871
FXUS65 KRIW 140352
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
952 PM MDT Thu Jun 13 2024

.KEY MESSAGES...

- Rivers will continue to run high due to snowmelt, but most
  have already reached their highest level for the snowmelt
  season, and will be decreasing over the coming week.

- Temperatures continue to run 10 to 15 degrees above seasonal
  normals through the day Saturday. Most areas will stay dry.

- Breezy winds are expected on Saturday combined with
  temperatures well above normal, leading to elevated fire
  weather conditions.

- Temperatures begin cooling on Sunday, and below average
  temperatures are expected by Tuesday as the next weather
  system moves through.

&&

.DISCUSSION...
Issued at 250 PM MDT Thu Jun 13 2024

This evening, a shortwave trough moving across the Four Corners
region will spread enough mid-level moisture to support isolated
showers and thunderstorms for southern and central Wyoming. The
main threat with these storms will be brief gusty outflow winds
45 to 55 mph. Showers could (20 % chance) linger well into the
day Friday, as the modest supporting lift is slow to exit the
region. Gusty winds would again be the main concern with any
showers on Friday afternoon.

The region remains under the influence of a longwave ridge over
the next few days, which brings warm temperatures about 10 to
15 degrees above normal through Saturday. Sustained winds
increase slightly on Friday, but will still be relatively light
by Wyoming standards. On Saturday the winds become strong and
gusty for most locations, and this combined with the heat and
dry air in place will lead to elevated fire weather conditions.
Thankfully fuels are still relatively moist from spring green-
up.

Despite the warm temperatures and rapid high elevation snowmelt,
most rivers and streams across the region have leveled off, and
many are showing signs of slowly falling. The Bear River in
southwestern Wyoming is one exception, where peak flows look to
occur in the next week or so. The lack of widespread
precipitation through the weekend should allow most other rivers
to continue to slowly decrease their flow rates.

The next large weather system to impact the region will move in
Monday into Tuesday. A majority of the lift with this system
will be over Montana, leaving Wyoming mostly dry. The northern
Wyoming border could (20% chance) see light rainfall during
this timeframe. Other areas will stay mostly dry. Temperatures
moderate to near normals by the end of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 950 PM MDT Thu Jun 13 2024

Conditions will remain VFR through the TAF period, unless a strong
thunderstorm moves directly over a terminal Friday afternoon. If
that occurs conditions may drop to MVFR briefly with reduced VIS.
Tonight isolated rain showers and possibly a thunderstorm (15%) will
continue across southern and central portions of the area. Most
activity will subside shortly after the beginning of the TAF period.
Wind will be light (5-10 knots) through tonight.

Wind will increase Friday morning into Friday afternoon as a weak
cold front moves through the area. Gusts will be 20-25 knots on
average Friday afternoon. Scattered rain showers and thunderstorms
will develop in the afternoon as this front moves through. The best
chance for thunderstorms in the vicinity of a terminal will be at
KCOD as convection develops along the eastern slopes of the
Absarokas and moves east with the general flow. So, have included
VCTS at KCOD Friday afternoon. A lower chance for showers and storms
at KWRL for Friday afternoon, so included a PROB30 group with -TSRA.
Strong wind gusts around 40 knots will be possible (40-50%) with any
thunderstorms that develop.

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

&&

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

&&

$$

DISCUSSION...VandenBoogart
AVIATION...Rowe