Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

436
FXUS65 KCYS 270804
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
204 AM MDT Mon Jul 27 2026

.KEY MESSAGES...

- A plume of monsoon moisture will arrive on Monday, moderating
  temperatures and improving rainfall chances through Wednesday.

- Marginal to Slight Risk of Severe Thunderstorms Monday through
  Wednesday. Strong gusty winds will be the primary threat.

- Heavy rainfall and localized Flash Flooding possible Tuesday
  through Wednesday night.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 1251 AM MDT Mon Jul 27 2026

Current KCYS radar loop shows a few bands of showers and
embedded thunder lingering across the western Nebraska panhandle
at 200 am, with some more isolated activity located near the
mountains of southeast Wyoming. This set up will likely continue
over the next several days with a decent monsoon push underway
over Wyoming, Colorado, and Nebraska. Low to midlevel moisture
advection will continue into Monday with PWATs increasing to
1.00 (west) to as high as 1.60 inches (east). This moisture
will likely remain over the area through Wednesday with all
models in good agreement, showing PWATs as high as 1.75 inches
for the eastern plains. NAEFS remains between the 90th to 98th
percentile for PWAT compared to climatological norms for late
July, which is pretty impressive considering late July/early
August typically experiences monsoon rainfall. Showers and
thunderstorms are expected each day through Wednesday afternoon,
and some of this activity could linger into the overnight hours
like we are experiencing early this morning.

With the arrival of higher moisture, slightly cooler temperatures
are expected over the next few days. We will likely have a brief
pause in the 100 degree temperatures with high and low
temperatures closer to average for this time of the year
(low/mid 80s along and west of I-25/upper 80s and low 90s east
of the I-25 corridor). However, considerable cloud cover might
keep low temperatures slightly elevated. Tuesday should be the
"coolest" day with highs in the mid 80s to low 90s across most
of the area, coolest along the I-80 corridor where the best
chance for showers and thunderstorms will likely be.

As for thunderstorms, SPC has upgraded the Marginal risk for
severe thunderstorms to a Slight Risk for about half of the
western Nebraska panhandle for Monday afternoon and evening.
Primary threat will be strong gusty winds over 70 MPH with a
small large hail threat since inverted-V soundings will still
be present for much of the day, but gradually moistening of the
boundary layer should occur late in the afternoon and through
the evening hours. Not much shear today with mainly straight
hodographs, especially later in the day, which favors straight
line winds. A few of these lines of storms may become organized
enough to produce some marginally large hail, but believe that
will be very isolated. Also, upper level short wave feature
appears to move relatively quick today, exiting the region as
early as mid to late afternoon. So not very confident about long
duration lines of thunderstorms at this time, but isolated weak
cells may still produce isolated areas of very strong wind
gusts in this set up. For Tuesday and Wednesday, a branch of the
70kt upper level jet to our north will sneak into the forecast
area, this feature will likely provide increasing upper level
forcing, but more importantly, increasing midlevel shear.
Models also show the next shortwave feature moving east much
slower around the periphery of the upper level high. This vort
max could be pretty potent as it tracks southeast across the
area, so would not be surprised if thunderstorm activity linger
past midnight Tuesday night/early Wednesday morning. Similar
conditions are expected on Wednesday with a better defined potent
Pacific upper level trough (for this time of the year anyway)
tracking across the Front Range. Flash Flooding will also become
more of a concern on Tuesday and Wednesday due to training/slow
propagation of storms and PWAT approaching 1.75 inches. Large
hail looks slightly more favorable by midweek, but the 0c to
-20c layer still looks rather elevated and sub-optimal.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Issued at 323 PM MDT Sun Jul 26 2026

Higher probabilities of afternoon showers and thunderstorms will
characterize the first portion of the long-term forecast period as
an enhanced push of monsoonal moisture moves through southeast
Wyoming and western Nebraska. Both ECMWF ensemble and GEFS ensemble
guidance show PWAT normalized anomalies peaking near the 2 standard-
deviations threshold through Wednesday afternoon. PWAT values
between 1 inch and 1.25 inches are seen in forecast soundings
during the afternoon hours. Additionally, a bit of enhanced
westerly flow aloft in the 500-200mb layer will round the apex
of the monsoonal ridge over the southwestern CONUS. This
enhanced flow aloft, while certainly not extreme, will be just
enough to add a bit higher bulk shear values to the convective
setup. Convection will likely develop over the higher terrain
of southeast Wyoming and drift east-southeastward by 18-20z. As
outflow boundaries pool, expect a chance of isolated gusty
winds perhaps occasionally to severe limits of 50 knots in the
eastern high plains of Wyoming and western Nebraska. While
temperatures will run slightly cooler the enhanced monsoonal
moisture, deeply mixed afternoon forecast soundings continue to
support a gusty wind threat. Thunderstorms should have enough
forward momentum to limit the risk of flash flooding. However,
any location that does see repeated rounds of showers and
thunderstorms could experience brief flash flooding concerns.

By Thursday, the monsoon high pressure over the southwest becomes a
bit more suppressed and the plume of higher moisture values drifts
eastward away from the Rocky Mountain region. As a result, expect
lower chances of afternoon showers and storms from Thursday through
next weekend. High temperatures will rebound somewhat as we dry out,
but some uncertainty in the temperature and precipitation forecast
emerges by the weekend. A frontal boundary from the northern high
plains attempts to drop southward into the eastern plains of Wyoming
and western Nebraska perhaps as early as Friday afternoon. Ensemble
guidance varies greatly with regard to any impacts...ranging from
only slightly cooler temperatures to a frontogenetically forced band
of showers and cloud cover over the high plains on Friday evening,
or perhaps on Saturday. With such low confidence from Day 5 onward
in the forecast, we will message a more conservative outcome for now
with slightly less hot weather and isolated shower chances.
Regardless, significant precipitation seems unlikely through the end
of the long term with generally above-average temperatures
continuing for the foreseeable future despite a few frontal
boundaries nearby.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1122 PM MDT Sun Jul 26 2026

A few lingering showers and thunderstorms are trekking through,
impacting KBFF, KCDR, and KAIA for the next few hours. Otherwise,
VFR conditions will prevail across all terminals throughout most
of this TAF period. Expect benign conditions through the
overnight hours across all the sites with variable winds
generally 6 knots or less. Another surge of moisture will begin
to push into the area by 18Z Monday, increasing the chances of
showers and thunderstorms across all the terminals. Right now,
for this forecast period, the best chances of thunderstorms look
to impact KCYS, KLAR, KBFF, and KSNY. Elsewhere, confidence is
lower and therefore kept it VCSH in this TAF issuance.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...MAC
AVIATION...RZ