Hamilton Dome Wyoming Weather Forecast Discussion

041
FXUS65 KRIW 071827
AFDRIW
Area Forecast Discussion
National Weather Service Riverton WY
1227 PM MDT Tue Oct 7 2025
.KEY MESSAGES...
- Warming temperatures and mostly clear skies will persist through
  Thursday.
- Elevated fire weather conditions are expected on Wednesday,
  especially from Sweetwater County through Natrona County.
- Precipitation chances will return to the area on Friday as the
  next system arrives. Cooler temperatures are expected by
  Sunday.
&&
.UPDATE...
Issued at 1226 PM MDT Tue Oct 7 2025
With the previous system now fully departed, clear skies and warming
temperatures will be the trend through the next few days. One of the
few weather concerns during this period will be elevated fire
weather conditions on Wednesday as winds come up across the Wind
Corridor and humidity drops to around 20 percent. This will be
brought on by the arrival of an upper level jet as well as a
building surface pressure gradient. Otherwise, the forecast remains
on track, with the next precipitation system arriving by the
weekend.
&&
.DISCUSSION...
Issued at 247 AM MDT Tue Oct 7 2025
A chilly start to the day across the Cowboy State this morning as
many locations east of the Divide look to see their first hard
freeze of the season. Temperatures this morning will range from the
low to mid 20s west of the Divide and upper 20s to lower 30s east of
the Divide. A few areas of patchy fog cannot be ruled out this
morning, especially near bodies of water due to the warm water
temperatures. Fortunately, a warming trend is on its way as the cold
Canadian air mass is ushered to the east and high pressure builds in
over the Intermountain West. Highs today will still be on the cooler
side with temperatures in the mid to upper 50s. However, warmer
temperatures settle in for Wednesday with highs returning to the
upper 60s to lower 70s. Warm and dry conditions persist through the
remainder of the work week as high pressure sits over the region.
Looking ahead, long range models are showing a rather potent cut-off
low developing off the coast of the PACNW during the middle of the
week. This low may be the next big weather maker as it gradually
tracks east and inland as early as Friday. However, ahead of the low
will be a plume of tropical moisture associated with the
decaying tropical disturbance Priscilla in the eastern Pacific.
Above normal PWATs attempt to make their way into the CWA
largely due to the anti-cyclonic flow of the high pressure over
the central CONUS. As a result of this moisture, chances for
showers and thunderstorms increase across the state. The timing
of the precipitation and determining the most favorable
locations still remains up in the air at this time due to the
multiple components involved. Models currently paint a bullseye
just to the south of the CWA across portions of Colorado.
However, a slight deviation in one or two components may shift
this bullseye farther north closer to the CWA.
The aforementioned cut-off low looks to eventually near the CWA
by the weekend. Another round of high elevation accumulating
snowfall is certainly possible as a result of this system.
Lower elevations, mainly across western WY, could see a cold
rain with the potential for a transition over to wet snow during
the overnight and early morning hours. Confidence is low at
this time regarding the timing and impacts as a result of this
system. Looking back at the previous system, its possible
impacts may be pushed back to the end of the weekend into early
next week as models may be a little too quick with the lows
track. Either way, cold Canadian air accompanies this system as
it moves across the region, which would lead to a return of
chilly daytime highs and overnight lows. Overall, this system is
still multiple days out and confidence in the exact impacts and
timing remains low at this time. A better idea of what to
expect will likely come into focus over the next few days.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1056 AM MDT Tue Oct 7 2025
VFR conditions and clear skies will persist across the region for
the next 24 hours. A few patches of fog continue to scatter out to
start the period, with the most notable being in the upper Wind
River Basin to the north of KRIW. There may be occasional FEW to SCT
decks around FL005 at KRIW for the first hour of the TAF period as
this fog scatters out, but otherwise, no impacts are expected. Winds
remain light (less than 10kts) at all terminals through the period
as well. KCPR and KRKS will start to see winds increase late in the
period, after 16Z Wednesday.
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...
None.
&&
$$
UPDATE...Myers
DISCUSSION...Dziewaltowski
AVIATION...Hensley

NWS RIW Office Area Forecast Discussion