Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

275
FXUS65 KCYS 281109
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
509 AM MDT Wed Oct 28 2026

.KEY MESSAGES...

- Dry, warm, and breezy conditions are expected to continue
  through Thursday, with mild overnight lows.

- Chances for a few showers return Friday into Saturday
  (Halloween) with temperatures remaining mild.

- A pattern change to colder, wetter, and windier conditions is
  favored Sunday into Tuesday, but the details remain highly
  uncertain at this time.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 150 AM MDT Wed Oct 28 2026

Another relatively quiet night is in store for SE Wyoming and the
Nebraska Panhandle, with no widespread precipitation expected aside
from a few light showers that may manage to sneak into northern and
western portions of Carbon County. These are associated with a weak
mid-level disturbance that is currently moving across Western
Wyoming and Utah which can be seen clearly on GOES mid-level water
vapor imagery. Although most areas will remain dry, did decide to
increase PoPs mainly for Rawlins and points north and west if a
shower does decide to sneak into the area.

Current METARs and web cameras are showing some dense fog across Box
Butte, Morrill, and Cheyenne Counties in the Nebraska Panhandle, so
went ahead and included these areas in a Dense Fog Advisory until
8AM MDT. Will have to monitor trends via satellite imagery across
the western counties of the Nebraska Panhandle for fog, however
expecting the most widespread, dense fog to remain east of a
Scottsbluff to Kimball line. The moist conditions this morning are
being driven by a weak lee trough which is inducing SE cyclonic
upslope flow, and is expected to cease into the day as the flow
becomes more out of the west or southwest. As we know, westerly
winds translates to downslope flow in our area, and therefore
adiabatic warming as the air descends the higher terrain onto
lower elevations, so we can expect a similarly mild day to
Tuesday. High temperatures are expected to again stand 5-10
degrees above average for this time of year, with low to mid 60s
forecast east of the I-25 corridor, and low to mid 50s east of
the Laramie Range. As for our winds, not expecting as strong of
winds as we did yesterday over the wind-prone areas along I-80,
however cannot rule out some gusts of 50-55 mph around sunrise.
700 mb flow will begin to relax by noon as weak shortwave
ridging builds across the Northern Rockies. Expect another quiet
night overnight into Thursday underneath the weak ridge, with
mostly clear skies and generally light winds.

Lows on Thursday morning are still expected to be fairly mild for
this time of year, with locations in the Nebraska Panhandle staying
mainly in the upper 30s to low 40s, with SE Wyoming staying above
freezing in the low to mid 30s, although Laramie may briefly dip
below freezing. For perspective, the average low in Cheyenne on
Thursday is 30 degrees, with a low of 37 degrees currently in the
forecast. During the day on Thursday, the mid-level ridge will begin
to amplify over the Upper-Midwest, placing us in a SW flog regime.
This will continue the trend of dry and warmer than average
conditions as NAEFS guidance has 500 mb geopotential height values
ranging from the 75-80th percentile underneath the building ridge.
This will translate to high temperatures mainly in the low to mid-
60s east of the Laramie Range, and slightly cooler mid to upper 50s
in places like Laramie and Rawlins. Another mild night is expected
Thursday into Friday, with many locations in the Nebraska Panhandle
struggling to dip below 40 degrees by Friday morning, and the
population centers (at least for Wyoming standards) across SE
Wyoming staying above freezing in the mid to upper 30s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 150 AM MDT Wed Oct 28 2026

A broad, upper-level ridge will sit across the central CONUS Friday
morning leading to modest southwesterly flow across the region.
Unlike previous patterns, this ridge will not be as strong and
temperatures will not warm nearly as much. The next upper-level
system will be slowly moving into the Pacific Northwest throughout
much of the day Friday, though its progression will be slow. The
base of the trough will remain offshore through at least early
Saturday morning. A very weak shortwave will attempt to push through
the region on Friday, leading to very weak, synoptic ascent mainly
across western Nebraska and mainly later in the day as the shortwave
approaches the region. 700mb slow remains from the southwest and
fairly weak, with the shortwave barely visible as it progresses
northeastward and is, ultimately, absorbed into the larger scale
flow. 700mb temperatures remain in the 4 to 6C range across the
region throughout the day Friday, so expect temperatures in the
upper-50s to low-60s everywhere. Surface is currently forecast to be
out of the south-southeast for all locations east of the Laramie
Range and out of the southwest for all locations west of the Laramie
Range. By 18Z Friday the NAEFS Mean Precipitable Water will increase
to above the 90th percentile for portions of western Nebraska and
barely into southeast Wyoming before increasing to above the 90th
percentile nearly everywhere east of the Laramie Range by 00Z
Saturday. Therefore, moisture will not be a limiting factor as the
weak forcing moves through, as has been the case for the last
several systems. The biggest concern will be whether or not the
ascent from the weak shortwave and systems moving out of the
southwestern CONUS will be enough to get showers going across
western Nebraska. If it is, these showers are expected to remain
rain with snow not anticipated at this time.

