964
FXUS65 KRIW 141110
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
510 AM MDT Sun Jul 14 2024

.KEY MESSAGES...

- Above normal temperatures continue today.

- Isolated showers and thunderstorms will again bring the
  potential for strong outflow winds gusting 50 to 60 mph this
  afternoon and evening.

- Elevated to near-critical fire weather conditions are expected
  through this evening.

- Smoke from western US wildfires will continue to move in causing
  hazy skies at times.

- Slightly cooler temperatures and better rain chances move in for
  Monday.

&&

.DISCUSSION...
Issued at 423 AM MDT Sun Jul 14 2024

Today is the last of several consecutive days of high temperatures
peaking well above normal. The expansive area of high pressure
responsible for the heat continues to rotate to our south, now
centered over the Colorado-New Mexico border. One notable difference
for today is the increased availability of moisture which will
continue to advect in as it rotates around the high. Current
guidance suggests fairly widespread PWAT values of 0.8" to nearly 1"
later this evening. Combined with a stronger shortwave moving
through the flow, the moisture will lead to better coverage of
showers and thunderstorms today. One caveat with the high
temperature forecast is that the increased clouds and outflow
potential may end up keeping several locations a little cooler than
previous days - though only marginally.

Other than a few weak morning showers, convection will begin
developing in earnest by early afternoon across southwestern Wyoming
and then expand quickly east of the Continental Divide. Given the
increased moisture, there will be a better chance of rain reaching
the ground today. The best chance for this to happen will be across
the higher terrain of northwestern portions of the area where
dewpoints will be slightly higher (upper 30s to 40s). However, the
more widespread impact from the convection will again be strong
outflow winds gusting up to 60 mph given the still dry boundary
layer and high LCLs; we`ll still see plenty of virga showers.
Forecast soundings continue to show the classic inverted V look
for today, as well as DCAPE values over 1000 J/kg for most of
the area. Fire weather concerns continue as well given the heat,
low humidity, and outflow wind potential. Additionally, with
instability a little higher today we may see more lightning than
previous days. Smoke from western US wildfires that are flaring
up will continue to filter in as it rotates around the high,
likely making the mountains appear a little hazy.

Showers and thunderstorms will linger through the evening across
northern Wyoming and eventually come to an end overnight. However,
another round of convection is expected on Monday as the high is
flattened somewhat by a large trough to our northeast. With
increased cyclonic flow across the area and continued moisture
availability, this activity will be widespread again, with an even
better chance of rain reaching the ground given dewpoints in the 40s
for most locations. However, we`re still looking at a relatively dry
lower atmosphere. This will lead to a continued strong outflow wind
threat - though more in the 40 to 50 mph range. Otherwise,
temperatures will trend further down on Monday though still around
or just above normal.

Tuesday looks very similar, though shifting the better precipitation
chances east of the Divide. Further out, ensemble cluster guidance
continues to favor the ridge strengthening again to our south. This
would keep temperatures on the warm side and precipitation
chances a bit more limited.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 509 AM MDT Sun Jul 14 2024

VFR conditions prevail through the majority of the TAF period.
High level clouds will be increasing throughout the day. Winds will
begin to increase through the period with occasional gusts of 20-30
knots during the afternoon and evening. Mostly all terminals have
PROB30 groups for Sunday afternoon and evening. All terminals
currently have roughly 15% to 35% chance of a shower or
thunderstorm. Brief MVFR/IFR conditions are possible with any
showers or thunderstorms that move over TAF sites. Gusty outflow
winds will be a concern during the afternoon and evening. Strong
gusts of 40+ mph are possible at any terminals with nearby
developing convection. A few lingering showers are possible into the
late evening and into the early morning on Monday.

Smoke also continues over the area. VFR conditions are expected to
remain, though 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.

&&

.FIRE WEATHER...
Issued at 423 AM MDT Sun Jul 14 2024

Elevated to near-critical fire weather conditions will continue
today given the low humidity, hot temperatures, and gusty outflow
wind potential. However, we will also see a better chance of rain
reaching the ground today, and areas directly under these
isolated cells could see a wetting rain. Increased instability
will also lead to an uptick in lightning potential today. As
with previous days, outflow wind gusts could briefly reach up to
60 mph this afternoon. Humidity recovery will be better tonight
in the wake of today`s activity.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 10 PM MDT this evening for WYZ004>006-010-
011-017-018-020.

&&

$$

DISCUSSION...Myers
AVIATION...Dziewaltowski/Hattings
FIRE WEATHER...Myers