953
FXUS65 KCYS 032335
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
535 PM MDT Thu Apr 3 2025

.KEY MESSAGES...

- Below average temperatures will continue late this week and
  into the weekend.

- Periods of accumulating snow expected today through early
  Saturday morning. Travel impacts are possible, especially over
  the higher elevations.

- Warmer and drier conditions begin on Sunday and likely linger
  through much of next week.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 220 PM MDT Thu Apr 3 2025

Latest radar loop/observations were showing light snow showers starting
to cross the I-80 corridor. This activity is associated with
broad scale isentropic lift between 295-300k induced by the left
exit region of the upper level jet tracking through northwest
Kansas and southern Nebraska. This area of lift should continue
tracking to northeast towards Alliance and Scottsbluff by 00z,
and then head towards north central Nebraska by midnight. As a
result, the bulk of the snowfall will generally fall along and
south of the Pine Ridge this evening and overnight. Snowfall
accumulations should generally be an inch or less across this
region tonight, due to warm ground temperatures and higher
dewpoints. The HREF is showing rates this evening around 1/2
inch an hour for a couple of hours this evening around Kimball,
Banner and eastern Laramie counties, but these rates diminish
considerably overnight. Later shifts will need to keep an eye on
this area for a possible snow advisory especially if the rates
end up being a little higher than expected. Otherwise, snowfall
will continue over the mountains this afternoon into the
evening. The highest amounts should occur in the Sierra Madre`s
where 2 to 3 inches are common thus far with more snowfall
possible there and the Snowies this evening.

Light to moderate snowfall will be the theme across the area through
Friday as a mid level trof (700-600mb) swings through the area.
This will cause our low level flow to turn to the north and
will result in higher snowfall amounts along the north facing
ridges of the Pine Ridge, northern Laramie Range and Cheyenne
ridge. This trof is expected to swing through areas west of the
Laramie Range in the morning and the remainder of the area
during the afternoon. Some banded snowfall will be possible as
it pushes southeast. Once the trop passes through we should
start to see snow showers taper off during the afternoon.
However, I would not surprised to see the snow showers linger
underneath the broad scale upper level diffluence during the
afternoon.

High pressure is expected to settle across the region Friday
night with clearing skies expected. This will allow for ideal
radiational cooling. As a result, we dropped temperatures closer
to the 25th percentile of the NBM with overnight lows ranging
from 10 to 15 degrees. A gradual warmup is expected on Saturday
as the upper level ridge tries to nose its way into the area,
but we will still be under the influence of northerly flow which
will keep us on the chilly side. Meanwhile, downslope flow will
start commencing on Saturday night which will allow for
temperatures to rebound slightly from the previous night.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 220 PM MDT Thu Apr 3 2025

Main concerns in the long term will be a warming trend along
with mostly clear skies under high pressure ridging, leading to
mostly benign conditions through this portion of the forecast
period. Sunday begins as ridging starts overtaking our area,
leading to clearing skies and increasing warmth, including highs
into the the 50`s to some low 60`s possible. And the warmth only
continues to increase as we move into the beginning of next
week, with widespread 60`s on Monday followed by some locations
peaking into the low 70`s by Tuesday. This warming trend will
be briefly stunted by a passing shortwave system on Tuesday into
the early part of Wednesday, helping to flatten out this ridge.
Prior to the passage of this system on Monday, we should see
breeziness return to the region thanks to the tightening of the
pressure gradients alongside the jet that will accompany this
system. In house guidance is noting this uptick in winds, but is
still skeptical that we will reach high wind criteria, as the
highest probabilities for 58+ mph winds are limited to just
around 40% for the Arlington area on Monday afternoon. But the
25th-75th percentiles are averaging around 40-50 mph for our
usual wind prone locations from Monday through Wednesday, so
expect at least breezy conditions with this system.

Alongside the winds, there may be a risk of some precipitation
as well on Tuesday into Wednesday, but these probabilities are
even lower than the wind risk. With westerly flow alongside
fairly dry surface conditions and limited forcing, most activity
that can form should be relegated to the mountains, and even
here the NBM shows only a 15-20% probability at greater than 0.2
inch of QPF, hardly a soaker. Mostly, we should see a few
passing clouds and some virga at best. As the long term ends
Wednesday night into Thursday morning, ridging will begin to
restrengthen over the region, and is likely to lead to even
warmer temperatures just beyond the forecast period. With
ensemble clusters nearly unanimous on this forecast pattern with
just some minor differences in the strength and placement of
these features, there is high confidence (70-80%) in the
forecast.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 522 PM MDT Thu Apr 3 2025

A passing weather disturbance and cold front will bring chances
for snow to the region tonight and Friday.

Wyoming TAFS...Ceilings will range from 2000 to 4000 feet until
18Z, with occasional light snow and fog reducing visibilities to
3/4 to 5 miles and ceilings to 500 to 2500 feet, then ceilings
will range from 3500 to 5000 feet after 18Z. Winds will gust to
30 knots at Laramie until 02Z, and to 25 knots at Cheyenne after
12Z Friday.

Nebraska TAFS...Ceilings will range from 300 to 2500 feet until
15Z, with occasional light snow and fog reducing visibilities to
1/2 to 5 miles, then ceilings will improve to 3500 to 5000 feet
after 15Z Friday. Winds will gust to 27 knots at Chadron,
Alliance and Scottsbluff until 03Z, then will gust to 35 knots
at Alliance, Scottsbluff and Sidney after 15Z Friday.

&&

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

&&

$$

SHORT TERM...REC
LONG TERM...CG
AVIATION...RUBIN