966
FXUS65 KRIW 061728
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1128 AM MDT Thu Jun 6 2024

.KEY MESSAGES...

- Warm and dry conditions expected today.

- Shower chances increase tonight through the weekend, but most of
  the area remains warm and dry.

- Increased mountain snowmelt expected with minor river and stream
  flooding possible.

&&

.DISCUSSION...
Issued at 326 AM MDT Thu Jun 6 2024

After the warmest day of the year thus far for most locations,
temperatures will warm further today as ridging helps 700mb
temperatures reach 13 to 15C over the area. Nearly all lower
elevations will see highs peak in the 80s, with a handful of
locations approaching 90 this afternoon. Otherwise, it will be dry
with plenty of sunshine. Unlike Wednesday, wind will be much more
subdued today, though not calm (obviously- this is Wyoming). With a
drier airmass mixing down, relative humidity will drop to around or
below 15 percent across much of central and southern Wyoming.
Fortunately, the lighter winds will help mitigate fire weather
concerns.

A weak shortwave will squash the ridge a bit this evening,
coinciding with increasing Pacific moisture. This may lead to a few
showers moving in from Idaho overnight. We may need to increase PoPs
across western Wyoming tonight if the current CAM solutions of
showers hold. A better bet for convection will be Friday morning and
afternoon, especially across southwestern Wyoming and the higher
elevations of western Wyoming. Otherwise, Friday will be a similarly
warm day, though the added convective activity may end up keeping
temperatures a bit cooler than currently forecast.

Guidance paints a similar picture for the weekend; highs will
generally peak in the upper 70s or 80s with continued afternoon
convection. The best chances will be over the western mountains
(around 30-40 percent). There is still some models hinting at a
stronger mid-level wave clipping the area as it swings through
Idaho Sunday evening. This would bring more widespread showers
to northern and western Wyoming Sunday night.

Further out, ensemble cluster mean guidance still favors anomalously
high 500mb heights to persist through next week. This would keep
warm and mostly dry conditions across the area. Given the warm
temperatures this week and next, rivers and streams will continue to
be monitored for flooding potential as mountain snowmelt is
exacerbated.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1126 AM MDT Thu Jun 6 2024

VFR conditions expected at all TAF sites through the period. Light
winds and clear skies mainly to start the period. Winds pick up some
at BPI, RKS, and PNA after 20Z with an approaching weak system to
the northwest. Winds will diminish with radiational cooling after
around 02Z with increasing upper level clouds through the afternoon
and evening. Light winds less than 10kts for sites east of the
Divide. Dry conditions expected with no other weather elements
forecasted. The exception may be some showers approaching KJAC after
07Z but not enough confidence to include in the forecast at this
time. Increasing winds on Friday toward the end of the period, still
20 kt or less.

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

&&

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

&&

$$

DISCUSSION...Myers
AVIATION...Hattings/Swanson