Precipitable water values will remain well over the 90th percentile
for most places throughout the weekend, which may put a small damper
on Halloween festivities on Saturday evening and night. This
disturbances off to the southwest will push towards the region on
Saturday, increasing forcing across the region. The upper-level
trough over the Pacific Northwest will maintain its slow movement
inland Saturday, with the trough axis sitting over Idaho and the
Nevada/Utah border by early Sunday morning. A few lobes of 500mb
vorticity will eject across the CWA throughout the day Saturday, but
these look to be weaker than what is expected for Sunday. 700mb flow
begins to amplify later Saturday into the early morning hours Sunday
as the 700mb system starts to take shape across western Montana. As
of now, a strong 700mb jet looks to develop just to the northeast of
the CWA throughout the evening on Saturday, which would likely
increase precipitation chances west of the Laramie Range as this
region remains in the right entrance region of the low-level jet.
Winds will also likely start picking up Saturday night into early
Sunday morning for this same region. Luckily, or not if you like
snow, 700mb temperatures are expected to remain well above the -2 to
0C range, likely in the 2 to 5C range, which favors any
precipitation falling as rain and not snow. So what does this mean
for trick-or-treating and other Halloween activities? Well, as of
now, precipitation looks to hold off for the most part until early
Sunday morning, unless you are trick-or-treating in the Snowy Range.
Temperatures will quickly drop into the 40s for most places by 8PM
Saturday night, so it looks like there will be a lot of superheroes,
witches, and vampires with jackets. Luckily, precipitation should
hold off until festivities end.

Much of the remainder of the long term forecast remains very
uncertain as model confidence and agreement worsens Sunday through
Tuesday. The early forecasting shift talked about the possibilities
in depth, so please read the following for a discussion on the
Sunday through Tuesday time period...

Forecast confidence decreases considerably as we head into the
Sunday through Tuesday time period. While there is still potential
for widespread precipitation, the ensemble spread is enormous as a
very complex weather pattern sets up over the Western CONUS. First,
a powerful disturbance will race into the southwest, riding on a
very strong sub-tropical jet stream. Meanwhile, a northern branch
trough will dive into the northwest and progress eastward
simultaneously. The northern upper level low may also close off from
the polar jet itself, adding to the uncertainty. With so many moving
parts on the board, it is difficult to have much forecast confidence
in how this will play out.

In lieu of that, we can discuss some possible scenarios.
Approximately 45% of LREF members are clustered into a scenario
showing a more progressive storm system. This is further split
between about half of this camp showing a storm that remains
progressive, and half showing a storm that eventually closes off and
strengthens, but this occurs too far east to deliver much
precipitation to our area. In this scenario, most of the area could
expect light precipitation amounts, generally 0.25" or less. The
remaining 55% of ensemble members have a deeper, stronger system
with better forcing for lift, and thus improving chances for
precipitation. About 30% of the full ensemble suite (a subset of the
55%) have a moderate precipitation event, where the system is strong
and deep, but still progressive. The final 25% (again a subset of
the 55%) depict a slow, strong upper level low closing off before
reaching our area, which would lead to widespread heavy
precipitation for much of the area, but especially over the High
Plains. The ECMWF Extreme Forecast Index provides some additional
context. EFI values for QPF on Monday are only around 0.5 to 0.7,
suggesting low confidence in a significant event. However, the shift
of tails values exceed 2.0 over much of the High Plains, which tells
us that a small subset of ensemble members depict an extreme event.
Thus, the main takeaway at this time should be that at least some
light precipitation is narrowly favored (60% chance) over much of
the area Sunday PM into Tuesday AM, and there is potential for
significant rain and/or snow, but the probability of this scenario
is fairly low (25% chance) at this time. Nonetheless, this is high
enough to discuss and continue to monitor closely in the coming
days. Most model guidance shows limited cold air with this system
once again, and the wettest ensemble members also tend to be the
warmest (as these close the low off faster). This will make snow
levels an issue once again. Regardless of the precipitation outcome,
expect cooler temperatures by Monday with blustery conditions. There
is potential for high winds as well, but we`ll wait to get a better
idea of the storm`s evolution before diving into those details.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 509 AM MDT Wed Oct 28 2026

Low clouds and fog are ongoing at KBFF, KAIA, and KSNY this morning
with all sites at either LIFR or VLIFR. These conditions are
anticipated to continue through 15Z, with clouds starting to slowly
clear as early as 14Z. All terminals are expected to return to VFR
conditions after 15Z and throughout the remainder of the 12Z TAF
period. Gusty winds are expected today, with a northerly wind shift
anticipated at KCYS, KBFF, KCDR, KSNY, and KAIA later this afternoon
into the evening hours. Low-level wind shear is possible at KCYS and
KLAR through 16Z this morning.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...Dense Fog Advisory until 8 AM MDT this morning for NEZ003-019-
     021-055.

&&

$$

SHORT TERM...NB
LONG TERM...MN/AM
AVIATION...AM