371
FXUS65 KCYS 092333
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
433 PM MST Sat Nov 9 2024

.KEY MESSAGES...

- Light snow will taper off in southeast Wyoming and the far
  southwest NE panhandle through this afternoon. Precipitation
  expected to taper off from west to east through the day today.

- Warmer temperatures expected for Sunday and Monday ahead of
  the next potential high wind event on Tuesday/Wednesday.

- An occasionally windy and mostly dry period will occur for
  Tuesday through Saturday, with near normal temperatures for
  Tuesday, Wednesday and Saturday, and above normal temperatures
  for Thursday and Friday.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 217 PM MST Sat Nov 9 2024

Cold temperatures and light rain or snow showers continue to
slowly move through the area as of 20Z this afternoon. Much
needed precipitation was a welcomed sight earlier today for
several locations. Many areas have received over 0.5 inches of
either rainfall or liquid melted equivalent from snowfall as of
Saturday morning. Daytime highs have topped off in the upper 30s
to lower 40s for the lower elevations. Visibility reductions are
still present in some areas of southeast Wyoming as the upper
level system slowly propagates to the east-northeast this
afternoon. We can expect the snow and rain showers to slowly
dissipate in coverage as the upper level system ultimately
pushes further east in the next 12-24 hours.

On the heels of the departing upper level wave, we will see
mid-level atmospheric heights rise overnight courtesy of an
amplifying ridge further upstream. The associated dome of
surface high pressure will propagate into the area on Sunday,
and we can expect mostly sunny skies. This will assist with
making it much warmer outside for daytime highs. Locations along
and east of the I-25 corridor on Sunday will easily reach or
exceed 55 degrees. 700mb winds will also increase in speeds,
with 30-40 knots modeled along the spine of the Laramie Range
and gap areas of southeast WY. This will translate to breezy
winds for many areas, making the temperatures not feel as mild.
A weak disturbance aloft is expected to propagate off the main
500mb steering flow Sunday night into Monday from an advancing
mid-latitude cyclone across the Pacific Northwest. Surface
pressure tendencies will tighten slightly as a surface low will
develop and deepens slightly across eastern WY and western SD.
Weak surface winds overnight on Sunday into early Monday morning
combined with the nighttime subsidence inversion could result
in localized patchy fog by daybreak across the valley areas of
the NE Panhandle.

Modest upper level ridging is expected on the backside of the
ridge axis on Monday. As this amplifying upper level ridge
propagates toward the Central and Northern Plains, the
aforementioned upper level weather system from the Pacific
Northwest will head toward the Four Corners region of the desert
Southwest. 700mb temperatures of +3C to +5C should make for
another mild day for Monday. Expect daytime highs in the 50s are
areas east of the Laramie Range, and slightly cooler
temperatures in the 40s for locations west of the Laramie Range.
Mild overnight lows will be present Monday night ahead of the
next weather system to impact the area. Should be a breezy night
for the higher terrain, which will keep temperatures elevated
due to consistent mixing in the lower boundary layer. Overnight
lows in the 20s to near freezing are expected. By daybreak, the
breezy winds will begin to spread further east.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 217 PM MST Sat Nov 9 2024

Tuesday...As a trough aloft moves overhead, the low and mid level
gradients strengthen significantly, possibly portending another high
wind event for our Wyoming wind prone locations, as also seen on our
high wind models. Temperatures will be slightly cooler for most
locations. Looks like enough low and mid level moisture, and lift,
to produce scattered snow showers mainly west of a Douglas to
Laramie line.

Wednesday...Cooler temperatures develop in the wake of a cold
frontal passage and with zonal flow aloft developing. With 700 mb
temperatures near -1 Celsius, maximum temperatures will only be in
the lower 40s west of I-25, and upper 40s to mid 50s east of I-25.
Continued breezy to windy based on the projected low and mid level
gradients.

Thursday...The flow aloft backs from westerly to southwesterly
inducing another surface lee trough development, and with 700 mb
temperatures rising to near 4 Celsius, highs will warm to the upper
40s to mid 50s west of I-25, with upper 50s to mid 60s east of I-25.
Continued breezy to windy based on the low and mid level gradients.

Friday...As another shortwave trough aloft moves into our region,
our flow aloft remains southwest with 500 mb heights falling about
140 meters, thus slightly cooler temperatures expected with low and
mid level gradients suggesting another windy day, especially for our
Wyoming wind prone locations such as Arlington, Bordeaux, Vedauwoo
and the I-80 Summit.

Saturday...Cooler and breezy in the wake of a shortwave trough aloft
and its associated cold frontal passage. 700 mb temperatures near -6
Celsius will yield maximum temperatures in the lower to mid 40s west
of I-25, with mid 40s to mid 50s east of I-25.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 422 PM MST Sat Nov 9 2024

A potent upper low will move from central Nebraska this evening,
to northwest Iowa by Sunday morning, then westerly flow aloft
will develop across the terminals.

Wyoming TAFS...Clear skies will prevail at Rawlins, with wind
gusts to 23 knots until 02Z, and to 30 knots after 16Z Sunday.

For Laramie and Cheyenne, ceilings will range from 3500 to
5000 feet until 04Z, with occasional light snow reducing
visibilities to 4 miles and ceilings to 2500 feet until 02Z.
Scattered clouds from 8000 to 12000 feet will occur after 04Z.
Low level wind shear occurs at Laramie after 04Z, and at
Cheyenne from 02Z to 17Z.

Nebraska TAFS...At Chadron and Alliance, ceilings will range
from 2500 to 3500 feet until 03Z, with occasional light rain and
fog reducing visibilities to 3 miles and ceilings near 1500 feet
until 03Z, then ceilings will be near 4500 feet from 03Z to
08Z, then skies will be clear.

For Scottsbluff and Sidney, expect ceilings near 3500 feet until
07Z, with occasional light rain and fog reducing visibilities to
4 miles with ceilings from 1500 to 2500 feet, then mostly clear
skies will occur after 07Z. Winds will gust to 25 knots at
Sidney until 03Z.

&&

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

&&

$$

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