Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

656
FXUS65 KCYS 241150
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
550 AM MDT Thu Sep 24 2026

.KEY MESSAGES...

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

- A brief drying trend expected for the weekend, ahead of a
  potential strong Pacific storm system moving into the Front
  Range early next week.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 210 AM MDT Thu Sep 24 2026

Pretty quiet early this morning as yesterday evening`s
thunderstorm activity has pushed well east of the forecast area.
Early morning temperatures are pretty mild due to the cloudy
skies across the region and south to southwest flow aloft
bringing in additional subtropical moisture. Did add some patchy
fog where some clearing is taking place, mainly over the
northern and central Nebraska panhandle with SREF and HREF
probability of fog (VIS below 4 miles) around 20 to 40 percent.
Otherwise, no other changes made to the forecast through noon
Thursday.

Models have continued to back off on rainfall and thunderstorm
chances for later Thursday and Thursday night. For much of
today, model soundings show stable low to midlevels with poor
lapse rates and hardly any instability until this evening...as
some cooler air aloft moves overhead. High res CAMS agree with
this solution and don`t show much activity until late this
afternoon and into he evening hours. Kept most of the area dry
with POP below 10 percent until this evening. All models in
better agreement showing the upper level disturbance, which is
responsible for the heavy rainfall across New Mexico and western
Texas, lifting northeast and ejecting east across the forecast
area. The best dynamics will be south and east of the northern
Front Range. The trough axis will also lift across the area late
Thursday night and Friday morning, with limited instability and
forcing. Lowered POP across the whole forecast area. Still
expect some scattered showers and isolated thunderstorm, but
this activity looks to confine itself to the I-80 corridor and
not even as far north as the North Platte River. However, any
heavy rain showers are not expected to move much tonight, so
can`t rule out a minimal excessive rain threat along the I-80
corridor especially with PWATs near the 95th to 99th percentile
for this time of the year. Increased max temperatures a few
degrees due to the lack of precipitation for most of the day.

All models show some drier air moving into central Wyoming as
low to midlevel winds shift into the west. However, models show
the upper level disturbance taking its time ejecting east.
Increased POP in the mountains and for areas along and east of
the Laramie Range Friday afternoon and evening for widely
scattered thunderstorms and periods of showers. All models show
better instability as well with the trough axis overhead and
dewpoints remaining in upper 40s to mid 50s ahead of the dry air
intrusion. Afternoon temperatures expected to be near seasonal
averages and generally in the upper 60s to upper 70s (warmest
below elevations of 4500 feet).

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 150 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 /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 550 AM MDT Thu Sep 24 2026

A subtropical upper level disturbance will slowly lift northward
across the Rocky Mountain region through Friday before ejecting
eastward. Mostly cloudy skies will continue with isolated showers
and thunderstorms. Areas of fog expected late tonight as this
disturbance lifts northward into the area.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail through
06z Friday. Some lingering early morning low CIGS possible near
KAIA, KSNY, and KBFF, but coverage is low enough to keep out of the
TAF. A few thunderstorms may form this afternoon and this evening,
but coverage will be very limited to along and south of the
Interstate 80 corridor. High confidence that low stratus and fog
will develop across the high plains late tonight after 06z Friday,
impacting KAIA, KSNY, and possibly KBFF and KCYS towards 12z Friday.

&&

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

&&

$$

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