Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

871
FXUS65 KCYS 311145
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
545 AM MDT Mon Aug 31 2026

.KEY MESSAGES...

- Shower and thunderstorms are expected later on Monday and into
  Monday night. Strong wind gusts and heavy rainfall possible.

- Drying and warming trend expected going into mid to late week
  with growing potential for elevated fire weather conditions,
  mainly north of Interstate 80.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 210 AM MDT Mon Aug 31 2026

As expected, pretty quiet weather early this morning with
decreasing cloudiness over the area and temperatures responding
by falling into the mid 50s just after midnight. Yesterday`s
convection underperformed with most of the area only seeing some
light rain showers and quite a bit of wind. Expect Monday to be
mostly low impact as we turn our attention to the upper level
trough and next monsoon push, located across south central
California and Arizona at this hour. This trough is trending
even slower than yesterday`s model runs, which is likely going
to impact what southeast Wyoming and western Nebraska experience
going into late this afternoon and into tonight.

Again, models are trending later in the day with the onset of
precipitation and possible thunderstorm activity...with most
synoptic models holding off until around sunset along the I-80
corridor. High resolution CAMs aren`t much better, with showers
and thunderstorms developing between 5 PM to 8 PM. Not only is
precipitation delayed due to the slow movement of the trough,
but models soundings show a very dry airmass in the midlevels
and aloft. This airmass will likely mix down to the surface to
some degree across central Wyoming where daytime relative
humidities may bottom out near 10% to 15%. This will likely
delay the precipitation even later into the evening hours and
cut down on QPF amounts. For this afternoon, expect mid to high
cloudiness to push north ahead of the trough later in the
day, with gradual, but slow, moistening of the midlevels. There
is some decent synoptic/mesoscale lift with this upper level
trough as it moves northward with good mid to upper level
diffluent flow, some low level convergence and CAPE values
between 300 to 600 j/kg. However, the dry air aloft and slower
movement has capped QPF amounts mainly below one half inch to
closer to 0.10 to 0.25 of liquid at best. All ensemble means
have lowered by about half of they were showing yesterday with
the 90th percentile now below a third of an inch (yesterday`s
00z run were close to 0.75). Understandably, WPC has pulled
back on their Slight Risk for excessive rainfall as even a
Marginal even seems questionable at this time given recent model
trends. Therefore, kept POP about the same but expect a "High
POP/Low QPF" event for most of southeast Wyoming and western
Nebraska tonight through early Tuesday morning. Otherwise,
temperatures will be seasonable today with highs in the upper
70s to upper 80s (warmest below 5000 feet) and a continuation of
breezy conditions across southeast Wyoming.

For Tuesday, all models in good agreement showing rain shower
activity ending between 900 am to noon as the trough axis lift
north and exits the forecast area by the early afternoon hours.
Drier air and a shortwave ridge axis will push into the area
behind the trough, allowing for a relatively pleasant Tuesday
with breezy westerly winds but highs returning to the mid 70s to
mid 80s. There is a chance this trough slows down even further,
which may keep unsettled weather and cloud cover over the
eastern plains through the afternoon, resulting in lower
temperatures. However, models have been consistent with the exit
of this feature, so kept the current forecast as is. Coolish
temperatures possible late Tuesday night with clearing skies as
lows dip into the 40s and low 50s along and west of Interstate
25, with mid to upper 50s further east. Drier weather will
likely extend into the middle of the week as all model soundings
showing quite a bit of dry air aloft above 600mb, which will
likely cap any daytime convection...even though the surface to
600mb level will remain relatively moist due to remnant surface
moisture across the plains.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 1155 AM MDT Sun Aug 30 2026

The long term period will feature a warming and drying trend as mid-
level heights rise over our region and the bulk of any forcing for
ascent remain to the north or west of our area. Tuesday will feature
a slight chance of late day showers and storms as moisture remains
trapped underneath the ridge and we remain in SW flow pattern (PWAT
around the 70-80th percentile), however coverage is expected to be
lower relative to today and Monday. High temperatures will again
remain close to climatology, with highs in the 80s east of the
Laramie Range and mainly 70s out west.

We begin to heat up on Wednesday and Thursday as the ridge axis
becomes focused closer to the Northern Great Plains. This will turn
our attention to potential fire weather concerns as long-range
ensemble guidance has signals for gusty winds and daytime RH values
ranging from 15-25% especially north of the I-80 corridor. Highs
will peak in the upper 70s to near 80 degrees west of the Laramie
Range on both days, with much of the Nebraska Panhandle soaring into
the low to mid 90s, which is still a few degrees short of record
highs.

As we end the work week and head into the weekend, the ridge begins
to amplify and establish itself over the Central and Southern Great
Plains, resulting in a containing trend of above-average temperatures
and primarily dry conditions. There are some signals of an
additional push of monsoonal moisture on Saturday and Sunday,
however confidence isn`t high enough at this time to mention any
widespread precipitation for the region.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 545 AM MDT Mon Aug 31 2026

A potent upper level trough with some subtropical monsoon moisture
is forecast to lift north and move across the northern Rockies later
this afternoon and tonight. Scattered showers, some thunderstorms,
and lower CIGS are expected into early Tuesday morning.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail today and into
this evening. Rain showers and thunderstorms will develop across the
Colorado mountains ahead of the upper level trough and move north
into the Interstate 80 corridor, mainly impacting KLAR, KCYS, and
KSNY before 09z. However, limited impacts are expected from this
activity with a low probability of thunder and very low (<10%)
probability for MVFR or lower conditions through tonight. Kept
showers in the forecast for now with PROB30 groups for the most
likely areas to see some thunderstorm activity. For the other
western Nebraska terminals, impacts won`t begin until after 12z
Tuesday.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...NB
AVIATION...TJT