055
FXUS65 KRIW 032039
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
239 PM MDT Thu Jul 3 2025

.KEY MESSAGES...

- Widespread showers and thunderstorms with the main concern
  being heavy downpours and gusty winds continue through the
  rest of the afternoon and evening.

- Friday will see another round of showers and thunderstorms
  with activity more spotty in nature later in the afternoon and
  evening.

- Quieter conditions are expected for the weekend with some
  isolated showers and thunderstorms possible, especially
  Saturday.

- Hot and drier weather looks to return for next week with
  elevated fire weather conditions possible.

&&

.UPDATE...
Issued at 235 PM MDT Thu Jul 3 2025

Showers have continued to be widespread across the region, as
expected. CAMs have been fairly inconsistent with timing and
intensity of shower and thunderstorm activity today. The weaker
reflectivity returns on radar have been generally just virga, as it
seems as though the moisture surge has struggled to saturate the
full column and there is still enough low-level dry air around that
precipitation amounts are generally lower than expected. This should
change with the secondary wave of showers and thunderstorms later
this evening, and I would expect to see more locations to get rain
this evening and overnight. Also, notably, convection has been
suppressed for the most part. This is in response to significant
high cloud cover that has persisted through much of the day across
the region. In areas where this cloud cover has been more scattered,
including eastern portions of the Wind River Basin into Natrona and
Johnson Counties and eastern Sweetwater County, showers and
thunderstorms have been more convective in nature. A slight sliver
of the Marginal Risk for severe weather that is in place across
northeast WY now extends into northeast Johnson County, where the
better instability exists.

Overall, several rounds of showers and storms are still looking
likely through the rest of today and again Friday. For those with
4th of July plans, it is not looking like a complete washout, but
there will be several rounds of showers and thunderstorms that could
impact your BBQs and fireworks. Generally, the first round looks to
move into western WY around noon or shortly before, pushing east of
the Divide by 1300 or 1400. Chances then continue off and on through
around 2200 to 2300 Friday night, with chances varying depending on
where you are located and what model you look at.

&&

.DISCUSSION...
Issued at 221 AM MDT Thu Jul 3 2025

Warm well above normal temperatures along with widespread showers
and thunderstorms enveloped the Cowboy State on Wednesday. Thursday
will see much of the same with a few exceptions, one being cooler
more seasonable temperatures and the other being an influx of
moisture. Temperatures for today will range in the mid 70s west of
the Divide and mid 80s to low 90s east of the Divide. As mentioned
earlier an influx of moisture will make its way into the region.
PWATs are expected to near 1 inch translating to almost 200% above
normal values. This will increase the chances for periods of heavy
downpours as showers and thunderstorms develop and move across the
state during the afternoon and evening. Storms will have the
potential to produce localized flash flooding especially in poor
drainage areas and susceptible urban areas. The other concern that
develops on Thursday will be increased chances for strong
thunderstorms. These increased chances are due to higher CAPE values
along with more favorable dynamics as a result of a shortwave trough
moving across the region. The best chances will be across central
and northern WY with the main hazards being small hail and strong
gusty outflow winds. Showers and thunderstorms will linger into the
late evening and early Friday morning before dissipating later in
the morning.

Looking towards Friday, the 4th of July, unsettled weather looks to
be likely. Temperatures will cooler compared to earlier this week,
returning to near seasonable values. Above normal PWATs linger which
would create another day with chances for heavy downpours. Models
show another shortwave move across the region with short range
models coming into fairly good agreement regarding impacts and
timing. Models indicate the best chances for showers and
thunderstorms being across central and northern WY. The remainder of
the state will have lesser chances for showers and thunderstorms but
cannot be completely ruled out. A brief period of clearing during
the morning and early afternoon may produce sufficient
instability to fuel some stronger thunderstorm development.
Along with this instability, more favorable dynamics will be in
place as this shortwave moves across the area. The best chances
for strong thunderstorm development looks to be across portions
of northern and eastern WY. The main hazards for Friday will be
small hail, strong outflow winds, and heavy downpours capable of
localized flash flooding especially in poor drainage areas. All
this information does make it seem like the day may be a
complete washout. However, convection is looking to dissipate
gradually during the evening and possibly by sunset. A few
isolated showers may be lingering after sunset but as a whole
activity should be dying down in time for 4th of July events.

The weekend is looking less active but will still have some chances
for showers and thunderstorms. Coverage of these showers and
thunderstorms will be less widespread with much of the state
remaining dry. Temperatures will be seasonable but begin to
gradually warm as ridging looks to start building in over the
western CONUS. A period of hot and dry conditions is beginning to
look more likely for the upcoming week. A big factor will be the
strength of the ridging and how long it can prevail over the region.
There is still time for things to change but as of right now the
July heat and dryness looks to be right around the corner. This
may lead to some elevated fire weather conditions so it will
need to be monitored as we head into the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1110 AM MDT Thu Jul 3 2025

A difficult TAF forecast. Moisture will be moving in from the south
today. In combination with afternoon heating and shortwave activity,
showers and thunderstorms are possible through much of the period
for all sites. For this afternoon, chances are 20% to 40% starting
roughly 18z. A shortwave keeps shower chances going even after this
evening, lasting longest (until about 12z) further east at KCPR.
PROB30 groups have been used for all sites through this afternoon
for thunderstorm chances, which could bring brief visibility drops
and gusty winds 30 to 40 mph. It will likely be a "hit-or-miss" kind
of day on whether or not a thunderstorm moves directly over a
terminal.

With chances continuing tonight, PROB30 groups have been included at
some sites for the rain shower chances. Chances generally decrease
from west to east. Thunderstorm chances again increase Friday
afternoon.

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

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Hensley
DISCUSSION...Dziewaltowski
AVIATION...Wittmann