Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

813
FXUS65 KCYS 051136
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
536 AM MDT Tue May 5 2026

.KEY MESSAGES...

- A significant, late season snow storm is moving across the
  area. The greatest impacts are  between Tuesday afternoon and
  Wednesday morning.

- Snow will accumulate over 5500 feet in elevation, with
  significant snowfall expected in and near the Snowy Range and
  southern Laramie Range

- Snowfall is expected to be heavy and wet, which could damage
  tree limbs and produce power outages.

- Travel impacts due to snowfall are expected along Interstate
  80 between Rawlins and Cheyenne, and Interstate 25 between
  Wheatland and the Colorado state line.

- Impacts may extend eastward on Interstate 80 towards Kimball,
  mainly Tuesday afternoon and Tuesday night as colder air moves
  into the area.

- Drier, warmer, and windier weather returns to the area for the
  second half of the work week.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 400 AM MDT Tue May 5 2026

The significant, late season snow event is underway across the area
this morning. Overall, the forecast remains largely on track with
relatively minor adjustments made to the official forecast with the
latest update. Current GOES water vapor imagery shows the synoptic
features in place to set up active weather over the next few days.
The broad, closed upper level low over the West Coast is meandering
inland this morning, with abundant Pacific moisture stretched out
from northern California towards our area. Meanwhile, the northern
branch shortwave is apparent over central Montana this morning,
which will be bringing a reinforcing shot of cold air and forcing
for lift sometime this afternoon. The latest mesoanalysis shows
potent frontogenesis parked more or less right along the I-80
corridor this morning. Overrunning isentropic lift is primarily over
northern Colorado but extends just across the state line and into
the I-80 corridor. These two forcing modes are driving widespread
precipitation, mainly over the southern half of the forecast area.
Laramie is the winner so far, picking up 0.23" liquid as rain last
evening, and another 0.27" as snow as of 3AM. The current phase of
the system is expected to last through around sunrise or perhaps a
few hours later. After that, models show the strongest frontogenesis
slipping to our south. Isentropic lift will keep scattered
precipitation going through the morning hours, but we should see
rates ease while coverage on radar becomes a little spottier.
Plentiful cloud cover will keep unseasonably cold temperatures over
the area today. Laramie, Cheyenne, and possibly Rawlins will
probably hover within a few degrees of freezing all day, while
others will only make it to the 40s at best. Chadron will be the
warmest spot, as the area is unfortunately expected to miss out on
this event.

The second phase of the event will kick up this afternoon as the
reinforcing shortwave trough mentioned above pushes southward. Look
for increasing isentropic lift, followed by another surge in
frontogenesis later as the upper level low strengthens and begins to
absorb the Pacific closed low. This feature will also bring an
additional surge of cold air through the area, which should cause
snow levels to drop again this afternoon and evening. More cold air
and stronger forcing will thus increase the coverage of snow impacts
across the area. Due to this, the Winter Weather Advisory was
expected to include central and northern Carbon County beginning at
6PM, and eastern Laramie and Kimball counties beginning at 3PM.
Laramie remains an area of greater uncertainty. So far, the low-
level easterly downslope flow appears to have been easily cancelled
by the synoptic forcing. Current thinking is that the downslope flow
will dominate later in the event when we lose the powerful
frontogenesis. However, current forecast snow totals are pretty
close to Warning criteria for the city, so we will need to watch
this closely for an upgrade to a Winter Storm Warning if needed.

Concerning total liquid and snow amounts, the forecast has
changed little since yesterday. The official forecast
incorporates a blend of HREF and ECMWF ensemble guidance for
QPF, and ends up a little below the NBM which still looks a
little on the aggressive side. The most likely amounts are
currently around 8" in Cheyenne, 5" in Laramie, 3" in Kimball,
and 3" in Rawlins. The higher elevations of I-80 around
Arlington and the Vedauwoo area still look like the bullseye of
this system, with 10 to 18" expected. It would not be a surprise
to see some amounts locally over 2 feet show up in the Snowy
Range, the southern Laramie Range, or their adjacent foothills.
We have seen the 10th and 90th percentiles closing the gap a
little bit over the last 24 hours as confidence improves, but
there is still a fairly wide range of outcomes, which will
largely depend on how long we can keep strong frontogenesis in
place in our area. In terms of impacts, travel conditions could
improve a little during the day today with the benefit of the
strong early May sun, but expect this to deteriorate in the late
afternoon or evening again as temperatures cool again. The
heavy wet snow accumulation on trees remains a primary concern
with this event. As trees are largely leafed out or in the
process of leafing out, trees will accumulate more snow than
usual, which is already expected to be of a fairly dense
quality. Therefore, damaged or downed trees and possibly
powerlines will be a concern through Wednesday morning.

