797
FXUS65 KRIW 111914
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
114 PM MDT Sun Aug 11 2024

.KEY MESSAGES...

- More widespread showers and thunderstorms are likely from
  Monday through Wednesday.

- Warmer and mostly dry conditions expected Thursday through the
  weekend.

&&

.DISCUSSION...
Issued at 113 PM MDT Sun Aug 11 2024

Brief ridging today in between disturbances will keep conditions
cool, but dry and breezy. Monday afternoon the next shortwave
embedded in the flow makes its way into Wyoming, increasing
precipitation chances once again. Due to the cooler temperatures
and limited instability, thunderstorms that develop are not
expected to be particularly strong, but strong winds and small
hail cannot be ruled out. Tuesday into Wednesday, a stronger
shortwave trough pushes through, ingesting more moisture into
the region, continuing the chances for more widespread showers
and thunderstorms. NAEFS percentiles show widespread near 90th
percentile precipitable water values across Wyoming between 0.75
to 1.00 inch.

Thursday brings drier and warmer conditions as a ridging pattern
takes back over through the weekend. Weak disturbances embedded in
the flow could kick off a few thunderstorms daily, but the
confidence is low in any widespread impacts. Thunderstorm chances
increase slightly Saturday night into Sunday as the ridge shifts
eastward, placing central and western Wyoming on the western side,
allowing some moisture to creep back in. Temperatures during this
time are expected to be in the 70s to 80s west of the divide and 80s
to low 90s east of the divide.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1115 AM MDT Sun Aug 11 2024

VFR conditions prevail through the TAF period. No showers or
thunderstorms are expected to impact any terminals this afternoon. A
few may develop over the mountains, but should be very isolated and
remain away from any sites. The closest would be for KCOD, but
chances remain under 20% through this evening. Afternoon mixing
brings gusts 15 to 30 knots for some sites, which decrease after
sunset this evening.

Models are showing rain showers moving into Wyoming, from the west,
after 09Z/Mon. There is model disagreement on exact timings and
placements, so confidence remains low on the details. Have included
PROB30 groups in many TAFs where these chances occur. Chances for
showers and thunderstorms increases after the TAF period, for Monday
afternoon.

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 325 AM MDT Sun Aug 11 2024

A combination of humidity falling into the teens and a gusty
westerly breeze will bring elevated fire weather to portions of
Sweetwater and southern Lincoln Counties today. Elsewhere,
although there will be a gusty breeze at times, relative
humidity will remain above critical levels. Showers and
thunderstorms will be more isolated today and confined mainly to
northern Wyoming. Mixing and smoke dispersal will be generally
good to excellent in the afternoon. More widespread showers and
thunderstorms return to the west tomorrow and spread across most
of the area for Tuesday.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...

&&

$$

DISCUSSION...Gross
AVIATION...Wittmann
FIRE WEATHER...Hattings