329
FXUS65 KRIW 170918
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
318 AM MDT Wed Jul 17 2024

.KEY MESSAGES...

- Another day of seasonable temperatures with afternoon showers
  and thunderstorms.

- Slightly above normal temperatures are expected to end the
  week along with daily chances for afternoon showers and
  thunderstorms.

- Hazy and smokey skies may be a continuous occurrence as flow
  remains from the NW/N and more wildfires develop to our west
  and north.

&&

.DISCUSSION...
Issued at 317 AM MDT Wed Jul 17 2024

Warm but seasonable temperatures continue across the state today.
Highs range from the low to upper 80s with the warmest temperatures
in the Bighorn Basin as highs near the mid 90s. Showers and
thunderstorms develop once again this afternoon with the best
chances remaining over central and northern portions of the CWA.
Strong outflow winds of 40+ mph will again be the main threat.
Slightly above normal temperatures are expected for the later half
of the week. Highs will range from the mid to upper 80s west of the
Divide and low to mid 90s east of the Divide. Daily chances for
afternoon showers and thunderstorms look to continue into the
weekend.

High pressure continues to sink southwest 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 inches through the remainder of the
week due to this moisture. 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 remain across the upper two-thirds
of the CWA, as the moisture and instability will be greatest here.
Per usual the best chance for a strong thunderstorm is forecast to
be over parts of Johnson County. This will be due to a east-
southeast wind advecting in Gulf moisture. Overall, chances for
precipitation today range from 20-45% with lower chances in parts of
Lincoln, Sweetwater, and Sublette Counties. Thunderstorms will be
possible across much of the same areas with most seeing a chance (15-
30%) this afternoon and evening. Gusty outflows of 40+ mph will
continue to be possible from these storms, based off dewpoint
depressions. Showers and thunderstorms will mostly dissipate by
sunset, but a few weak lingering showers and storms may be possible
into the early morning hours of Thursday.

Temperatures will be about 5 degrees warmer across the CWA Thursday,
as the high shifts eastward. Thunderstorms will develop between 20Z
and 21Z as a result of a capping inversion. This convection looks to
be more widely scattered across the forecast area, with the better
chances occurring over the northern half. Strong outflow winds will
once again be the main threat.

By the end of the week, the high will have made its way into the
Great Basin, shifting the upper level flow from northwesterly to
northerly. This shift will likely improve the wildfire smoke being
blow in from parts of the PACNW. However, there are some large fires
beginning to develop to the north so while the flow may shift
keeping western smoke away, smoke from northern fires may begin to
blow into the state instead. Highs will be hot, but still
seasonable. There will be greater chances for areas west of the
Divide to be the hotter side, due to the aforementioned northerly
winds occurring over areas east of the Divide. Diurnal convection
will continue to be possible heading into the weekend as long as the
high keeps funneling moisture into the region. Unfortunately, that
moisture is forecast to start drying up as we reach the end of the
weekend and into the start of next week. The end of the weekend into
the start of the next work week is looking messy at this point with
a lot of uncertainty. This is largely due to multiple large-scale
features interacting with each other. Models currently show the high
to our southwest remaining stationary over the Great Basin as an
upper low sits over the Central Plains. At the same time, a strong
upper-level low looks to try and make its way into the PACNW. The
current forecast is looking like the high will be pushed even
farther south as this next disturbance moves into the region
sometime next week. This would possibly mean another week of
unsettled weather, due to the influx of additional Pacific
moisture.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 931 PM MDT Tue Jul 16 2024

Showers and thunderstorms should diminish through 08Z. TAF
sites will generally remain VFR unless directly impacted by
storms, which would bring them to MVFR conditions. Skies are
more clear over KCOD/KWRL with northerly flow. Smoke is
increasing in the area reducing broad visibilities, but not yet
impacting visibility at the terminals. A couple of forecast
models are indicating an area of light showers early Wednesday
morning over northwest WY, possibly bringing some rain to KCOD
around sunrise.

The high pressure axis shifts slightly eastward on Wednesday which
should bring showers and thunderstorms to areas along and east of
the divide. SW WY should remain mostly dry, though can`t rule out an
isolated storm or two, but not confident enough to include in
the TAFs. WNW winds will continue over SW WY, while east of the
divide will see NE to E winds Wed afternoon, with stronger ENE
winds pushing southwestward into KRKS Wed evening. Most
convection on Wednesday should end shortly after sunset.

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...Hattings