341
FXUS65 KCYS 151741
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1141 AM MDT Thu Aug 15 2024

.KEY MESSAGES...

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

- Seasonable temperatures will continue through the period.
  Showers and thunderstorms will be most likely on Sunday and
  Monday, with less coverage for Tuesday and Wednesday.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 211 AM MDT Thu Aug 15 2024

Cold front that was over the CWA yesterday has pushed well south
into southern Colorado this morning. A 1025mb surface high over
northwestern Wyoming giving us breezy west to northwest winds
and morning temperatures in the low 50s across southeast Wyoming
and even some 40s out near Saratoga. Warmest temperatures in the
Panhandle and the Platte River Valley...where 60s are still
being reported.

A much drier day expected today as PWATS continue to fall. Still
a chance for showers and storms however. RAP and HRRR simulated
radar showing showers developing across the Laramie Range and
points west for this afternoon that continue into the evening
hours. Greatest coverage will be near the Colorado stateline and
along the I-80 corridor. Areas north of Interstate 80 look to
remain dry east of the Laramie Range.

Becoming concerned for Friday as the upper ridge builds into the
CWA. 700mb temperatures quite warm Friday with +16 to +18C over
Carbon and Albany Counties. With temperatures in the mid
80s...afternoon humidity expected to fall quite low. GFS
700/750mb winds up near 25-30kts that will mix down with these
warmer temperatures. Decided to issue a Fire Weather Watch for
Friday. Day shift can decide on whether to upgrade after
possibly some coordination with responsible fuels personnel.

Saturday will be another dry and breezy day for much of the
CWA. May need fire weather headlines for Saturday as well. GFS
700mb winds even stronger and more widespread Saturday.
afternoon.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Issued at 211 AM MDT Thu Aug 15 2024

Saturday night/Sunday...Despite ridging aloft developing, we will
see an increase in atmospheric moisture content with precipitable
water values increasing to 0.6 to 1.8 inches. Thus, we expect an
increase in 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
for Monday, with a decrease on Tuesday. Despite ridging aloft, we
still anticipate scattered to numerous showers and scattered
thunderstorms on Monday, most numerous near the Colorado state line,
with a decrease in coverage for Tuesday. Maximum temperatures will
remain about the same each day.

Wednesday...Although ridging aloft continues, precipitable water
values remain nearly the same as Tuesday, ranging from 0.5 to 1.2
inches. Thus, it looks like widely scattered to scattered late day
showers and thunderstorms again, most numerous near the Colorado
state line. 700 mb temperatures remain near 19 Celsius, yielding
maximum temperatures from the mid 80s to mid 90s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1134 AM MDT Thu Aug 15 2024

A very quiet period is expected during the next 24hrs, due to
a high pressure ridge settling over the area. This high
pressure system will be shortlived as another disturbance rides
over the ridge this evening and overnight. This disturbance may
kick off a few showers across the KRWL...KLAR and KCYS TAF sites
mainly after 00z. Otherwise, a weak boundary will pass through
the forecast area this evening causing the wind to shift to the
north briefly before becoming more variable overnight.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Fire Weather Watch from Friday afternoon through Friday
     evening for WYZ420>423-425-427-428.
NE...None.

&&

$$

SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...RUBIN