809
FXUS65 KCYS 150445
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1045 PM MDT Wed Aug 14 2024

.KEY MESSAGES...

- Scattered afternoon and evening showers and thunderstorms are
  expected today. Storms will have the potential to produce
  brief, heavy rainfall and strong gusty winds.

- Seasonable temperatures will continue through the period. Showers
  and thunderstorms will be most likely on Sunday, Monday and
  Tuesday, with dry conditions for Saturday.

- Fire weather concerns begin to increase Friday as well as
  Saturday with warmer temperatures and low afternoon humidity.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 200 PM MDT Wed Aug 14 2024

Isolated showers are beginning to pop up on radar early this
afternoon. A few isolated lightning strikes are accompanying the
weak thundershowers further west of our cwa. Wind gusts of
40-50mph have been observed with some of the weak rain showers
further west near the UT/WY/CO state borders. With the modeled
upper air soundings depicting an Inverted-V signature in the
lower boundary layer, and skinny CAPE further aloft, this
afternoon and evening is favored to see strong wind gusts with
the rain showers and thunderstorms. In fact, the HRRR is the
most aggressive with the deterministic output of wind gusts
between 45-75mph along the I-80 corridor of southeast WY between
21Z and 1Z this afternoon/eve. With the modeled soundings
depicting 30-40 knots from the surface to 500mb, the high-based
rain shower and thunderstorm activity may not have those highest
wind gusts realized in actuality. However, it is a possibility
as DCAPE readings over 1000 J/kg are also modeled, which is a
good rule of thumb for the higher potential of stronger wind
gusts. The rain showers and thunderstorm activity should wind
down by 6Z for most areas.

Thursday will be another mild to warm day. Scattered cloud cover
over the region will keeps temperatures slightly reduced near
seasonal averages. Model soundings show another afternoon and
early evening timeline of inverted-V signatures, so would expect
there to be elevated to potentially strong wind gusts when rain
showers and isolated thunderstorms occur. Similar timelines of
the mid-afternoon to early evening looks good for the slight
chance of showers and thunderstorms. PWATs will be slightly
lower, so the potential for brief downpours is limited. An upper
level ridge will amplify from the Four Corners region overnight
Thursday into Friday. This will bring the next round of warmer
temperatures to the area. A weak shortwave disturbance will be
embedded within the H5 upper level flow on Friday. A slight
chance of rain showers during the afternoon is progged, but the
concerns for fire weather will begin to creep upwards. Daytime
minimum humidity readings will range from 10-15% along and west
of the Laramie Range. Breezy winds will also be present during
the afternoon in this same area, so a possible fire headline may
be prudent in the coming forecast updates. Overall a warm
forecast remains on track, and the chances of rain showers
reduce slightly in the short term period.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 213 AM MDT Wed Aug 14 2024

Friday night/Saturday...West flow aloft will continue to dry out the
airmass and thus we will see correspondingly warmer temperatures
from the mid 80s to mid 90s. With precipitable water values lowering
to 0.4 to 1 inch and warm temperatures aloft increasing the
convective inhibition. it looks dry.

Sunday...Despite ridging aloft developing, we will see an increase
in atmospheric moisture content with precipitable water values
increasing to 0.6 to 1.4 inches. Thus, we expect an increase in
widely scattered to scattered late day showers and thunderstorms,
most numerous from the Snowy Range to far southeast Wyoming.

Monday/Tuesday...Atmospheric moisture content remains about the same
as on Sunday, and thus we expect another round of scattered late day
showers and thunderstorms each day, most numerous near the Colorado
state line from the Snowy Range to far southeast Wyoming. With
similar 700 mb temperatures, maximum temperatures should be about
the same as those from Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1044 PM MDT Wed Aug 14 2024

Shower activity across the area has diminished, leading to a quiet
overnight. Most terminals can expect light winds overnight with some
mid to high level clouds. VFR conditions expected during the day
Thursday, with diurnal wind gusts up to 25 kts. An isolated shower
or two will be possible Thursday evening.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...BW
LONG TERM...RUBIN
AVIATION...SF