Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

589
FXUS65 KCYS 220458
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1058 PM MDT Mon Sep 21 2026

.KEY MESSAGES...

- Cool and seasonable temperatures will continue through mid-
  week, with a warming trend expected for the second half of the
  week into the weekend.

- Limited precipitation chances Tuesday evening into Wednesday,
  with a brief dry pattern starting Friday and lasting through
  the weekend.

- Breezy conditions will be possible across much of the region
  Tuesday and Wednesday, especially across the western Nebraska
  Panhandle.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 338 PM MDT Mon Sep 21 2026

The upper level low responsible for yesterday`s storms is currently
pushing eastward as its currently sitting over the Northern Plains
with light showers possibly sitting over Rapid city when viewed by
Satellite. Some of those showers may move into Dawes county later
tonight or possibly lose energy and dissipate before then. Pops over
the northern half of Dawes county was kept at 18 percent or less to
communicate the slight chance of these showers making it into Dawes
county. A ridge begins to build into the Intermountain West later
tonight to keep the forecast area temporarily dry for the next 24
hours. A low pressure system off the West coast is expected to stall
over California but continually feed moisture into the Rocky
Mountain Region. By the late afternoon to early evening time frame
the first of a couple shortwaves is expected to impact the Rocky
mountain region for some possible thunderstorm/rain shower chances.
Our forecast area will have plenty of moisture to utilize by there
is some uncertain on how strong the synoptic support will be to
create the possibility of severe thunderstorms. The 12 and 15z runs
of the High-res models only place around 500 to 1000 joules for
areas east of the I-25 corridor. There`s only a few lobes of
vorticity thats expected between 00 and 03z Wednesday or Tuesday
evening/night so the coverage may be very isolated as the synoptic
support is kind of lacking underneath our weak ridge. To compliment
the lack of unstable conditions, 700mb temperatures will range
between 6 and 9C keeping the surface temperatures in the high 60`s
to low 70`s to also help subdue any convective initiation during the
day. However, looking at the Hi-res models composite reflectivity,
some want to keep showers going through Wednesday morning before the
Ridge takes back over to keep Wednesday relatively dry during the
day.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 338 PM MDT Mon Sep 21 2026

Southeastern Wyoming and Western Nebraska will be under
southwesterly flow aloft as a mid-level ridge begins to build across
the Central United States. With an embedded shortwave trough
propagating across the region Wednesday afternoon combined with
another surge of monsoonal moisture (PWAT again ranging within the
80th and 95th percentile), widely scattered showers and
thunderstorms will be possible, mainly south of I-80. However, no
severe weather is anticipated due to weak instability (MLCAPE ~100-
200 J/Kg) thanks to poor mid-level lapse rates. Temperatures look to
be around or slightly warmer than average, in the low to mid-70s
east of the Laramie Range and mid to upper 60s to the west. A weak
cold front is progged to move through SE Wyoming and the W Nebraska
Panhandle overnight Wednesday into Thursday, which may serve as a
focal point for more shower development into the evening hours.

On Thursday, an additional shortwave trough within the longwave
ridge pattern may result in another round of afternoon and evening
showers and thunderstorms, with slightly cooler daytime high
temperatures behind the front. With an effective bulk wind
difference of only 15-20 knots along with relatively weak
instability (MLCAPE < 500 J/Kg), no organized or severe weather is
expected, despite a post-frontal air mass characterized by dewpoints
in the low to mid-50s across the Panhandle and PWAT exceeding
the 90th percentile yet again. This is rather rare for late
September, but we will certainly take any moisture we can get
despite nothing widespread expected...

The flow regime becomes more zonal on Friday which turns off our
supply for the anomalously rich monsoonal moisture seen the previous
days (PWAT ~0.9"). This will decrease our chances for any meaningful
precipitation and will also be the start of a warming and drying
period into the weekend. We will have to monitor increasing fire
weather concerns into the weekend as long range ensemble guidance
suggests gusty, westerly winds mainly across SE Wyoming, combined
with daytime RH values of 20-25%. Not particularly concerned at this
time as we are still short of critical fire weather thresholds, but
will have to be monitored as we get closer given plenty of dry fuel
and further warming underneath the building ridge. High temperatures
this weekend look to be 5-10 degrees above average, perhaps reaching
80 degrees in areas east of the I-25 corridor.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1047 PM MDT Mon Sep 21 2026

Low CIGs and patchy fog will lead to flight category reductions
for much of the TAF period. Low clouds are apparent on satellite
moving quickly westward. Expect MVFR to IFR conditions to move
into BFF, CYS, and SNY soon, with reduced conditions expected
into Tuesday morning. There is still a possibility that CIGs
waffle back and forth between flight categories through this
period, but at least some periods of IFR to LIFR are expected at
CYS, BFF, AIA, and SNY. Confidence is lower at CDR, and a brief
dip into IFR due to fog development is possible (20% chance) at
LAR.

Expect this to clear from west to east Tuesday. CYS should
return to VFR mid morning, but western Nebraska may hold onto
reduced CIGs into the early afternoon. Southeast winds will be
on the increase Tuesday, with gusts of 20 to 30 knots Tuesday PM
and overnight at all high plains terminals. In Wyoming, a few
showers and thunderstorms will be possible in the late
afternoon and evening, moving out of the southwest. PROB30
groups have been introduced.

&&

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

&&

$$

SHORT TERM...MM
LONG TERM...NB
AVIATION...MN