Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

757
FXUS65 KCYS 201755
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1155 AM MDT Wed May 20 2026

.KEY MESSAGES...

- Chilly temperatures will continue for the next several days.
  Another round of freezing temperatures expected this morning
  in areas with snow cover, with patchy frost and fog elsewhere.

- Isolated to scattered showers and a few thunderstorms will
  continue through Wednesday night. A more widespread round of
  showers and thunderstorms expected Thursday into Friday.

- Slightly above average temperatures and pleasant weather
  expected for the weekend.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 215 AM MDT Wed May 20 2026

Current KCYS radar loop shows some light rain showers with a
little bit of snow above 7500 feet across the far southeast
Wyoming near Cheyenne and Pine Bluffs and the southern Nebraska
Panhandle early this morning. The upper level trough axis near
the Utah border and WAA aloft out ahead of it is responsible
for this activity. Periods of light rain showers will likely
continue this morning and into the early afternoon hours with
breaks at times. Watching some fog across the I-80 Summit also
and will likely need a Dense Fog Advisory shortly since the
precipitation appears to have shifted to the east. Southeast
winds should continue for the next 6 hours over the Summit, so
do not expect the fog to lift until midmorning. Otherwise,
Freeze Warnings and Frost Advisories continue for most of
southeast Wyoming and Sioux County over western Nebraska.

Slow warming trend will continue for today and Thursday as a
long wave trough settles into the western third of the United
States. Carbon county will rebound today with highs in the upper
40s to middle 50s with recent webcams showing rapid snow melt.
There are still areas with deep snow pack, and those locations
will likely still make it into the middle 40s. Kept 20 to 40
percent POP for this afternoon with some weak WAA aloft
continuing through the day but better instability should keep
widely scattered rain showers and isolated thunder going through
this evening. Not as cold tonight with lows in the 30s to low
40s across most of the high plains, and upper 20s to low 30s for
Carbon and Albany counties.

Later on Thursday, models show a potent clipper system digging
south out of Alberta Canada and slowing down over the region.
Will have to monitor this system for additional mountain
snowfall, but expect most of the lower elevations to stay as
rainfall. The system has trended a little colder compared to
yesterday, with rain/snow mix down to 6500 feet...but any
accumulations should be minimal for Laramie and Rawlins with
generally no impacts on area roadways. Good low to midlevel
forcing with this system, and daytime instability will aid in
shower and thunderstorm development with CAPE values between 400
to 800 j/kg. Could see some decent rainfall amounts into
Friday, with 25th to 50th percentile QPF amounts between a
quarter inch and half inch. Some places across western Nebraska
could even see up to 1 inch of rainfall from this system
depending on the coverage of deep convection. Increased POP
above 75 percent for most of the area with the good chance for
another much-needed wetting rainfall.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 139 AM MDT Wed May 20 2026

An active and summer-like weather pattern is expected to take shape
Friday through most of next week. Upper-level trough continued
Friday and Saturday before zonal flow returns for Sunday and Monday.
The next best chance for upper-level troughing looks to be Tuesday
through the end of the week as a deep, upper-level trough near the
West Coast pushes eastwards through mid-week. The 500mb flow will
feature a very similar progression throughout the next several days,
but isolated vorticity lobes will pass across the CWA, leading to
increasing synoptic ascent despite the largely zonal upper-level
flow and large-scale ridging late in the week. Westerly to
southwesterly flow will dominate at 700mb Friday through much of the
upcoming week, with moisture continuing to advect in with the 700mb
from the Pacific Ocean just southwest of southern California.
Despite the influx of moisture, the NAEFS Mean suggests that
Precipitable Water values will remain seasonal for this time of
year, so significant rainfall is not expected at this time though
still likely more than the region has seen throughout much of this
"winter" season. Looking at 700mb temperatures, a warming trend is
expected Friday through much of the week, with 700mb temperatures
over 10C returning for much of the region early next week. Surface
temperatures will also see a warming trend through the weekend and
into next week, with a small potential for slightly warmer than
average temperatures, favored by the NAEFS Mean 700mb Temperatures
being in the 90th percentile for isolated portions of the CWA.

While every day in the longer term forecast will feature some chance
for isolated, afternoon showers and storms, as is quite typical with
a summer-like pattern, Friday looks to be the most active day with
the best potential for isolated, strong to severe thunderstorms. The
next best day for precipitation will be Wednesday as the next upper-
level trough is progged to push into the region. Looking at Friday,
a messy, 700mb low will slowly get its act together in the morning
hours becoming a closed low by late morning. An attendant surface
low will push northeast out of northeastern Colorado, placing the
CWA on the cooler side of the system as a whole. However, 700mb warm
air advection is expected to start by the early afternoon hours as
warmer temperatures further south start to push north as the first
upper-level short-wave trough move off to the northeast and the
second slowly swings across the Intermountain West for the overnight
hours. Therefore, during the day, there will be favorable ascent in
the form of 500mb vorticity maxima moving across the region combined
with 700mb WAA, residual ascent associated with the surface low,
then finally a secondary, weaker cold front as the second short-wave
pushes through the region overnight Friday into early Saturday
morning. Hires guidance does not quite reach Friday afternoon and
evening at this time, but the NAM suggests anywhere from 200 to 700
J/kg of MUCAPE across the western Nebraska Panhandle. This would be
enough, combined with the synoptic ascent across the region, to get
at least a few rumbles of thunder, but also the possibility of very
gusty winds and possibly some isolated hail. It will be interesting
to see how hires guidance depicts this system as it gets into the
time range, especially since forecast NAM soundings suggest a very
wet environment with very strong 0 to 3km shear.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1145 AM MDT Wed May 20 2026

Low cloud cover over the High Plains is breaking up this
afternoon with gusty southerly winds continuing. Scattered
showers will continue until about 00z to 02z, with a few rumbles
of thunder possible as well. PROB30 groups are present for all
High Plains terminals to handle this possibility. Gusty
southerly winds will continue overnight tonight. During periods
of lulls in the wind at the surface, expect to find significant
LLWS.

Moisture return overnight will also promote another round
of low clouds and/or fog. Confidence is highest in IFR
conditions at CYS and SNY, with MVFR most likely at BFF and
AIA. A reduced flight category cannot be ruled out at LAR. This
should clear by late morning ahead of a more widespread round of
showers and isolated thunderstorms moving in from the west
towards the end of the TAF period.

&&

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

&&

$$

SHORT TERM...TJT
LONG TERM...AM
AVIATION...MN