109
FXUS65 KCYS 150538
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1138 PM MDT Fri Mar 14 2025

.KEY MESSAGES...

-  Light snow in the mountains and snow showers in the Nebraska
   Panhandle will come to an end this afternoon and evening.

-  Widespread strong winds will continue through the evening
   hours along the I-80 corridor and most of the High Plains and
   NE Panhandle.

-  Another round of high winds and warming temperatures is
   increasingly likely for Sunday into Monday.

&&

.UPDATE...
Issued at 1136 PM MDT Fri Mar 14 2025

Cancelled the High Wind Warning for the North Snowy Range
Foothills, including Arlington and Elk Mountain, since the
winds have decreased below high wind criteria.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 111 PM MDT Fri Mar 14 2025

Current observations from across the area show snow along the
Interstate 80 corridor in Wyoming, and rain in parts of the Nebraska
panhandle. As the afternoon progresses rain will gradually
transition to snow as the cold front pushes further eastward.
Besides precipitation, observations also show strong wind gusts
across the eastern half of the CWA. High Wind Watches and
Warnings are in place through this evening. Models, including
the GFS and HRRR have trended winds downward this afternoon,
likely due to the progressive nature of this system with only a
briefly strong MSLP gradient. Widespread subsidence also does
not occur with the strongest winds aloft, limiting the potential
for high winds. For these reasons, did not have the confidence
to upgrade most of the remaining High Wind Watches. Winter
Weather Advisories also look on track to expire on time this
afternoon as Hi-Res guidance shows snow tapering off this
afternoon. Lingering snow showers will be possible this evening
across the CWA, however no additional accumulation is expected.
Strong winds will also taper off later this evening.

Heading into Saturday, the upper-level trough will still be solidly
locked over the center of the country, leading to seasonable cool,
but below average high temperatures. 700 mb temperatures will fall
to around -12C, but luckily the mid-March sun angle will keep
temperatures during the day from getting too cold. Highs will be in
the 30s and 40s across area with breezy conditions. Some lingering
snow showers can be expected during the day Saturday in the
mountains due to good mid-level moisture and orographic lift. A few
inches of new snowfall could be possible.

As the backside of the trough pushes into the CWA Saturday night,
winds will begin to increase as MSLP gradients tighten. 700 mb CAG-
CPR gradients will also increase above 50 meters late Saturday
night, causing winds aloft to increase. Winds aloft will
strengthen throughout the day, with 700 mb winds maxing out at
70 kts over the Laramie Range by late Sunday afternoon! Strong
subsidence is also present which will help get these winds down
to the surface. High winds will be likely for at least the wind
prones late Saturday night and through the day Sunday. At this
time, decided to hold off on any headlines since active High
Wind Watches and Warnings are already in effect. Besides wind,
much warmer temperatures are expected Sunday as upper-level
ridging moves into the Rockies, ushering in warmer air aloft.
With help from downsloping winds, areas east of the Laramie
Range could see highs in the 50s and 60s, while those to the
west see highs in the 40s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 111 PM MDT Fri Mar 14 2025

A high wind event will likely be ongoing on Sunday evening
lasting through most of the day on Monday throughout much of
southeast Wyoming and possibly extending as far east as the
Nebraska Panhandle. This event will be driven by a strong
gradient between a ridge of high pressure over the southwestern
CONUS and a trough sagging through the northwest. Aloft, a
potent jet riding up and over the ridge will enhance mid level
flow, all while over a favorable downsloping pattern over the
Laramie Range and front range corridor. Wind gusts upward of
50-60 knots are likely with these kinds of setups, as
highlighted by local in-house guidance recognizing patterns from
past events. Mild weather will also accompany this high wind
event, with lows well above average on Sunday night and around
15+ degrees above average for Monday afternoon. In fact, many
areas of the NE panhandle could take a run at the low 70s, with
low to mid 60s along the I-25 corridor in southeast Wyoming.

Attention then turns to our next weather-maker, a storm system
that will bring a sharp decrease in temperatures on Tuesday and
a chance for winter weather on Tuesday afternoon through
Wednesday. A shortwave trough will swing through the Pacific
Northwest coast on Monday and quickly move east through the
northern Rockies. Ensemble forecast guidance is in good
agreement showing a potent cold continental airmass
accelerating southward behind this system, resulting in a cold
front reaching the I-25 corridor near Douglass by sunrise on
Tuesday. This front will quickly dive south and eastward,
crossing through Cheyenne by noon and east of Sidney by early
afternoon. Behind this front, much colder air along with east to
northeasterly surface flow is progged by nearly all ensemble
guidance. With regard to precipitation, less confidence is
present in terms of the available moisture behind the anafront.
The ECMWF/ECMWF EPS has consistently been a bit more bullish
with moisture than the GEFS, and that trend continues today.
However, all ensemble guidance has continued to trend downward
with regard to precipitation, and most locations outside of the
mountains look to see less than 0.5" of QPF from this event.
Generally speaking, a 1-3, possibly higher, snowfall event is
still possible east of the Laramie Range. In the mountains,
6-12" looks to be a broad early call. Either way, a change to
below-normal temperatures looks like a high-confidence forecast
from Tuesday afternoon onward through the rest of the week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 507 PM MDT Fri Mar 14 2025

Very windy across all terminals this afternoon and evening.
Winds begin to decrease in the next 3 to 5 hours for Wyoming
terminals and the next 6 to 8 hours for the Nebraska terminals.
Mostly cloudy skies remain, but all sites are expected to
continue in VFR conditions. KRWL may see some residual snow
showers that could drop ceilings into the MVFR category, with
KAIA potentially seeing some rain showers dropping ceilings into
MVFR category. All sites return to VFR conditions for the
overnight hours, but cloudy skies remain.

&&

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

&&

$$

UPDATE...RUBIN
SHORT TERM...SF
LONG TERM...MAC
AVIATION...AM