558
FXUS65 KRIW 181719
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1119 AM MDT Thu Jul 18 2024

.KEY MESSAGES...

- The copy paste weather pattern continues with seasonal temperatures
  and afternoon showers and thunderstorms.

- Widespread showers and thunderstorms are looking possible for Friday
  and Saturday with many seeing chances for some much needed
  rain.

- Warmer and drier weather looks to move into the region for the start
  of next week.

&&

.DISCUSSION...
Issued at 248 AM MDT Thu Jul 18 2024

Heading into the end of the week it may start to feel like each day
is being copied and pasted for many, as each day this week has seen
very similar weather. Today will continue that trend as temperatures
remain seasonable with afternoon showers and thunderstorms. Highs
today will range from the mid to upper 80s across most of the state.
Parts of the Bighorn Basin may see warmer temperatures near the mid
90s. Slightly hazy skies are expected to linger as well due to
nearby wildfire smoke being blown into the region.

High pressure continues to shift west today, gradually making its
way toward the Desert Southwest. This high looks to stay south of
the region but will continue to funnel moisture into the area,
greatly influencing daily diurnal convection. PWAT values are
forecast to hover around 0.75" for today but some models hint at a
more sufficient push of moisture for Friday and Saturday. At the
same time, this flow will continue to push wildfire smoke in from
the PACNW over the Cowboy State. While the concentration of smoke is
not expected to create impacts, hazy skies are expected to continue
through the remainder of the week. Today, convection looks to be
widely scattered across the state, with the best chances for showers
and thunderstorms arriving later in the afternoon/evening. This is
largely due to a weak shortwave that will clip the northern border
of the CWA. Overall, chances for precipitation today range from 15-
40% with the best chances being in the northern half of the state.
Gusty outflows of 40+ mph will continue to be possible from these
storms, based off dewpoint depressions.

As mentioned before Friday and Saturday will see a more prolific
surge of moisture move into the state. PWAT values currently look to
near 1" especially east of the Divide during this time. Temperatures
are expected to be nearly identical to today with highs in the mid
to upper 80s with warmer values in parts of the Bighorn Basin.
Diurnal convection will again develop both days with scattered to
widespread showers and thunderstorms possible. There looks to be two
main concerns from developing storms for both of these days. The
first is strong gusty outflow winds as storms begin developing with
gusts of 40+ mph possible. The other concern will be brief periods
of heavy rain due to the supple moisture being advected into the
region along with the relatively slow storm motion. Overall,
precipitation chances currently sit around (20-40%) for much of the
CWA on both Friday and Saturday. If this does actually come to
fruition many areas could see some much needed rainfall, so fingers
will remain crossed.

The end of the weekend will see a gradual shift in the weather
pattern. Warm and dry weather is looking more likely as a elongated
ridge sets up to our west and slowly pushes east. This would favor
warmer and drier weather for the start of next week as the ridge
gradually moves east. Afternoon showers and thunderstorms are still
possible but are looking more unlikely and isolated in nature
compared to the past few days. Above normal temperatures are
possible by the middle of next week as the ridge axis finally pushes
across the region. A lot of uncertainty remains for the upcoming
week, as models hint at a potent low moving into the PACNW. This
disturbance looks to possibly usher in another weather pattern with
a greater chance for cooler and wetter weather.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1118 AM MDT Thu Jul 18 2024

Similar to the past few days, today sees shower and thunderstorm
chances this afternoon and evening. They look to remain isolated, so
difficult to determine if a storm will exactly hit a terminal. TEMPO
groups have been included at most TAF sites to account for
thunderstorm chances and associated outflow wind gusts. Gusts could
be as high as about 40 knots. Showers/thunderstorms decrease with
sunset and most should be done by 06Z, though a few showers may
still be lingering a few hours longer. Dry conditions start Friday
morning, with showers and thunderstorms once again possible for late
morning and afternoon.

Smoke continues across portions of the area, but no impacts to
ground visibility are expected at this time. Some mountain
obscuration continues.

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.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...Wittmann