010
FXUS65 KRIW 101109
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
509 AM MDT Sun Aug 10 2025

.KEY MESSAGES...

- Isolated thunderstorms in Natrona and Johnson County this
  afternoon, otherwise dry and pleasantly warm today with less
  wind.

- Fire weather concerns return for Wednesday and Thursday.

- Near normal temperatures expected Monday and Tuesday, with hot
  temperatures expected Wednesday and Thursday.

&&

.DISCUSSION...
Issued at 224 AM MDT Sun Aug 10 2025

Things are largely quiet on this 2nd sunday of August. A weak
mid level disturbance is producing a few blips on the radar
across the Wyoming - Montana border but these are producing
only a few sprinkles and should be on by shortly after sunrise.
Otherwise, it looks like a nice day for most with comfortably
warm temperatures and a sunny to partly cloudy sky. The only
exception is across portions of Natrona and Johnson County where
a subtle shortwave and maybe just enough mid level moisture may
bring isolated showers or thunderstorms this afternoon
(generally a 1 out of 6 chance). Most places won`t see one
though. And most importantly, a light to moderate wind across
most of the area so this is the first day in a while we have not
had any fire weather concerns.

No concerns on Monday as ridging will control the weather, bring
dry conditions and light to moderate wind. Temperatures will
warm through, but only to near to slight above normal. On
Tuesday, models have slowed the progression of the next front.
This should lead to lighter wind and as a result; fire weather
looks like less of a concern. A very weak shortwave may brush by
far northwestern Wyoming and could bring an evening shower or
thunderstorm, but the chance only looks like about 1 in 10 at
this time and we kept the forecast dry for now.

Concerns begin to ramp up again on Wednesday as the front moves
closer to the area. This will tighten up the pressure gradient and
turn flow to the southwest. This means stronger wind across portions
of the area, especially the southwestern Wind Corridor from Rock
Springs through Casper. This will also warm temperatures
significantly, the widespread highs in the 90s, possibly the upper
90s, in areas East of the Divide. Humidity will be low enough for
critical fire weather, but wind still looks borderline in some
locations. Enough mid level moisture may return to western Wyoming
for isolated thunderstorms, but the chance is generally less than 1
out of 5 and most locations should not see one. The most concerning
day for fire weather looks to be Thursday as the front and shortwave
approach, bringing the breeziest conditions. Convection may be a bit
more this day, but with the lack of low level moisture coverage
stills looks rather sparse at this time. Somewhat cooler
temperatures should return for Friday and Saturday, but temperatures
will still be near to lightly above average across the area.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 508 AM MDT Sun Aug 10 2025

VFR conditions prevail across all terminals throughout the TAF
period. Mid to high level cirrus may linger across some terminals
this morning but will gradually dissipate through the morning. Some
fair weather cumulus may develop this afternoon and gradually spread
east. Winds are expected to remain light ranging from 5 to 10 knots
with an occasion gust near 15 knots possible at times. A few
isolated virga showers may form nearby KCPR but models show these
being very sparse and likely missing the terminal. So at this time
any vicinity or PROB groups will be kept out of the TAF. Clouds
should dissipate in the late evening with many terminals seeing
SKC by the end of the TAF period.

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...Hattings
AVIATION...Dziewaltowski