Point Of Rocks, Wyoming Weather Forecast Discussion

608
FXUS65 KRIW 071550
AFDRIW
Area Forecast Discussion
National Weather Service Riverton WY
950 AM MDT Sun Sep 7 2025
.KEY MESSAGES...
- Isolated to scattered showers and thunderstorms develop
  between 1 and 2 PM Sunday and persist through much of Sunday
  evening. Locally heavy rain and wind gusts 35 to 45 mph will
  be possible with the stronger (10% chance) storms, mainly
  along and west of the Continental Divide.
- Widespread elevated fire weather conditions are expected Monday
  through Thursday, with a focus on Wednesday and Thursday.
  Gusty southwest wind 20 to 35 mph is the primary hazard,
  mainly in southwest and central Wyoming.
- Afternoon and evening showers and thunderstorms are expected
  again Tuesday through Friday, with chances for widespread
  precipitation across the far west beginning Friday.
&&
.DISCUSSION...
Issued at 140 AM MDT Fri Sep 5 2025
A broad ridge will be over the Cowboy State today, with subtle
embedded shortwaves moving in from the southwest. These will provide
the necessary lift for more widespread shower and thunderstorm
activity across the CWA this afternoon and evening. High
temperatures this afternoon will be in the upper 70s to upper 80s,
with Johnson County being 10 degrees warmer. Thunderstorms are not
expected to be strong again today, but locally heavy rain could
occur as PWATs increase to around 0.6" to 0.85". This will translate
to dewpoints in the upper 30s to upper 40s across the forecast
area. This will be a 20 degree increase from Saturday for areas
east of the Divide. Additionally, MLCAPE values of 200-500 J/kg
will be in place. The one exception looks to be around the Star
Valley, where MLCAPE values around 1000 J/kg could occur. Any
areas of upper level diffluence are a bit isolated, but one area
looks to coincide over the Alpine-Bondurant area. As such, the
steering flow will remain light so the showers and storms will
be slow moving. This would add to the threat for locally heavy
rain. Wind gusts up to 30 mph are expected by mid to late
afternoon, with higher gusts of 35 to 45 mph occurring with any
outflow boundaries. Higher gusts up to 55 mph will not be out
of the question. The smoky/hazy conditions should begin to
improve from southwest to northeast due to the change in the
upper level flow pattern, as well as an increase in
moisture/clouds and mixing of the atmosphere from the showers
and storms. The exception looks to be Johnson County, which
will see an increase in the smoke as it gets pushed into this
area through the afternoon.
Conditions look to remain mostly dry Monday, as the ridge
reestablishes itself over the WY/ID border. Temperatures will be in
the upper 70s to upper 80s again, with drier air returning. This
will lead to elevated fire weather conditions across much of the
CWA. Wind gusts of 20 to 25 mph will occur by mid to late afternoon
for most locations. Any precipitation looks to be very isolated over
far southern portions of Sweetwater and Natrona counties.
Chances for precipitation do not look to be as widespread as
previously thought for Tuesday. A shortwave trough is still progged
to move over the Cowboy State, with diffluent flow occurring over
northwestern portions. Precipitation chances look to be in this
area, as well as Natrona/Johnson counties as the trough moves over
eastern WY. The upper level low will be stationary over the
PACNW Wednesday, allowing for additional shortwaves to move
through a southwest flow pattern aloft over the CWA. Isolated to
scattered showers and thunderstorms will remain possible, but
no signal for a widespread precipitation event. Similar
conditions look to return for Thursday, as the low begins to dig
southward over northern CA. This could lead to more widespread
precipitation, as the channel just around the low provides
better upper level diffluence. Precipitation chances are looking
good for western portions Friday, as the eastern periphery of
the upper low moves over this area. Temperatures will remain
largely unchanged during this time, with highs in the middle 70s
west of the Divide and middle to upper 80s east of the Divide.
Fire weather conditions will remain elevated, with attention
turning to Wednesday and Thursday as a result of the southwest
winds.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 509 AM MDT Sun Sep 7 2025
Smoke lingers across some terminals to start the TAF period.
However, all terminals are still expected to remain VFR through much
of the period. A shortwave moves across the state today, which will
bring chances for afternoon showers and thunderstorms to some
terminals. The best chances will be mainly across western terminals
such as KJAC, KPNA, KBPI, and KRKS. KCOD should also have a good
chance around 30% for a brief showers or thunderstorm. Convection is
forecast to start developing around 21Z Sunday which is around the
same time PROB 30 groups begin at these terminals. Winds across all
terminals are expected to see an increase from the west/northwest
around this time. Prevailing winds of 10 to 15 knots with periodic
gusts near 20 knots will be possible. Stronger outflow gusts of 30
to 40 knots cannot be ruled out nearby any developing showers or
thunderstorms. A few terminals do have TEMPO groups to show the best
time period for the gusty winds to occur. Terminals east of the
Divide will have a small chance for a shower during the evening on
Sunday with chances around 10 to 20%. Precipitation chances begin to
decrease after 03Z Monday with clouds gradually breaking
through the end of the TAF period. Some periods of mountain
obscuration may be possible during the afternoon and evening as
showers and thunderstorms develop.
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...
Air Quality Alert until 1 PM MDT this afternoon for WYZ001-002-
012>019-023>030.
&&
$$
DISCUSSION...LaVoie
AVIATION...Dziewaltowski

NWS RIW Office Area Forecast Discussion