777
FXUS65 KRIW 041828
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1228 PM MDT Tue Jun 4 2024

.KEY MESSAGES...

- Warm and dry through Thursday. Thursday and Friday look to be
  the hottest, with high temperatures in the middle to upper
  80s for most.

- Gusty winds today and tomorrow, with elevated fire weather.

- Afternoon showers possible Friday and Saturday, but otherwise
  dry and warm conditions continue through the weekend. Minor
  flooding concerns as warm temperatures continue.

&&

.DISCUSSION...
Issued at 1227 PM MDT Tue Jun 4 2024

The low, and associated trough, that brought rain to the area
yesterday moves eastward through Canada today. At the same time, a
strong ridge begins to build in over the Southwest U.S. These two
systems keep a tight pressure gradient across Wyoming today. As a
result, widespread gusts 30 to 40 mph occur through the day.
Mountain locations continue to see gusts to around 50 mph. Winds
come down some tonight, except for the central mountains, which may
actually see some winds increase some. Otherwise, today remains dry
as high pressure begins to build in. High temperatures today peak
near, to slightly above, average.

The pressure gradient remains for Wednesday, with gusts 25 to 35 mph
for the Wind Corridor, with lesser gusts elsewhere. With relative
humidities dropping into the upper teens in the afternoon, elevated
fire weather concerns remain. High temperatures trend around 10
degrees warmer than today as high pressure continues to build in.
Winds decrease Wednesday night as the high pressure builds in and
the aforementioned low tracks eastwards.

Thursday and Friday look to be the warmest days this week. Highs in
the middle to upper 80s will be common; the warmer spots may see the
first 90s of the year. Though these temperatures are not uncommon
for Wyoming summer, they are 10 to 15 degrees above average for this
time of year, with shift of tails and other guidance showing this as
unusual heat. Being the first of this heat since winter, it is
important to be prepared if you plan on being outside this week or
weekend. With this heat, we are still monitoring river sites as
mountain snow melt occurs. Thursday/Friday would see the quickest
melt, being the warmest days, but highs are still above normal
through the weekend. Minor flooding concerns continue as a result.

Thursday looks dry. Friday and Saturday may see some afternoon
convection as some shortwaves move through with a little associated
moisture. Chances, currently, are on the order of 15% to 35%, but is
expected to change given it`s still 4 and 5 days out.

Models are projecting a bit more of a potent system come Monday.
This has the potential bring some cooler, near seasonal,
temperatures to the area and better rain chances. Looks like more
high pressure follows this system, with warmer temperatures
returning. The Climate Prediction Center (CPC) has Wyoming in
favored warmer than normal conditions in all current outlooks
(ranging from 6-10 days to 3 months).

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1130 AM MDT Tue Jun 4 2024

Yesterday`s weather system moved eastward overnight, bringing
strong northwest mid-level flow over western and central Wyoming
today. With some cumulus around 5-7K ft and high clouds
streaming toward the southeast, VFR conditions will dominate
today and remain through the forecast period at the TAF sites.
Biggest issue today is the WNW wind, with 15-25 kts and gusts
25-35/40 kts this afternoon and early evening. Far northwest WY
may see some localized MVFR conditions late this afternoon and
evening, but precipitation is not expected at any TAF sites.
Winds will decrease around sunset, but remain 8-12 kts. The WSW-
WNW winds will increase again between 05/15-17Z tomorrow as a
zonal/NW mid-level flow pattern continues with high pressure
building over the Great Basin. A weak wave in the flow will
bring increased clouds to northern WY from 05/06-18Z, with
decreasing clouds in the afternoon. Wednesday`s winds will again
be 15-25 kts with 20-30 kt gusts during the afternoon at most
TAF sites.

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

&&

.FIRE WEATHER...
Issued at 1227 PM MDT Tue Jun 4 2024

Elevated fire weather Wednesday, due to a combination of gusty winds
and dry conditions. Gusts 25 to 35 mph for the Wind Corridor of
zones 277, 278, 279, 280, and potentially 281. Relative humidities
in the mid-to-upper teens for the afternoon in those zones. Winds
decrease Wednesday night. Thursday looks drier, but lighter
wind is expected.

&&

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

&&

$$

DISCUSSION...Wittmann
AVIATION...McDonald
FIRE WEATHER...Wittmann