Saint Stephens Wyoming Weather Forecast Discussion

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FXUS65 KRIW 070256
AFDRIW
Area Forecast Discussion
National Weather Service Riverton WY
856 PM MDT Mon Oct 6 2025
.KEY MESSAGES...
- Cold, near to below freezing, temperatures tonight. Thus, a
  Freeze Warning is in effect for southern Wyoming and lower
  elevations east of the Divide Tuesday morning.
- There is a 40-70% chance of fog development tonight across
  portions of the Wind River Basin, Star Valley, Jackson Hole,
  and eastern Sweetwater County.
- Dry weather with near to above normal temperatures Tuesday
  through Thursday.
- Precipitation chances (30-60%) return Friday and continue
  into next weekend, especially west of the Divide, along with
  cooler temperatures.
&&
.UPDATE...
Issued at 146 PM MDT Mon Oct 6 2025
Precipitation has ended across the area as the previous system fully
departs. Some lower cloud cover remains early this afternoon, but
this is expected to clear in the coming hours as drier air moves in
aloft. This clearing will make for a cold night, bringing sub-
freezing temperatures to many locations that have not yet seen them
this season. Accordingly, a Freeze Warning is now in effect across
southern Wyoming and lower elevations east of the Divide. Fog is
also possible tonight with the best chances (60-70%) across Jackson
Hole, Star Valley, and the Wind River Basin.
&&
.DISCUSSION...
Issued at 212 AM MDT Mon Oct 6 2025
The remaining trough axis continues to drift southward today,
but will still be producing some light precip across central WY
through around noon today. As the trough axis moves south, it
will allow northerly flow aloft to begin to carve out the low
clouds across the state. Most areas should be nearly clear by
late this afternoon. With the core of the coldest temps with
this system still in the vicinity, temperatures will struggle
to reach back into the 50s this afternoon. With clear skies
tonight, another round of freezing temperatures is expected
across all of western and central WY.
Behind this trough, a large ridge builds across the
Intermountain West, paired against a large cutoff low settling
just off the PacNW Coast. This should keep the weather more
tranquil for the latter half of the week, allowing temps to
recover back to near to just above normal in the 60s to near 70.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 451 PM MDT Mon Oct 6 2025
VFR conditions are expected to prevail through the period, with a
mostly clear sky and light winds. Some fog is possible again
tonight; have highlighted these chances with VCFG and FEW008 groups
in the TAFs. Confidence remains low, as most models are not showing
fog, but cold overnight temperatures, a clear sky, and recent
moisture favor fog development again. Will have another chance to
look over things with the next TAF issuance.
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...
Freeze Warning from 1 AM to 9 AM MDT Tuesday for WYZ003>006-
010-011-017>020-028>030.
&&
$$
UPDATE...Myers
DISCUSSION...Straub
AVIATION...Wittmann

NWS RIW Office Area Forecast Discussion