Buffalo, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

132
FXUS65 KRIW 261040
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
440 AM MDT Thu Jun 26 2025

.KEY MESSAGES...

- Warmer and drier today with only isolated thunderstorms in
  northern Wyoming. Elevated fire weather is likely in central
  and southern Wyoming.

- Elevated to critical fire weather is likely for much of the
  area on Friday afternoon.

- Above normal temperatures are expected to continue through the
  weekend into early next week.

&&

.DISCUSSION...
Issued at 249 AM MDT Thu Jun 26 2025

June is typically the most active month for severe weather
(hail, tornadoes) etc in western and central Wyoming and the
past month is no exception. Eventually, we begin to transition
into a drier time when fire weather concerns become the main
concern and while we are not completely there yet, we have
begun the slow transition.

Flat ridging will dominate the weather through around Saturday. This
typically means flow will be mainly from the west and southwest, and
will bring warmer temperatures. We will see a period of above normal
temperature through the weekend. Areas in our warmer locations, like
Greybull and Worland, will see highs climb back close to the 90s
today with 80s widespread across most of the lower elevations. We
could still see a few thunderstorms today, mainly across the
northern mountains and adjacent foothills as a shortwave brushes by
to the north. The atmosphere is much drier today though. This is the
first day in a while that precipitable water values are below
the 50th percentile. This means coverage will be isolated (at
most a 1 out of 5 chance). However, it also means dewpoint
depressions will be large so any thunderstorm or shower that
forms could have strong wind gusts of 40-50 mph. As for fire
weather concerns, humidity will be low, falling below 15 percent
in many lower elevation locations (especially across central and
southern portions). Wind should remain on the light to moderate
side, so critical fire weather is not expected.

Concerns do increase on Friday though. Another shortwave will move
by to the north. Again, isolated storms (a 1 out of 6 chance)
will be possible in the northwest but this is the main concern.
The pressure gradient will be a bit tighter. In addition, a jet
streak moving across Montana will put Wyoming in the right
front quadrant of the jet, enhancing downward momentum of 20 to
30 knot 700 millibar winds. Increased southwest flow will also
bring a hot day, with fairly widespread highs in the low to mid
90s. Humidity will be very low as well, falling into the single
digits at this time. Additionally, fuels have turned critical
in a few locations. One of these locations is Natrona County,
and this is also one of our windier locations. With this, we
have hoisted a Fire Weather Watch for Friday afternoon and
evening. Other locations could have elevated to critical fire
weather, but less wind or fuels not being critical should
prevent more widespread watches.

On Saturday, we have a few more questions. We thought about going
two days on the Watch, but have held off for now. For one, the
best jet forcing moves a bit further north, reducing downward
momentum. The result is wind should be a bit lighter. In
addition, most guidance shows a bit more moisture moving in,
raising dewpoints anywhere from 5 to 10 degrees, making things
more borderline. The increased moisture and with what forcing we
have from the right rear quadrant of the jet, thunderstorm
chances may increase a bit, but the chance is still only around
1 out of 4.

A somewhat stronger wave and associated weak cold front will swing
through the area on Sunday, taking the edge off of the heat. It will
also increase chances for showers and storms in eastern portions of
the area, where surface easterly flow may provide convective
initiation, mainly in Johnson and Natrona Counties. Ridging then
builds northward for early next week, resulting in above normal
temperatures again. Most convection these days should be in the
mountains and adjacent foothills, but any spot generally only
has a 1 in 4 chance of a shower or thunderstorm. Another wave
may bring increased showers and storms for Wednesday, but timing
this far out is uncertain.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 435 AM MDT Thu Jun 26 2025

SKC skies to be in place through 18Z-20Z, as SCT-BKN FL150-250
clouds increase over northwestern portions. Additional CU will
develop across the area through the afternoon and move to the
east-northeast. Isolated showers and thunderstorms will be
possible along and north of a KAFO-KBYG line from 20Z-05Z.
Confidence remain too low to include into any of the forecasts
for KJAC, KCOD and KWRL. Wind gusts up to 20 kt is expected at
terminals west of the Divide in the afternoon. These winds
decrease toward sunset after 00Z/01Z due to radiational cooling,
remaining light through the overnight hours. No other weather
elements are expected at this time.

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 249 AM MDT Thu Jun 26 2025

Elevated fire weather is possible this afternoon with humidity
falling below 15 percent across much of the southern half of the
area. Wind should remain light to moderate though. On Friday,
stronger wind, combined with low humidity, will lead to the
likelihood of elevated to critical fire weather across much of
the area. A Fire Weather Watch has been issued for zone 280 as a
result.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Friday afternoon through Friday
evening for WYZ280.

&&

$$

DISCUSSION...Hattings
AVIATION...LaVoie/Lowe
FIRE WEATHER...Hattings