Riverton, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

399
FXUS65 KRIW 261044
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
444 AM MDT Thu Mar 26 2026

.KEY MESSAGES...

- A return to more seasonable temperatures is expected across
  much the Cowboy State today, as a cold front sweeps through.

- Showers will develop over the lower and higher elevations of
  northern WY today with a few inches of accumulating snow
  possible in the highest elevations of the northern Bighorns.

- Red Flag Warnings remain in place for southern WY through this
  evening, as a result of warm temperatures, dry conditions and
  gusty winds.

- Friday sees quieter conditions and seasonable temperatures
  with warmer temperatures returning for the weekend.

- A shift back to record warm temperatures and dry conditions
  may occur next week with early indications of a wetter and
  unsettled pattern developing.

&&

.DISCUSSION...
Issued at 247 AM MDT Thu Mar 26 2026

Scattered showers, mainly in the form of virga, are making
their way across portions of southern and central WY this
morning. Depending on how much the atmosphere can saturate,
there may be a few drops making their way to the surface early
this morning. A few rumbles of thunder cannot be ruled out as
well. These showers should mostly dissipate by around sunrise.

The record breaking heat will subside today with temperatures
cooling back down nearly 15 to 25 degrees compared to yesterday.
This is the result of a cold front that will make its way across the
state today. Forecasted temperatures will differ greatly due to the
cold front slowing down over central portions of WY. There will be a
gradient of temperatures with the coldest values remaining over
northern WY as highs only get into the upper 40s to lower 50s.
Johnson County looks to be particularly chilly, with forecasted
highs only around 40. Natrona County could be another chilly
spot with highs in the mid 40s to low 50s. The cold front looks
to slow before making its way into Fremont County. As a result,
temperatures should be able to get into the upper 50s and maybe
lower 60s depending on the timing. The warmer temperatures look
to be across southern WY, where the front wont reach until late
Thursday. This will allow for temperatures to get into the low
to mid 60s with western valleys being cooler in the low to mid
50s. Winds will once again increase with widespread gusts of 20
to 35 mph with stronger gusts nearing 40 mph likely over
southern WY. The frontal passage should limit fire weather
concerns over much of the state today. The only exception to
this will be southern WY as the late passing of the front should
allow for RH values to drop down to near or below 15%. Due to
this, Red Flag Warnings remain in effect across much of southern
WY through Thursday evening.

The other aspect of the cold front passage will be chances for
showers over portions of the lower and higher elevations of northern
WY. The timing for this precipitation will coincide with the
frontal passage. At this time, showers should begin developing
shortly after sunrise with chances increasing through the
morning and shifting east by the early afternoon. The lower
elevations with the best chances of seeing scattered showers
today will be along the Cody Foothills, eastern Bighorn Basin
and parts of Johnson/Natrona Counties. Northern Johnson County
is an area of interest as hi-res models have shown the best
chances (30-60%) for showers occurring here. Temperatures are
forecast to remain too warm for any snowfall in lower
elevations, but a brief transition to wet snow or a rain/snow
mix cannot be ruled out. Snow chances will be better across the
higher elevations of the northern Absarokas and Bighorn Ranges.
The Bighorns will have the best chances to see a light
accumulation of snow, with amounts ranging from an inch to two.
Precipitation should gradually dissipate by the evening hours
with a few lingering showers possible over Johnson and Natrona
County by sunset.

The start of next week is looking more and more interesting with
each passing day. Models are coming into good agreement that an
unsettled and wetter pattern may be on its way. However, there is
a lot of uncertainty as to where the most favorable locations
will be. So overall, next week looks to bring a much welcomed
change from the heat and dry conditions we have seen over the
past week and a half. That being said, there are no guarantees
at this moment that we will see widespread precipitation chances
but chances are slowing increasing.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 444 AM MDT Thu Mar 26 2026

A cold front continues to push southward across areas east of
the Divide this morning, with winds turning northerly in its
wake. The front is also expected to bring MVFR ceilings across
Johnson County and KCOD. Lower VFR ceilings will move in at
KCPR, persisting through the rest of the morning. Ceilings will
improve back to VFR at KCOD by 19Z. Occasional showers will be
seen across northern Wyoming through the period, though these
are not expected to impact terminals and will be mostly confined
to the mountains. Otherwise, wind will increase again at
terminals after 17Z, with widespread gusts of 20 to 35kt
through the afternoon. Wind will decrease after sunset Thursday.

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

&&

.FIRE WEATHER...
Issued at 247 AM MDT Thu Mar 26 2026

A cold front passage should limit fire weather concerns for much
of the state today. Portions of central and northern WY will see
cooler temperatures, higher humidity values and gusty winds of
20 to 35 mph. Southern WY will be the one exception to this due
to a later frontal passage timing. As a result, warm
temperatures, low RHs, and gusty winds in excess of 40 mph at
times will persist through much of the day.

&&

.CLIMATE...
Issued at 247 AM MDT Thu Mar 26 2026

The summer-like temperatures persisted across the Cowboy State on
Wednesday, leading to numerous high temperature records being
broken. High temperatures ended up climbing into the upper 70s
to low 80s east of the Divide and low to upper 70s west of the
Divide. A location of note was Rock Springs, which hit 78F
breaking the previous all-time high temperature record for
March of 76F. This previous record occurred only a few days ago
back on March 21st. An example of how anomalously warm that
value is, the high temperature record for April at Rock Springs
is 79F meaning we fell only 1 degree short of tying the record
for April while still in March. Lander is another location of
note, with records going back to 1891. The mercury reached 81F
making it the third 80 degree day so far this month. Lander,
before this year has never recorded an 80 degree day in the
month of March. It would now tie the current record for most 80
degree days in the month of April. In total all 9 of our
climate sites broke daily high temperature records Wednesday by
multiple degrees. These records will only be adding to the long
list of records that have already been broken this month.
Overall, this recent stretch of record breaking heat is very
anomalous for March and will likely be remembered for years to
come.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for WYZ277>279.

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...LaVoie/Myers
FIRE WEATHER...Dziewaltowski
CLIMATE...Dziewaltowski