283
FXUS65 KRIW 301912
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
112 PM MDT Tue Apr 30 2024

.KEY MESSAGES...

- Scattered rain/snow showers across western/northern WY during
  the afternoon and evening today.

- Other parts of the state look to remain dry, with gusty winds returning
  for the afternoon/evening.

- Light snow showers possible for western mountains and valleys Wednesday
  through Thursday.

- Another chance for precipitation to end the week, with central
  and southern WY possibly seeing light snow Friday morning.

&&

.DISCUSSION...
Issued at 109 PM MDT Tue Apr 30 2024

A cold front moved through the state last night, which was definitely
felt this morning, especially west of the Divide, where places like
Big Piney saw morning temperatures in the low 20s. East of the
Divide was slightly milder, as breezy winds lingered through the
night keeping temperatures from dropping.

Conditions look to remain mostly dry today with an upper-level low
staying north of WY. The main concern today will be near
elevated fire weather conditions, as a potent upper-level jet
crosses over the area. This will aid in mixing down strong winds
with wind prone areas seeing a (40-70%) of seeing 40+ mph
gusts. Other parts of the state likely see breezy conditions as
well, with a (30-60%) chance of seeing gusts of 30 mph. RH
values will also be rather dry with percentages around 15-20%.
Temperatures are forecast to remain cool, with highs around 5-10
degrees below normal, which will limit any rangeland fire
danger statements from being issued. Most of the state is
expected to remain mostly dry with the exception being
northwestern/northern portions of the CWA. These areas have a
(20-40%) chance of seeing a brief shower during the day Tuesday.
Other parts of the state likely remain dry but an isolated
shower cannot be ruled out.

The upper-level low that was mentioned earlier will be a key player
in the weather across the Cowboy State through the remainder of the
week. This low will continue to eject quick moving shortwaves
through the region, with the first arriving early Wednesday
morning. Impacts look to be minimal with this disturbance having
little moisture with it and the track being not very favorable
for widespread precipitation. Currently, scattered showers
develop Wednesday morning mainly across northern and western
parts of the CWA. Due to cold 700 mb temperatures of -5 to -10C
associated with this system, snow levels likely lower enough
for western valleys to see a brief period of light snow. Jackson
Hole and Star Valley look to have a (30-50%) chance of seeing
greater than 0.5 inches of snow. Western mountains look to see
1-3 inches of snow by Thursday morning. Highlights are not
expected to be issued, due to the low impacts and snow
accumulations. The remainder of the state likely remains dry
through Wednesday and Thursday, with a (10-30%) chance of seeing
a brief shower over that period.

The next chance for widespread precipitation arrives Friday. The
northern upper-level low is finally pushed east and behind it comes
a quick hitting shortwave that moves through the state. Early
indications show impacts from this system remain across the lower
half of the CWA. There does seem to be a potential for low elevation
snowfall depending on the timing of this disturbance. 700 mb
temperatures Friday morning range from -5 to -8C across this area
bringing snow levels ~5000 feet. Models are also trying to indicate
a brief period of northeasterly flow develop as this disturbance
moves through Friday morning. If this was to occur there would be
the potential for a short period of steady precipitation in
northeasterly favored areas such as the eastern Winds and Casper
Mountain. While significant impacts are not currently expected,
there would be the possibility for light snow accumulation in
places such as Lander Friday morning. However, it is important
to keep in mind that this is very likely to change, as we are
still multiple days out and there still is high uncertainty
regarding the track and timing of this system.

The first weekend of May looks to see a return to mild and quiet
weather, as brief ridging redevelops over the region. Temperatures
may even return to the upper 60s and low 70s in some areas. This
pleasant and mild weather may be short lived, as models are
beginning to indicate another disturbance make its way into the
area for the start of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1136 AM MDT Tue Apr 30 2024

Most areas remain VFR through the next 24 hours with mostly
clear skies or high cirrus. Exception being KJAC, which
continues to get light isolated snow showers. These will
continue this afternoon, but will have minimal impacts at the
airport. These showers end this evening, but another round
returns tomorrow morning. These showers are expected to spread
across the rest of the state Wednesday, but not reaching any
airports until after 18Z.

&&

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

&&

$$

DISCUSSION...Dziewaltowski
AVIATION...Straub