Grover, Wyoming Weather Forecast Discussion

791
FXUS65 KRIW 150342
AFDRIW
Area Forecast Discussion
National Weather Service Riverton WY
942 PM MDT Sun Sep 14 2025
.KEY MESSAGES...
- Unsettled conditions return early Monday and continue through
  the early half of the week with shower and thunderstorm
  chances.
- Morning lows will continue to trend seasonably downward.
  Temperatures across basins west of the Divide may approach or
  drop below freezing Monday night and Tuesday night.
- A return to warmer and drier conditions is favored to end the
  week into next weekend.
&&
.UPDATE...
Issued at 1128 AM MDT Sun Sep 14 2025
The forecast is on track today, with notably clearer conditions as
the previous wave departs to the east. Brief ridging has taken over
and will keep dry conditions through the daylight hours. The next
disturbance is evident over Oregon/Idaho and will approach this
evening. Model guidance continues to show showers arriving
overnight, moving north and east through Monday. Along with
convection, Monday will also see gusty west to southwest winds from
Uinta County through Natrona County as a surface low develops to our
northeast. Showers and thunderstorms will end for most Monday
evening, lingering later across northern Wyoming as the associated
midlevel low approaches.
&&
.DISCUSSION...
Issued at 209 AM MDT Sun Sep 14 2025
The broad trough continues to slowly try to shift east, with
multiple embedded impulses rotating through it. The latest wave
is sweeping into western Nebraska/South Dakota this morning,
with some wraparound precip trying to form back into Natrona
County. This precip has been very light, if reaching the ground
at all, and will quickly exit back to the east by midmorning.
The gap between systems today will allow most areas to see
partly to mostly sunny skies and warm temperatures back into the
70s and lower 80s.
WV imagery shows the next weather system currently coming ashore
across Oregon. This system will come rotating around the bottom
of the trough and into western WY late tonight, spreading the
next round of showers and thunderstorms into the region. Models
continue to bring this trough eastward, then stalling it across
western WY through Tuesday. This will continue the high
likelihood of showers and thunderstorms into Tuesday. With the
overarching trough nudging eastward as this arrives, the
remaining portion of the smaller system then shunts southward
late Tuesday and Tuesday night. This also brings modest
northerly flow behind it, bringing slightly cooler air into the
state. Temperatures will cool enough to approach near freezing
west of the divide in lower valleys and basins Tuesday night.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 937 PM MDT Sun Sep 14 2025
A weather system approaching from the west begins its push into
western Wyoming early in the TAF period. The initial push begins at
KJAC with a 30% chance showers between 06Z-08Z, and pushes east to
all other terminals through Monday morning. With this initial push,
rain showers are anticipated. Where confidence in exact timing
and location with the initial push is around 30%, PROB30 groups
reflect the rain chances. Gusty winds are possible with rain
showers, especially at KCOD, KLND, and KRIW. After 18Z, a
secondary push of thunderstorms is possible (around 20-30%
chance) during the Monday afternoon hours with gusty outflows
possible with any thunderstorms. Conditions are expected to stay
VFR with showers or thunderstorms; however, a brief period of
MVFR flight conditions cannot be ruled out in a heavy shower or
thunderstorm.
Outside of convection, gusty winds are forecast to increase between
15Z and 18Z at all terminals except KCOD and KWRL and continue until
03Z at the latest. Gusts around 30kts are most likely at KCPR and
KRKS.
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.
&&
$$
UPDATE...Myers
DISCUSSION...Straub
AVIATION...Gerhardt

NWS RIW Office Area Forecast Discussion