708
FXUS65 KRIW 061021
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
421 AM MDT Sat Jul 6 2024

.KEY MESSAGES...

- Elevated to Critical fire weather conditions expected today
  across portions of central and southern Wyoming. The
  combination of low humidity and gusty west winds can be
  expected through this evening.

- Showers and a few thunderstorms will move across northern
  Wyoming this afternoon and linger into the day Sunday.

- Strong ridging brings a return to hot and dry weather next
  week.

&&

.DISCUSSION...
Issued at 209 AM MDT Sat Jul 6 2024

Northwesterly flow will continue to agitate the weather across
northern and central Wyoming today and Sunday. With dewpoints
still in the 30s and 40s east of the Divide, the next passing
shortwave will be able to tap some of this moisture to spark
showers and a a few thunderstorms this afternoon and evening.
Main focus is across the Bighorn Basin and Natrona and Johnson
Counties. Inverted-V profile indicates access to gusty winds
aloft, so some storms could be accompanied by gusty winds.
Shower activity will fade during the evening, but some lingering
shower activity is possible for central WY overnight tonight,
and will regenerate during the day Sunday. Wind field aloft on
Sunday will be much weaker, so Showers will be more isolated,
and confined to higher elevations, and downwind into
Johnson/Natrona Counties. Any precip that does fall will be
light.

On the other side of the Divide, moisture is much more lacking,
both sfc and aloft, so shower activity will not be a threat.
Instead, gusty winds translating to the sfc during the afternoon
will combine with the dry sfc atmosphere to bring an elevated to
critical fire weather threat. See Fire weather section below for
details.

Beyond Sunday, the H5 ridge centered over California will begin
to shift east, setting up across Utah by midweek. This will
push the storms track into Canada, allowing increased daily
heating across Wyoming. Temperatures will be well into the 90s
by Wednesday, and several triple-digit readings are likely by
the end of the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 414 AM MDT Sat Jul 6 2024

Wind gusts of 20 to 30 kt will return, starting at KBPI/KPNA
around 16Z/17Z, and increasing at the other terminals after 18Z.
Gusts around 35 kt will occur at KRKS. Showers and isolated
thunderstorms will develop over northern portions after 21Z,
proceeding to the southeast through the rest of the afternoon
into the evening. KCOD, KWRL and KCPR will be the likely
impacted terminals. Some of these showers could still be moving
over KCPR and approaching KRIW and KLND by 06Z Sunday.
Conditions should remain VFR, even as showers pass over these
terminals and at other terminals where skies will remain mostly
clear.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC
for the latest information on icing and turbulence forecasts.

&&

.FIRE WEATHER...
Issued at 209 AM MDT Sat Jul 6 2024

Warm temperatures today across central and southern WY will
bring very dry conditions this afternoon. Humidity levels will
be 10 to 15 percent generally south of a line from Riverton to
Casper, with the driest conditions across Sweetwater County. A
passing weather system will bring along gusty winds aloft, which
will mix down to the sfc during the afternoon. Expect frequent
gusts above 30 mph for this region during the afternoon,
decreasing around 8 PM this evening. Winds aloft turn more from
the north overnight, pulling increased moisture in from the
north. This will bring improved humidity readings for Sunday, so
fire weather threat will be decreased.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 2 PM this afternoon to 8 PM MDT this
evening for WYZ280-283.

&&

$$

DISCUSSION...Straub
AVIATION...Hattings
FIRE WEATHER...Straub