Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

585
FXUS65 KCYS 050013
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
613 PM MDT Mon May 4 2026

.KEY MESSAGES...

- An powerful cold front arriving Monday will bring a chance
  for showers and thunderstorms, changing over to snow Monday
  night and continuing into Wednesday morning.

- Accumulating snowfall is expected over 5500 feet in elevation,
  with significant snowfall likely (70% chance) in the Snowy
  Range, southern Laramie Range, and their adjacent foothills.

- 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,
  but confidence is lower for areas below 5500 feet in
  elevation.

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

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

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 402 PM MDT Mon May 4 2026

Tonight through Wednesday (The system): The RRFS has the front
moving through this evening around 6pm. This front will be the start
of the system as the moisture begins to lift and showers begin to
develop. The 12z Hi-Res models have a band of Frontogenesis (FGEN) or
enhanced precipitation right along the Colorado border and sort of
fill in amongst the mountain ranges. The snow levels will drop
quickly overnight going from about 9,000ft to 7-6,000ft by midnight
and then finally dropping below topography (4-5,000ft) by Tuesday
morning. This should quickly transition from rain to snow but in the
mountains and mountain adjacent areas. The band of enhanced snowfall
(FGEN) should temporary stall along the Colorado border increasing
snow rates and cooling down the ground to allow for measurable
accumulation instead of melting. Tuesday, a reinforcing upper level
shortwave will push through the Intermountain West. This wave will
push another stream of vorticity to help aid in the overall lift in
the northern half of our forecast area well as strengthen the
isentropic lift over the southern half and mountains. The Hi-res
models do develop another band of FGEN with this secondary trough.
This will essentially continue the snow showers in the mountains
with a rain/snow mix along and east of the I-25 corridor to the
Nebraska Border. The rain/snow mix may extend into Kimball,NE as the
heavier rates should keep it as such. But for most of the Nebraska
Panhandle, the precipitation will likely stay as rain from Tuesday
morning through the evening. Tuesday night into Wednesday morning, A
reinforcing shot of cold air overnight will transition the rain
showers into light snow. The snow showers are expected to start
tapering off through the afternoon. By Wednesday evening the showers
should have either dissipated or continued to follow the trough
moving southeast to not be our problem anymore.

SNOW ACCUMULATIONS: The Hi-res models have really ramped up snow
accumulations due to their placement of the band of FGEN. The 12z
model of the HRRR had snow accumulations between 14 to 18 inches of
snow for the CHeyenne area while the RRFS 12z run had between 8 to
10 inches. The ensemble means were used for the total snow
accumulations between the Euro/GFS/and Canadian Ensembles. The euro
ensemble mean was more heavily weighted as it seemed to do a better
job of the Snow shadowing that occurs over Laramie in easterly flow
due to the previous down sloping environment mentioned. So the snow
totals were updated to between 8-12 inches for Cheyenne, 4-6 inches
for Laramie and 2-4 inches for Rawlins. Do to the progged placement
of the strong FGEN the models converged on the Summit and Foothills
area and along I-80 between elk mountain and Cheyenne to receive
about 12-18 inches of snow. So that range has been roughly
consistent so totals were kind of left alone. The ensembles had
about 18-21 inches for the Snowy range and the Sierra Madre range 10-
13 inches. A Winter Weather Advisory was put out for the Sierra
Madre mountain range and the Winter Weather Watch was upgraded to a
Winter Storm Warning for the Central Laramie County area based upon
the new snow accumulations.

IMPACTS: Another challenge with this system is the degree of impact.
On one hand, the time of year and warm ground temperatures suggest
lesser accumulation on roadways. However, that doesn`t mean zero,
especially for any snow that falls at night. Roadways will probably
be slushy and slick late tonight through Tuesday, but then there
could be some re-freezing and icing concerns Tuesday night into
Wednesday morning as colder air moves into the area. In addition,
the snow is expected to be very heavy and wet. Thanks to the
exceptionally warm spring weather so far, deciduous trees are
leaving out across the area. Therefore, the snow weight is expected
to strain or break tree limbs, which could lead to some downed
powerlines and power outages across the area. These concerns will
need to be closely watched over the next 24 hours as the storm
system gets going.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 445 AM MDT Mon May 4 2026

The axis of the strong upper level shortwave trough is expected to
pass over the area Wednesday morning, which should abruptly conclude
the widespread lift, and also begin to advect in drier air aloft.
While some snow shower activity may linger into Wednesday afternoon,
we should be mostly done with the system by midday. The strong sun
will help to melt snow and improve travel conditions quickly,
especially as clouds clear in the afternoon hours. Wednesday will
still be quite chilly across the area, with highs expected in the
upper 40s to low 40s in areas receiving accumulating snow from this
system, and upper 40s to mid 50s elsewhere. Ridging will try to
build in across the western US by Thursday. Our area will remain on
the periphery of the ridge. Initially, expect a period of increased
winds as warm air advection takes over. Probabilities for high winds
remain around 20 to 40% in the wind prone areas on Thursday. Still,
a windy day can be expected for much of the area as temperatures
recover to near or slightly above seasonal averages.

The area is expected to remain under a fairly unsettled northwest
flow pattern through the end of the operational forecast period.
While temperatures will most likely recover to near normal, global
model guidance keeps a parade of upper level shortwaves moving
through the area every day or two. There are significant disparities
in timing and strength of each shortwave, which makes it difficult
to get into the details. The make take away is that the unsettled
weather pattern will keep chances for showers in the forecast for
much of the long term period. There is potential for another system
to tap into some cold air by the upcoming weekend, but only a
handful of ensemble members are cold enough for snow levels to drop
to the level of our populated areas.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 610 PM MDT Mon May 4 2026

A rather strong cold front for early May will sweep southward across
the terminals through this evening, ushering in a colder
airmass with widespread rain and snow south of a Rawlins to
Scottsbluff line, and less areal coverage further north.

Wyoming TAFS...High confidence in ceilings lowering from 8000
to 12000 feet, to 5000 feet this evening, then further lowering
to MVFR late this evening, then to IFR late tonight and
Tuesday morning and afternoon. Low confidence in isolated
thunderstorms until 01Z or 02Z producing wind gusts to 30 knots
and visibilities from 4 to 6 miles. High confidence in
widespread rain and snow showers developing this evening,
changing to all snow late tonight, with widespread IFR due to
visibility and clouds. After cold frontal passage, winds gusting
to 30 knots most of the period at Rawlins, and into early
evening at Laramie and Cheyenne due to thickness packing behind
the cold front.

Nebraska TAFS...High confidence in ceilings gradually lowering
this evening to low VFR, and remaining VFR at Chadron and
Alliance through the period, while Scottsbluff and Sidney have
ceilings and visibilities lowering to MVFR after 06Z in rain
and snow showers, then IFR at Sidney late tonight and Tuesday
morning before improving to MVFR in the afternoon. After cold
frontal passage, surface pressure packing and cold air advection
will help produce wind gusts to 30 knots for 3 to 6 hours after
the cold frontal passage.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 9 AM MDT Wednesday for WYZ103.
     Winter Weather Advisory from midnight tonight to 9 AM MDT
     Wednesday for WYZ105-106-115.
     Winter Storm Warning until noon MDT Wednesday for WYZ110-114-
     116-117.
     Winter Weather Advisory from 6 AM Tuesday to 6 AM MDT
     Wednesday for WYZ112.
     Winter Storm Warning from midnight tonight to 9 AM MDT
     Wednesday for WYZ118.
NE...None.

&&

$$

SHORT TERM...MN/MM
LONG TERM...MN
AVIATION...RUBIN