466
FXUS65 KRIW 121114
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
514 AM MDT Fri Jul 12 2024

.KEY MESSAGES...

- Another day of hot temperatures.

- Isolated showers and thunderstorms may bring strong outflow winds
  gusting 50 to 60 mph this afternoon and evening.

- Elevated to near-critical fire weather conditions are expected
  through the weekend.

- Temperatures remain hot through the weekend, then cool slightly
  for early next week.

&&

.DISCUSSION...
Issued at 423 AM MDT Fri Jul 12 2024

Not a whole lot of change in the forecast today - it will be another
hot one. The strong ridge remains in place, now centered over
southern Utah. Highs will again peak into the upper 90s or lower
100s east of the Continental Divide and lower to mid 90s west.
That`s good for around 10 degrees above normal for this time of
year.

One potential difference today may be slightly increased coverage of
showers and thunderstorms this afternoon and evening. The best
chance for this activity will be across northern Wyoming owing to a
weak shortwave rotating through the flow. This area will also
benefit from higher moisture availability. Additionally, we expect
more cumulus buildup west of the Divide today, with an isolated
shower or storm possible (less than 10 percent for any one
location). In reality, most locations will remain dry across the
area, with much of the rain evaporating well before reaching
the ground given the dry boundary layer and correspondingly high
LCLs. As before, the main concern with any showers or storms
will be strong outflow wind gusting 50 to 60 mph.

With the potential for more convection and outflow, fire weather
concerns will be heightened today given the very warm and dry
(minimum humidity less than 10 percent) background environment.

The heat will continue through the weekend as the overall synoptic
pattern remains largely unchanged. Coverage of afternoon convection
will continue to trend up as monsoonal moisture is advected into
Wyoming. Again, however, the dry lower atmosphere will keep the
majority of the area rain-free with the main concern being wind
gusts.

By early next week the ridge may get flattened somewhat, which will
likely provide somewhat of a relief from the heat as well as
increased rain chances. Still, ensemble cluster guidance favors
continued anomalously high 500mb heights over the region through the
end of next week. This would keep temperatures on the warmer side
with precipitation chances limited to isolated diurnal convection.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 513 AM MDT Fri Jul 12 2024

VFR conditions will prevail through the TAF period. Wind gusts of 20
to 25 kt will return across the forecast area through the afternoon
(after 18Z). Any virga showers/thunderstorms will be isolated, with
northwestern portions having the best chances. For now, KCOD looks
to be the main terminal to be impacted by this convection. However,
stay outflow boundaries could create locally strong, erratic wind
gusts.

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 Fri Jul 12 2024

Elevated to near-critical fire weather conditions are expected
through the weekend. Humidity will drop below 10 percent for much of
the area today. Wind will be the more limiting factor for a greater
risk, though any showers or thunderstorms in the area will have the
potential to produce outflow winds gusting 50 to 60 mph. Red
Flag Warnings were considered for some of the zones that have
fully cured fuels, but confidence on persistent, widespread
gusts over 25 mph is not high enough to warrant issuance at this
time.

&&

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

&&

$$

DISCUSSION...Myers
AVIATION...LaVoie/Swanson
FIRE WEATHER...Myers