Casper, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

871
FXUS65 KRIW 250442
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1042 PM MDT Thu Apr 24 2025

.KEY MESSAGES...

- Showers will linger through the night, generally decreasing
  in coverage.

- Shower and thunderstorm chances (20 to 40%) return for Friday
  afternoon but are expected to be mostly limited to central
  and western WY.

- A brief warm up looks to arrive for the weekend with highs
  around 10 to 15 degrees above normal values.

- Unsettled weather returns to start next week with increasing
  confidence in a potent disturbance to bring widespread chances
  (60 to 80%) for precipitation.

&&

.UPDATE...
Issued at 206 PM MDT Thu Apr 24 2025

Today telling the classic tale of the two sides of the Continental
Divide.

West of the Divide, mostly clear skies across ID and southern WY
have allowed for instability to develop and thus, thunderstorms have
started to develop fairly widespread across those areas, as
expected. Notably, a line of storms from the UT/ID state line into
Jackson Hole has continued to ramp up over the past hour (since
1300L). Lightning, small hail, along with wind gusts up to 30
mph have been observed along that line, however, storms
generally are weakening as they tangle with the western WY
mountains. This line is certainly worth monitoring through the
evening, however as it continues to track eastward into WY.

East of the Divide, it has been dreary and cool, with highs
topping off later this afternoon in the mid to upper 40s, a good 10
degrees below normal. Low clouds will generally continue to linger
through at least Friday afternoon as upslope NNE flow continues.
This will inhibit instability and convective development.
Regarding precipitation, areas east of the Divide would get the
"leftovers" of the convection from west of the Divide as it
crosses the Divide later this afternoon and evening. Given lack
of instability, precip will be more showery in nature with much
fewer chances for thunderstorms.

Friday will see a similar trend regarding convection, given
that low clouds will still persist east of the Divide with
clearer conditions west of the Divide. Thus, Friday could be
nearly a repeat of today, the difference being that there will
be less upper-level support for convective development, so
showers will be more isolated in nature.

&&

.DISCUSSION...
Issued at 252 AM MDT Thu Apr 24 2025

Another day of showers and thunderstorms across the Cowboy State.
Temperatures will be on the cooler side Thursday as a result of the
scattered precipitation. Highs will range from the mid 40s to low
50s with the warmest temperatures across southern WY where clouds
may briefly break up. This period of scattering clouds may allow for
some instability to develop as sunshine breaks through. Overall,
thunderstorm development is possible (15-25%) with or without brief
clearing of clouds. However, if there is a prolonged period of
clearing there may be the potential for a few strong storms
developing due to increased instability. The main concerns with any
stronger storms will be small hail, gusty winds, and frequent
lightning. The remainder of the state will see scattered periods of
showers with an isolated thunderstorm or two possible.

Chances for showers and thunderstorms continue into Friday as a weak
shortwave brushes by the state. Shower coverage will be more limited
compared to the previous days with the best chances (30-50%) for
showers being across western and central WY. Precipitation
dissipates by the evening and skies gradually clear overnight.
Saturday is looking quite pleasant with warming temperatures
currently forecasted to range from the low 70s to mid 60s. There may
be some concern for elevated fire weather conditions on Saturday and
Sunday due to these warm temperatures, low RH values, and breezy
winds. However, it does not look too be concerning at the moment as
conditions are only marginal at this time.

The end of the weekend, into the start of next week will see a
potent disturbance move over the western CONUS. Models show a low
develop and gradually track into the region. This system looks to
remain on the warmer side which would likely keep low elevations too
warm for snow and higher elevation mountains seeing periods of wet
snow. Currently, this system does look to provide widespread chances
for precipitation with the best chances being across central and
northern WY. However, there is still a lot of uncertainty regarding
this track and development of this system so things are not yet set
in stone. Overall, the active unsettled weather persists through the
remainder of the week, with a brief warm up for a portion of the
weekend before another round of wide spread precipitation takes aim
at the state.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1033 PM MDT Thu Apr 24 2025

Showers continue across central WY at KLND/KRIW/KCPR, but
showers should be ending in the next 2 to 3 hours. Cloud cover
east of the Divide will be lowering again overnight, with most
areas generally MVFR through sunrise. West of the divide will
see higher cigs above VFR, but low cigs will try to move back in
the the KRKS vicinity just before sunrise. Low clouds continue
through most of the day Friday for KLND/KRIW/KCPR and northward
into KBYG, with mainly high clouds only for remaining sites.
Another round of showers still expected around 00Z/26 at KJAC,
and may briefly influence the vicinity of KBPI/KPNA. Went ahead
with predominant shra at these sites by 00Z, with a tempo group
beforehand at KJAC if showers move in earlier. All showers here
should be finished by 06Z/26.

&&

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

&&

$$

UPDATE...Hensley
DISCUSSION...Dziewaltowski
AVIATION...Straub