Model guidance differs in how long precipitation will last into
Wednesday. The upper level low will dive nearly straight north to
south, and recent guidance shows this system trying to close off as
it absorbs the Pacific low pressure system. This could allow
overrunning isentropic lift to continue through much of the day,
although even in this case, rates should be fairly light by this
time. With lower rates and the help of the high sun angle,
conditions should improve Wednesday morning. All headlines continue
through 9AM Wednesday, except the higher terrain which expire at
12PM Wednesday. Once the axis of the upper level shortwave trough
finally passes through the area, much drier air and subsidence
will move in overhead, but it is still unclear if that will be
Wednesday morning, or as late as early Wednesday evening.
Wednesday will be another chilly day regardless, but high should
climb a few degrees above today`s values. In addition to the
snow, we will have a widespread freeze tonight, and this will
locally be a hard freeze.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 400 AM MDT Tue May 5 2026

Drier air will move in overhead Wednesday night, leading to clearing
skies. Areas with fresh snow cover (primarily Laramie and Cheyenne)
may have a window to see temperatures drop quickly before westerly
winds and strong warm air advection returns late Wednesday night or
Thursday morning. We could see overnight lows reached in the
evening, with warming occurring later as the winds pick up. The
arctic high pressure moving through over the next few days will be
settled in over the interior Rockies by Wednesday night. On the
large scale, the overall weather pattern will shift into a northwest
flow pattern with a ridge located over the West Coast, and the
persistent upper level trough remaining over the Hudson Bay region.
Another progressive shortwave will approach the area as early as
Thursday. This feature will be accompanied by a surface trough,
which will drop surface pressure over the High Plains. As a result,
we will need to watch for the potential for a gap wind event
Wednesday night into Thursday morning. High wind probabilities
remain around 30 to 40%. Interestingly, this event appears to a low-
level / surface driven gap wind event, which is somewhat unusual
this late in the wind season. 700-mb winds look unlikely to exceed
50 knots, and 700-mb height gradients are fairly unimpressive. For
now, winds were nudged towards the NBM 90th percentile in the
official forecast, but remain below high wind criteria. Both the
Arlington/Elk Mountain and I-80 summit areas will have ample snow on
the ground when the winds pick up. We could have some blowing snow
concerns, but there is a lot of uncertainty in this owing to the
snow consistency and how much thawing (i.e. wetting the snow) can
occur on Wednesday.

Expect a breezy to windy day elsewhere Thursday with temperatures
quickly recovering to near seasonal averages. The Laramie to
Cheyenne corridor will remain cool, but the rest of the area should
warm above average. The next shortwave aloft will arrive late
Thursday, and will bring a chance scattered showers and isolated
thunderstorms across the area Thursday afternoon and Thursday night.
This will not bring much rainfall, but temperatures will be warm
enough that we will not have to worry about snow. The northwest flow
pattern should remain fairly locked in place through the weekend.
Overall, expect temperatures near seasonal averages and breezy to
windy northwest winds every day. We will also remain fairly
unsettled, with chances for showers each day.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 529 AM MDT Tue May 5 2026

Rain and snow continues to move across the area this morning.

WYOMING TAFs: Moderate to heavy snowfall continues to move
through CYS and LAR. This will continue today, but occasional
lulls and breaks are expected, particularly between sunrise and
about midday. While we may recover to MVFR or even briefly VFR,
these will not last too long. RWL will see the opposite, with an
initial round of snow moving in this morning. A second round of
snow will pick up this afternoon around LAR and CYS,
intermittently filling into RWL as well. IFR to LIFR will
prevail through the night tonight with snow and low CIGs
continuing. RWL can expect to see some gusty northeast winds
through the period.

NEBRASKA TAFs: Showers are moving through the southern
panhandle this morning. This morning, expect to oscillate
between MVFR and VFR due to low CIGs as showers move through.
The exception is SNY, where current temperatures are very close
to allowing snow to mix in. If that occurs, IFR conditions will
occur. A brief stronger shower near BFF and AIA may allow snow
to reach the ground and produce IFR conditions. Overall
confidence in the timing of CIG/VIS drops in Nebraska is quite
low.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory from 3 PM this afternoon to 9 AM MDT
     Wednesday for WYZ119.
     Winter Weather Advisory until 9 AM MDT Wednesday for WYZ103-
     105-106-115.
     Winter Weather Advisory from 6 PM this evening to 9 AM MDT
     Wednesday for WYZ104-109.
     Winter Storm Warning until noon MDT Wednesday for WYZ110-114-
     116-117.
     Winter Weather Advisory until 9 AM MDT Wednesday for WYZ112.
     Winter Storm Warning until 9 AM MDT Wednesday for WYZ118.
NE...Winter Weather Advisory from 3 PM this afternoon to 9 AM MDT
     Wednesday for NEZ054.

&&

$$

SHORT TERM...MN
LONG TERM...MN
AVIATION...MN