Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

393
FXUS65 KCYS 201740
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1140 AM MDT Mon Jul 20 2026

.KEY MESSAGES...

- Hot, dry, and breezy conditions continue through Monday.

- Monsoonal moisture will attempt to return by Tuesday resulting
  in increased precipitation chances through much of the week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 221 AM MDT Mon Jul 20 2026

One more hot day is expected on Monday as the upper-level ridge sits
directly over Wyoming. Most locations across the area will see highs
in the 90s to low 100s, which is about 5 to 10 degrees above average
for this time of year. Heat Advisories remain in place for portions
of southeast Wyoming and western Nebraska through 6 PM this evening.
Hot temperatures will lead to dry conditions at the surface, though
a weak disturbance moving through the ridge could spark some showers
and thunderstorms as PWATs remain elevated due to a push of monsoon
moisture. Hi-Res guidance shows a few showers developing early in
the afternoon, with coverage increasing into the evening hours.
Severe storms are unlikely, however, cannot rule out an isolated
severe wind gust with DCAPE values over 1600 J/kg. Brief heavy
rain will also be possible in showers and storms as monsoon
moisture bumps PWATs closer to 1 inch. Some models are hinting
at the potential for some isolated nocturnal convection as well
as some surface based CAPE will exist. However, it seems that
Hi-Res guidance is starting to decrease overnight storm chances.

A shortwave digging down from Canada will send a cold front across
the area Monday night. Temperatures on Tuesday will be noticeably
"cooler", falling about 10 degrees compared to Monday`s highs.
Increased moisture into the area from a proper surge of monsoon
moisture will lead to increasing cloud cover throughout the day.
Instability and PWATs in the 90th percentile will lead to storm
development during the afternoon hours. Hi-Res guidance shows
widespread showers and storms developing west of the Laramie Range.
Cloud layer winds are on the slower side per model soundings. Slow
storms combined with high PWATs will lead to a heavy rain threat
with the potential for flash flooding. Showers are likely to
continue into the overnight hours and spread eastward with the heavy
rain threat also spreading eastward.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 1250 PM MDT Sun Jul 19 2026

Monsoonal moisture arrives in bulk to southeast Wyoming and
western Nebraska by Tuesday and will last throughout much of the
long-term period. The primary reason for the increase in monsoon
moisture will be a lobe of enhanced PWAT values, originating
from the eastern Pacific in the vicinity of a decaying tropical
system drifting north. This, combined with a more favorable
position of the ridge over the southern Four Corners region,
will direct more saturated profiles eastward across the Great
Basin and through the I-80 corridor. After a slight increase in
thunderstorm coverage and chances on Tuesday, the peak of this
surge of moisture will arrive for the convective afternoon
timeframes on Wednesday and Thursday when PWAT normalized
anomalies exceed the 75th percentile of climatology. The
thermodynamic setup combined with relatively light wind speeds
aloft will favor some slow storm motions. Flash flooding will be
possible in areas that see repeated rounds of thunderstorms or
any storms that remain stationary for long periods of time. For
now, the best chances of this appear to be in the higher
elevations of southeast Wyoming as well as the adjacent
foothills of the Snowy, Sierra Madre, and Laramie ranges.
Ultimately, outflow boundary interactions will ultimately
determine where the heaviest rain falls - details that generally
can not be anticipated until the day of the event. Overall,
expect afternoon high temperatures to drop back notably thanks
to increased cloud cover and slightly lower mid-level
temperatures from Tuesday through the end of the week. By Friday
evening and into early next weekend, ensemble guidance suggests
that the monsoonal push will drift eastward and lower PWAT
values will return to the Rockies/High plains. This may
ultimately result in lower precipitation chances and warmer
temperatures by next weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1124 AM MDT Mon Jul 20 2026

Ridging aloft will continue. Isolated to widely scattered
thunderstorms will develop this afternoon through early evening
from Rawlins to Cheyenne to Sidney, in a low level upslope
regime. Elevated convection in the form of widely scattered
thunderstorms will develop later tonight from Douglas to
Scottsbluff and Alliance.

Wyoming TAFS...VFR prevails. High confidence due to the models
as well as the HRRR showing isolated to widely scattered
thunderstorms developing from 21Z to 03Z, though spatial
coverage only warrants VCTS at this time until convection
develops further. Typical gusty winds until sunset, and after
15Z Tuesday at Laramie and Cheyenne.

Nebraska TAFS...VFR prevails. With the HRRR and the models
showing isolated to widely scattered thunderstorms developing
this afternoon and evening, high enough confidence to include
VCTS at Scottsbluff and Sidney from 00Z to 03Z. HRRR and
positioning of the east to west 850/700 mb theta-e ridge axis
and surface discontinuity suggests widely scattered elevated
late night thunderstorms developing from Douglas to Scottsbluff,
and with spatial and areal coverage still in question, went
with VCTS only at Chadron, Alliance and Sidney from 06Z to 14Z.
Expect typical gusty winds until sunset, and after 15Z Tuesday
at Sidney.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Heat Advisory until 6 PM MDT this evening for WYZ101-102-108.
NE...Heat Advisory until 6 PM MDT this evening for NEZ002-003-
     019>021-095-096.

&&

$$

SHORT TERM...SF
LONG TERM...MAC
AVIATION...RUBIN