Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

461
FXUS65 KCYS 231949
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
149 PM MDT Wed Sep 23 2026

.KEY MESSAGES...

- Cool but seasonable temperatures will continue through mid-
  week, with a warming trend expected for the weekend.

- Increasing coverage of showers and thunderstorms expected
  through Thursday as a subtropical disturbance lifts northward
  over the area, then a brief drying trend for the weekend.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 148 PM MDT Wed Sep 23 2026

Tonight...Almost a carbon copy of yesterday, with respect to the
moist low level airmass, as detected in surface analysis and with an
850/700 mb theta-e ridge axis extending north to south across far
southeast Wyoming with a low level convergence axis from Cheyenne to
Lusk. Much as depicted in the HRRR runs, which have been consistent,
leading to more believability, isolated to scattered showers and
some thunderstorms expected this evening south of a line from
Laramie to Alliance. Boundary layer saturation and pattern
similarity leads to moderate to high confidence in areas of fog,
dense at times, after midnight over the Nebraska Panhandle and far
eastern Wyoming.

Thursday...Once again, a moist low and mid level airmass exists
under weak flow aloft, with a low and mid level theta-e ridge axis
near the Colorado state line, thus with moist upslope east winds, we
anticipate scattered afternoon and evening showers, and isolated
thunderstorms south of a Rawlins to Chadron line.

Friday...Scattered showers and some thunderstorms will continue
early in the morning hours with a weak shortwave trough aloft over
the region. A somewhat drier airmass will advect across our
counties, effectively limiting shower and thunderstorm coverage,
though still cannot rule out widely scattered showers and
thunderstorms near the Colorado state line, and north of a Lusk to
Alliance line.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Issued at 148 PM MDT Wed Sep 23 2026

We begin the weekend on a warm and dry note as the primary surge of
monsoonal moisture lifts off to the north and east in conjunction
with the ejecting shortwave trough that has the chance to bring us
some beneficial moisture the day prior. This will result in well
above-average temperatures during the day, with forecast highs
anticipated to be 5-10 degrees warmer than climatology. For
reference, the average high for Cheyenne on September 26 is 68F
(yes, we are down into the 60s for averages now!) and 75F for
Scottsbluff. With the absence of any forcing throughout the day
thanks to the building ridge and 500 mb height rises, expect dry
conditions. Fire concerns are minimal at this time as 25th
percentile afternoon RH values are only expected to range from 15-
20%, however median peak gusts will be in the 20-25 mph range across
SE Wyoming. Further, fair overnight recoveries of 50-60% are
expected, keeping us below elevated fire weather criteria.

A similar pattern will remain in place on Sunday with above-average
temperatures and mostly dry conditions expected. Still, little to no
concern for fire weather as minimum RH values will stay well-above
20%. Long-range ensemble guidance is hinting at another influx of
monsoonal moisture being advected via SW flow on the western
periphery of the ridge, with PWAT values ranging from the 90th-95th
percentile relative to climatology. Deterministic runs show little
in the way of any synoptic-scale forcing for ascent to actually
utilize this anomalous moisture and translate it to precipitation at
the surface at this time, unfortunately.

Monday looks to be a bit more active than over the weekend as we
maintain the supply of monsoonal moisture out of the southwest.
NAEFS guidance has PWAT ranging from 2-4 sigma at this time, with
our region situated ahead a somewhat amplified positively-tilted
shortwave trough over the Great Basin. This should provide at least
some forcing for showers and thunderstorms heading during the day.
The threat for any heavy rain is uncertain at this time as the
forcing isn`t anticipated to be all that widespread, and although
PWAT will be on the high end of the distribution, we are getting to
that time of year where widespread and prolonged forcing gives us
our most beneficial moisture, rather than a single thunderstorm with
extreme rainfall rates that manages to sit over a localized area.
Unsurprisingly due to more moisture and therefore clouds/potential
precipitation, highs on Monday will be a bit cooler, though still a
few degrees above average. Although exact timing is highly uncertain
at this range, a cold front looks to push across SE WY and the
Nebraska Panhandle sometime during the day on Monday, which will
decrease our temperatures as we head into the middle of next week.

The shortwave trough skirts across the area on Tuesday, placing us
in more of a WNW flow regime. This will shunt off our supply of
subtropical moisture leaving us with drier conditions, especially in
the cooler, post-frontal air mass. Maybe our first actual taste of
fall that is long overdue? We shall see...


&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1135 AM MDT Wed Sep 23 2026

Fog and low clouds are in the process of mixing out across the
Nebraksa Panhandle this morning, and this trend is expected to
continue into the afternoon, with primarily VFR prevailing. KBFF and
KSNY are currently under MVFR CIGs, however cloud bases are expected
to increase to VFR criteria within the next few hours. Kept a PROB30
group for -TSRA at KCYS this afternoon where confidence is highest
that showers and thunderstorms will directly impact the terminal,
however much lower confidence that KLAR, KBFF, and KSNY will be
impacted. Thus, have opted for VCSH for these areas where coverage
is expected to be lower. While not as prevalent as the previous
couple of days, can expect more low cloud/shower development
starting overnight and carrying into the morning hours, primarily
for the NE terminals, where MVFR CIGs are anticipated in the
vicinity of any showers.

&&

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

&&

$$

SHORT TERM...RUBIN
LONG TERM...NB
AVIATION...NB