaving a better opportunity for a
freeze for remaining areas of central WY Monday night/early
Tuesday morning.
By midweek, H5 ridging reestablishes across the Rockies,
bringing temerpatures back closer to normals in the 60s for
highs and 40s for lows.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 407 AM MDT Sun Oct 5 2025
Widespread MVFR to occasional IFR conditions for most TAF
sites. Another round of mainly rain pushes in west of the Divide
after 12Z and pushes to the east after 14 to 16Z Sunday. This
should linger with periods of light rain all day Sunday
afternoon and evening with MVFR to local IFR conditions if
rainfall becomes heavier at times. Winds will remain light to
moderate throughout less than 10 to 15kts.
Rain will linger towards sunset west of the Divide before
pushing east towards the end of the period. East of the Divide
TAF sites should see light rain through the end of the period
not letting up until after the 06Z timeframe into the next TAF
cycle. Patchy fog may occur at some sites, especially in
vicinity of KJAC where there may be some clearing after 06Z
Monday, but not enough confidence to include in the TAF at this
time.
Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on smoke, icing, and turbulence
forecasts.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MDT this evening for WYZ002-
008-009-012-015.
Freeze Warning from 1 AM to 10 AM MDT Monday for WYZ003-019-
028>030.
Freeze Watch from late tonight through Monday morning for
WYZ004>006-010-011-017-018-020.
Freeze Warning until 10 AM MDT this morning for WYZ013-016-023-
027.
&&
$$
DISCUSSION...Straub
AVIATION...Hattings

NWS RIW Office Area Forecast Discussion