706
FXUS65 KRIW 170354
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
954 PM MDT Thu May 16 2024

.KEY MESSAGES...

- Elevated fire weather danger Friday afternoon and evening,
  with warm temperatures and wind gusts in the 40 to 50 mph
  range.

- Another windy day Sunday, with elevated fire weather concerns.

- An active weather pattern will be in place next week, with
  Thursday currently looking like the timeframe with the highest
  chances for widespread soaking rains and mountain snow.

&&

.DISCUSSION...
Issued at 250 PM MDT Thu May 16 2024

Westerly flow dominates across the region this afternoon and
evening, with temperatures about 10 degrees above average and
mostly clear skies, save for some high cirrus.

Friday will bring even warmer conditions about 15 degrees above
normal, along with elevated fire weather danger, as a weather
system moves across Montana and pushes a weak cold front across
Wyoming. Afternoon RH values will range from 10 to 20 percent,
with sustained westerly winds of 25 to 35 mph and widespread
gusts in the 40 to 50 mph range. Early afternoon through sunset
will be the period with the driest and windiest conditions.
Thankfully most areas are thoroughly in spring greenup, so fuels
are not a major concern at this time, keeping the threat of
impactful fires lower than it would be later in the summer. The
weak cold front will be mostly dry, so only isolated mountain-
based showers are likely as the front passes.

Saturday cools off a bit compared to Friday, but temperatures
remain about 5 degrees above normal, with dry conditions and
typical breezy conditions during the afternoon. Another weather
system approaches Wyoming on Sunday, tightening the pressure
gradient bringing a return of gusty afternoon winds. Relative
humidity will be in the 15 to 25 percent range, leading to a
repeat afternoon with elevated fire weather concerns. Only
scattered mountain-based precipitation is expected with this
system on Sunday.

On Monday, a reinforcing trough will bring colder air and
another chance (50% chance) for more widespread precipitation
east of the Continental Divide. Temperatures Monday cool to
about 10 degrees below seasonal normals. After a brief ridge
and drying trend mid-week, the active weather pattern continues
with a larger weather system poised to impact the region on
Thursday. This could bring another round of lower elevation
rain.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 950 PM MDT Thu May 16 2024

VFR conditions are expected to prevail through the TAF period. Skies
will remain mostly SKC, with a few periods of FEW100-200 to start
the period and during the day Friday. Winds will be the main concern
across all terminals for the late morning through the evening
Friday. Most terminals can expect to see westerly winds increase
between 15Z and 18Z with gusts around 25 knots during this time. The
strongest winds arrive by the early afternoon, with widespread gusts
of 30 to 35 knots. KCPR, KWRL, KCOD, and KRKS may see periodic gusts
near 40 knots through the afternoon hours. Light and variable winds
return to most terminals by the end of the TAF period.

A few isolated showers are possible across portions of northern and
western WY during the day Friday. Confidence is low regarding
potential impacts on any nearby terminals. KJAC, KWRL, and KCOD
would be the only terminals that may see any impacts and it
currently looks unlikely, with a (10-20%) chance of an isolated
shower.

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...Dziewaltowski