Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

982
FXUS65 KCYS 241149
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
600 AM MDT Wed Jun 24 2026

.KEY MESSAGES...

- Numerous to widespread showers and thunderstorms are expected
  Wednesday through Thursday. There is an Enhanced Risk for
  severe thunderstorms over the eastern plains, mainly along and
  east of Interstate 25, including western Nebraska.

- Very large hail (up to 4 inches in diameter), strong damaging
  winds, and a few tornadoes are possible Wednesday afternoon
  and evening.

- Thunderstorms Wednesday and Thursday will also increase the
  flash flood potential, particularly over recent burn areas.

- Warming temperatures, falling humidity, and increasing winds
  will increase fire weather concerns this weekend into early
  next week.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 204 AM MDT Wed Jun 24 2026

Yet another active day expected for Wednesday, and possibly
Thursday, with deep low to midlevel moisture remaining over the
area. For early this morning, last night`s thunderstorms have
moved southeast into northeast Colorado with some activity
remaining near Sidney as of 300 AM. Low clouds and some fog have
formed behind this thunderstorm activity as low level winds
shift into the east and southeast early this morning. Already
observing visibility between 1 to 3 miles in patchy fog and
dewpoint climbing into the mid 50s, which will set the stage for
a busy afternoon and evening. Over the next 6 hours, should be
relatively quiet as the low stratus and fog resulting in
boundary layer CIN of -200 to -400 j/kg over the area.

SPC has upgraded the area from a Slight Risk (2/5) to an
Enhanced Risk (3/5) Wednesday afternoon and evening over most
of the southeast Wyoming eastern plains and most of the western
Nebraska panhandle. In addition, the Marginal and Slight Risk
for excessive rainfall have been extended and increased in
coverage for training thunderstorms along a potent cold front
near the Colorado/Wyoming border in addition to any outflow
boundaries that run parallel to the mean flow aloft and surface
cold front. This may be one of the more active days in this area
for the past few years due to several severe weather concerns.
Model soundings and mesoscale analysis show PWAT values between
1.00 to 1.33 inches over a bulk of the area. A quick look at
NAEFS shows PWAT values, even for this time of the year, above
the 98th percentile and nearing the weekly maximum for 00z and
06z. Shear will be the least of our concerns with this event,
with all models showing plentiful 40 to 60 knots of 0-6km
shear (effective shear even higher). Impressive sounding
profiles with peak lapse rates within the primary hail growth
zone (0 to -20c or roughly 10k to 25k feet AGL) on both the GFS
and NAM soundings. As long as we break the cap, CAPE will be
plentiful in this set up with most models and ensemble guidance
showing MLCAPE of 1000 to 2000 j/kg and SBCAPE of 1500 to 2500
j/kg...even up to 3000 j/kg in the most unstable scenarios. Low
level wind shear is also present with a veering wind profile in
the lowest 2 km, which becomes even more impressive in the
vicinity of the surface cold front later this afternoon. The
only thing that may reduce the overall threat today will be the
large amounts of CIN early in the day, which may take a while to
erode. However, the forcing along the front should be
sufficient enough to break this cap in the afternoon, and this
may happen fairly quickly/suddenly. All models of severe weather
are possible, including tornadoes. Very large hail is also
looking more likely given the steep lapse rates in the hail
growth zone and the favorable shear profiles. Would not be
surprised to see a few softball-sized hail reports today.

If that wasn`t enough, concerns for flash flooding are
increasing, not only today...but for Thursday as well (even
though storm motion should be quicker on Thursday).
Thunderstorm cells that train southeast near the cold front and
slowly propagate and redevelop near outflow boundaries could
become a problem this afternoon and evening. Therefore, going
to start messaging the flash flood threat, very large hail
threat, and tornado threat more aggressively today.

For Thursday, along with the Flash Flood threat continuing due
to the cold front stalling near the I-25 corridor, there is a
slight risk of severe thunderstorms over most of the forecast
area. However, this risk may be more of a severe wind threat
with high res guidance showing several bands of squall lines
moving east across the area. WAA aloft near the front may get
this activity going early in the day with upslope flow remaining
near the surface, possibly as early as 300 to 800 AM up north.
In the afternoon, the HRRR shows what appears to be either a
strong squall line or derecho rapidly moving southeast over
southeast Wyoming and western Nebraska into the evening hours
with an impressive low level cold pool on 36 hour surface
analysis. Other CAMs show more in the way of individual bow echo
segments as the line move southeast, but not as continuous nor
as intense as the HRRR. Stay tuned for updates on a potential
strong (convective) wind threat for Thursday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Issued at 230 PM MDT Tue Jun 23 2026

Thursday...Westerly flow aloft continues, and with surface low
pressure developing over south central Wyoming producing a
convergence axis from Douglas to Laramie, and plenty of low and mid
level moisture, and 850/700 mb theta-e ridge axis from Casper to
Cheyenne, along with CAPE of 1000 to 1800 J/kg and bulk shear near
50 knots, we anticipate some storms to become severe, with large
hail and damaging winds as the primary threats east of I-25, with
some locally heavy rainers due to flow aloft.

Friday...Low amplitude ridging develops over our forecast area, with
some drier air noted advecting in. However, still expect isolated to
widely scattered afternoon and evening thunderstorms to form along a
low level convergence axis along the I-25 corridor. A few strong and
possibly severe storms may occur.

Saturday...The flow aloft turns southwest and increases in speed,
with considerably drier air moving across our counties, producing a
dry day with a warming trend as 700 mb temperatures spike near 19
Celsius.

Sunday through Tuesday...A broad trough aloft develops across the
northern and central Rockies, with dry southwest flow aloft, leading
to only isolated to widely scattered thunderstorms at most in the
afternoons and evening. Slightly cooler compared to Saturday in
the wake of a cold frontal passage.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 600 AM MDT Wed Jun 24 2026

Low clouds and patchy fog will continue early this morning, mainly
for the eastern plains of southeast Wyoming and western Nebraska.
These clouds/fog are expected to lift with another round of severe
thunderstorms possible for most terminals mid to late afternoon
through the late evening hours.

HAZARDS/WEATHER TRENDS: MVFR to IFR CIGS and fog will continue until
16z before lifting by 18z, mainly over KCYS and all of the western
Nebraska terminals. Thunderstorms will begin to develop between 19z
and 22z. Kept PROB30 groups for most terminals late this afternoon
and this evening (22z today to 05z Thursday) for showers and severe
thunderstorms. Will continue to add VCTS and TEMPO groups, and
possibly prevailing conditions, as coverage and timing becomes more
certain over the next few hours. Expect low CIGS and fog to
redevelop after 06z tonight after the thunderstorms are finished for
the night.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...RUBIN
AVIATION...TJT