Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

377
FXUS65 KCYS 261205
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
605 AM MDT Sat Sep 26 2026

.KEY MESSAGES...

- Warmer this weekend with temperatures around 5 to 10 degrees
  above normal. Slight Chance for Thunderstorms on Sunday as the
  next Pacific storm system moves onshore.

- A strong Pacific storm system will bring scattered showers and
  storms along with seasonably cool temperatures for the start
  to middle of next week, with a slow warming trend into the
  later part of the week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 155 AM MDT Sat Sep 26 2026

Pretty quiet weather expected this weekend with pleasant
conditions and temperatures around 10 degrees above seasonal
averages. There are some changes to Sunday afternoon as models
are trending towards a more unstable boundary layer with
increasing south to southeast winds...resulting in decent
moisture advection across the High Plains.

For today, models all in agreement showing mid to upper level
flow veering into the west. Surface winds are already starting
to respond early this morning with westerly winds observed along
and west of the I-25 corridor. This trend will continue through
the day with dewpoints lowering into the 30s to mid 40s. High
resolution models are showing some sprinkles or light rain
showers developing near the mountains. A quick look at the
soundings show a strong temperature inversion near 500mb with
poor lapse rates through most of the day. There is no forcing
present today with upper level ridging becoming dominant.
Expect mainly afternoon cumulus this afternoon with maybe a few
light sprinkles at times. Kept POP between 5 to 10 percent into
this evening. Otherwise, warm for late September with highs in
the mid 70s to mid 80s, warmest below elevations of 5000 feet.

Drying trend will be short-lived as all models showing return
flow off the Great Plains later in the day. Expect light and
variable winds in the morning to shift into the south to
southeast through the afternoon and evening hours. There is also
a Low Level Jet signature present across the eastern high plains
as 700mb winds climb above 35 knots Sunday evening. This will
result in moisture advection along and east of the I-25 corridor
through the day. There is even some midlevel moisture advection
over central Wyoming, ahead of the Pacific storm system moving
onshore. Continued to increase POP between 20 to 40 percent for
most of the forecast area starting Sunday mid afternoon and
continuing through the late evening hours as a midlevel
shortwave ejects northeast across the area colocated with an 80
knot jet max. Some thunderstorm activity is expected with CAPE
of 500 to 1000 j/kg east of the I-25 corridor.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Update issued at 110 AM MDT Sat Sep 26 2026

Will continue to monitor the Pacific storm system and remnants
of an eastern Pacific Hurricane on Monday and Tuesday. Current
00z models continue to trend towards split flow with the 00z GFS
particularly dry for our area and showing little to no
precipitation. The 00z Canadian does show the upper level low
tracking a bit more ENE with some decent rainfall possible along
the I-80 corridor and the mountains. Models are starting to
trend warmer for Tuesday and Wednesday, which is common with
split flow. 00z ECMWF is just arriving, and shows a solution in
between the Canadian and the GFS. Will continue to keep an eye
on this event, but as of right now, a much needed widespread
rainfall event looks unlikely at this time given the overall
pattern and the lack of a strong upper level ridge across
eastern half of the United States. Lowered POP, especially
north of the North Platte River Valley and tweaked temperatures
towards the 50th percentile of the NBM, GEFS, and ENS.

Previous discussion...
Issued at 220 PM MDT Fri Sep 25 2026

After a warm and largely dry weekend, the weather will turn more
unsettled once again as we head into the early part of next week. We
will have an interesting synoptic setup across the area, with the
typical upper level ridge over the southern Plains, combined with an
approaching Pacific trough. The wild-card factor here will be the
potential for an infusion of an exceptionally moist airmass ahead of
and associated with Hurricane Polo as it moves into Baja California
early next week. Unfortunately for our area which remains in drought
conditions, these factors do not look likely to align and produce
heavy rainfall for our area. Instead, the Pacific trough is trending
towards a split trough scenario. The northern branch will move
through on Monday, leaving behind a closed low in the southwest,
which eventually absorbs the remnants of Hurricane Polo. Moisture
will be abundant by Monday, with PW values around the 90th to 99th
percentile of climatology, but forcing and instability look
unimpressive at this time as the core of the northern branch of the
split trough passes to our north. Still, we should have enough to at
least support scattered showers and possibly a few thunderstorms.
Look for increased cloud cover and slightly cooler temperatures as a
result, though highs should still be a touch above seasonal
averages. A cool front with the northern branch system will knock
temperatures down by about 5-10 degrees for Tuesday. A chance for
showers remains in the forecast, but the most likely scenario at
this time leaves the closed low, and thus the potential for
widespread heavy rainfall, mainly to our south.

Heading into the middle of the week, the most likely scenario
supported by about 80+% of ensemble members features seasonable
temperatures and dry conditions as the upper level closed low spins
to our south. Cloud cover may spill into our southern zones
associated with the system to the south. While the probability of a
different scenario is low, it is still worth a mention. In about 20%
of ensemble members (and the AI-GFS), the closed low over the
southwest lifts more to the north instead of the east, which would
bring abundant wrap-around moisture into our High Plains zones
Wednesday into early Thursday. Regardless of the precipitation
potential, there is also a chance for some strong winds behind this
system. The official forecast reflects the former scenario, which is
far more likely at this time, but we can`t quite rule out the latter
just yet. After the closed low moves out, expect another warm-up
beginning Thursday, and peaking on Friday.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 605 AM MDT Sat Sep 26 2026

Fog and low CIGS still linger across small parts of the western
Nebraska Panhandle early this morning. Fog should lift shortly after
sunrise with mostly dry conditions and pleasant weather today. It
will be locally windy for the southeast Wyoming terminals and the
southern Nebraska Panhandle this morning and early in the afternoon.

HAZARDS/WEATHER TRENDS: Nuisance fog still lingers near KAIA early
this morning with VIS down to 1/4 mile at times. Expect this to
continue through 14z and possibly 15z before fog and low CIGS lift
after sunrise. Otherwise, VFR conditions will prevail for all
terminals over the next 24 hours. Westerly winds will gust around 30
knots for all of the southeast Wyoming terminals and KSNY until 21z,
with winds shifting into the south or southeast by this evening.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...MN/TJT
AVIATION...TJT