Green River, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

755
FXUS65 KRIW 150414
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1014 PM MDT Thu Aug 14 2025

.KEY MESSAGES...

- A moisture feed in southwest flow aloft will allow for
  isolated showers, and even a few thunderstorms, to persist
  Thursday night, especially across southwest Wyoming.

- Another round of showers and thunderstorms develops between 12
 PM and 2 PM Friday. Coverage becomes more widespread by late
  afternoon before tapering off around 9 PM or 10 PM Friday.

- Daily chances for showers and thunderstorms prevail through
  the weekend.

- Above normal temperatures and dry conditions are expected to
  return for much of the upcoming work week.

&&

.UPDATE...
Issued at 103 PM MDT Thu Aug 14 2025

The forecast remains mostly unchanged with widespread fire weather
concerns across the state today. Temperatures are forecast to be
slightly above normal with highs in the low 90s east of the Divide
and mid 80s west of the Divide. Showers and thunderstorms will be
possible this afternoon and evening. However, due to the overall
dryness many of these will be in the form of virga showers or dry
thunderstorms. Frequent cloud to ground lightning is expected with
any thunderstorms that develop. Dewpoints are expected to be in the
30s to 40s with temperatures in the 80s to 90s across the state this
will create depressions of nearly 40 to 50 degrees. This will lead
to the potential for strong gusty winds of 50 mph or more nearby any
developing showers or storms. Due to this SPC has put much of
central and southern WY in a marginal (1 out 5) risk for severe
winds of 58 mph or more. Red Flag Warnings remain in effect across
western, southern, and portions of central WY through this evening.
Showers and thunderstorms will linger through the late evening and
into the early morning hours on Friday.

Daily chances for showers and thunderstorms continue into the
weekend with moisture gradually increasing each day with as more
monsoonal moisture is ushered into the region. Temperatures remain
mostly unchanged through this period with seasonal to slightly above
normal values. Long range models continue to indicate a return to
dry and hot weather for next week. The current forecast is showing
temperatures returning to the mid to upper 90s east of the Divide
and low 90s west of the Divide by the middle of next week. This will
need to be monitored as the dry and warm conditions may lead to
another period of elevated to near critical fire weather
conditions.

&&

.DISCUSSION...
Issued at 146 AM MDT Thu Aug 14 2025

Though the specific details are a little different, today`s overall
forecast looks very similar to yesterday`s. Synoptically, the upper-
level ridge shifts a bit eastwards today, centered out around the
Texas Panhandle. This has two major impacts. The first is that the
pressure gradient remains fairly tight as a trough to the west moves
over Wyoming more. The other is that additional monsoonal moisture
is allowed to move up the western side of the ridge.

The focus for today remains on fire weather concerns. Yesterday was
an active day, with gusty winds (40+ mph) and frequent lightning.
Today looks like a very similar day. As moisture moves in from the
southwest, showers and storms begin to develop by late morning,
expanding over the area through the afternoon and evening. Like
yesterday, hi-res models have widespread showers/storms over the
area, though each models differs in exact details (timing/location).
Therefore, have broadly given the chances for showers/storms at any
given location at least a 15 percent chance for at least a few hours
this afternoon. Any storm will be capable of 40+ mph outflow gusts,
with the HRRR suggesting stronger storms 50+ mph. Red Flag Warnings
are in effect for much of the western and southern areas through
this evening, where dry fuels, gusty winds, low relative humidities
(RH), and thunderstorm chances best coincide. Showers will likely
linger a bit past midnight Thursday night, mainly for southwest
Wyoming.

Monsoonal moisture keeps rain chances going for Friday. There is
some concern for elevated fire weather conditions. RHs improve
slightly, but not significantly. Afternoon winds also increase
across western and southern Wyoming. Given the dry fuels and
borderline RHs, this may be another day with critical fire weather.
Confidence is a bit too low to expand the current highlights at this
time. The upper pattern changes little through the weekend, with
daily rain chances and seasonal, to a bit above seasonal,
temperatures. Long range models continue to depict the ridge
shifting back west, over Wyoming, for next week, which would favor a
return to drier and warmer weather.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1010 PM MDT Thu Aug 14 2025

Rather uncommon for summer, but isolated showers will continue
overnight. The gusty winds have largely ended, but can`t
completely rule out a gust to 20 or 30 kt overnight. Very little
precipitation is expected, but outflow winds could affect
terminals overnight.

Another weather system moves in from the south after 15/1800Z,
and thunderstorm coverage will increase notably. Most of the
state has 20 to 30 percent chances for nearby thunder, and have
used many PROB30 groups to show this threat, with timing
specified for each airport in the TAFs. The main concern Friday
afternoon will again be gusty outflow winds, which will likely
be in the 35 to 45 kt range under the stronger storms. Isolated
showers will likely again continue into the overnight.

&&

.FIRE WEATHER...
Issued at 103 PM MDT Thu Aug 14 2025

Elevated to critical fire weather conditions will persist across
much of the state today. Min RH is forecast to range from 15 to 20
percent with lower values expected for locations east of the Divide.
Winds will increase from the west/southwest this afternoon with
periodic gusts around 20 to 25 mph especially west of the Divide.
Widespread chances for showers and thunderstorms are expected
to develop this afternoon and evening. However, dry conditions
will lead to little to no chances for wetting rains. Many of
these showers and storms may develop into virga showers or dry
thunderstorms. Frequent cloud to ground lightning and strong
gusty outflow winds of 40 mph or more will be possible nearby
any developing storms. Red Flag warnings remain in effect across
western, southern, and portions of central WY through the
evening tonight.

&&

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

&&

$$

UPDATE...Dziewaltowski
DISCUSSION...Wittmann
AVIATION...VandenBoogart
FIRE WEATHER...Dziewaltowski