770
FXUS65 KRIW 140446
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1046 PM MDT Fri Sep 13 2024

.KEY MESSAGES...

- Warmer and drier conditions through Saturday with little
precipitation expected.

- Dry and gusty conditions will lead to critical fire weather
conditions across portions of central Wyoming Saturday afternoon.

- Precipitation chances increase Sunday across the west, then
everywhere Monday and Tuesday as a system approaches.

- An active pattern is favored through next week which may lead to
cooler and wetter conditions.

&&

.DISCUSSION...
Issued at 203 PM MDT Fri Sep 13 2024

Today is a weather transition day behind yesterday`s low and
associated cold front. Temperatures will peak 4 to 8 degrees below
normal, with skies remaining mostly clear. The only exception may be
across the northwestern mountains where an isolated shower may pop
up within the westerly flow there.

Warmer and drier conditions will continue on Saturday as a near
zonal west flow sets up over Wyoming. Near to above normal high
temperatures will return, generally peaking in the 70s or low 80s
across lower elevations. Skies will remain mostly clear with only a
low chance of an isolated shower or two across far northern Wyoming.
One weather concern we will have Saturday is fire weather as a
fairly weak surface low develops across eastern Wyoming. In
response, this will make for a gusty (but not unusual) day across
portions of central Wyoming. We will be upgrading to a Red Flag
Warning for a few fire zones given the wind and low humidity
expected there.

By Sunday the predominant flow becomes southwesterly as a low
pressure system begins pushing into the Pacific Northwest. This will
advect even warmer air into the area, bringing highs 5 to 10 degrees
above normal. This will also return more moisture to the area;
isolated showers are possible in the afternoon across the western
third of the area (PoPs generally <20 percent). East of the Divide
will remain dry, and additional fire weather highlights may need to
be considered if the southwesterly wind continues to trend up.
Precipitation chances will increase Sunday evening, still mostly
limited to western Wyoming.

Southerly flow will take over Monday and Tuesday as the previously
mentioned low drops south and then approaches Wyoming. This will
spread precipitation chances eastward through Tuesday, though
once again most focused on western Wyoming as the low stays
centered over Idaho as it pulls north. Temperatures are looking
cooler on Tuesday as a cold front sweeps across the area.

Further ahead, guidance continues to favor another system swinging
through by Wednesday or Thursday. As it stands now this would track
a little farther east than the previous system with the low
passing right over Wyoming. Though solutions remain uncertain,
this would favor cooler than normal temperatures and a better
chance for a widespread wetting rain in the latter half of the
week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1046 PM MDT Fri Sep 13 2024

Prevailing VFR conditions to persist through the TAF period as the
region remains in between weather systems through Saturday. Wind
will be the only weather hazard, but will not be very strong for
most terminals, with gusts of 10-20 knots Saturday afternoon. The
exception is KCPR where wind will be around 15 knots, with gusts of
20-30 knots, Saturday afternoon. Skies will be mostly clear for the
next 24 hours.

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

&&

.FIRE WEATHER...
Issued at 203 PM MDT Fri Sep 13 2024

A building surface pressure gradient will lead to elevated to
critical fire weather conditions Saturday afternoon across much of
central and southern Wyoming. The Fire Weather Watch will be
upgraded to a Red Flag Warning where the wind and low humidity
align. Sunday is also looking dry and gusty as steering flow becomes
southwesterly. Additional fire weather highlights may be needed
again for portions of central Wyoming, though humidity remaining
slightly elevated may keep the concern fairly limited.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 7 PM MDT Saturday for WYZ280-289-
300.

&&

$$

DISCUSSION...Myers
AVIATION...Rowe
FIRE WEATHER...Myers