Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

436
FXUS65 KCYS 311145
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
545 AM MDT Sat Oct 31 2026

.KEY MESSAGES...

- Intermittent, locally dense fog Saturday morning will clear
  out by midday. Another round of fog is possible Saturday night
  into Sunday morning.

- Mild conditions are expected for Halloween (Saturday), though
  a few showers will be possible along and west of I-25.

- A complex but disorganized storm system will move into the
  area Sunday, bringing cooler temperatures and a chance for
  rain and high elevation snow showers.

- A second round of precipitation is increasingly likely to
  develop over portions of the High Plains Monday into Monday
  evening.

- Widespread blustery conditions are anticipated Monday into
  Tuesday along and east of the Laramie range.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 340 AM MDT Sat Oct 31 2026

Spooky fog has settled in over portions of the High Plains to start
this Halloween. This morning`s fog is a bit more intermittent
than yesterday, but at least patchy fog encompasses much of the
High Plains. Expect fog to roll in and out a few times this
morning. Dense Fog Advisories have been posted for much of the
I-25 corridor and portions of the I-80 corridor, but may need to
be expanded if fog pushes into the central/northern panhandle
as well. Cloud cover and abundant low-level moisture are
supporting very mild temperatures for this time of year, with
today expected to start off in the upper 30s to mid 40s for all
areas. The vort-max moving into the area out of the southwest is
a bit ahead of schedule, as mid to upper level moisture is
already pushing into southern Wyoming as indicated by GOES water
vapor imagery. Expect shower activity to kick up over the next
several hours, mainly in Carbon county, but rainfall amounts
will be minimal. We actually have a fairly dry airmass in place
west of the Laramie range, but expect dewpoints to rise as light
rain falls into the dry boundary later. The shortwave trough
axis should push through around midday, decreasing coverage of
shower activity afterwards, though some shallow instability
should keep isolated showers going along and west of the Laramie
range through the early evening hours.

This year`s trick-or-treat forecast is unusually mild. Sunset
temperatures will be generally in the 50s, dropping to the mid 40s
to around 50 by 9PM. Aside from a few light showers around,
conditions should be pleasant with generally light winds. While
portions of Carbon and Albany county will be breezy during the
daytime hours, expect this to weaken by the evening.

Sunday will be a transition day as a complex storm system approaches
from the west. Southwest flow aloft will support the advection of
very deep tropical moisture. Precipitable water is expected to surge
rapidly through the day Sunday pushing close to climatological
maximums by the end of the day. With the aggressive moisture
advection, we should see mostly cloudy skies over most of the area,
and thus temperatures a few degrees cooler than Saturday. Forcing
for ascent will push in Sunday morning in the form of positive theta-
e advection and isentropic ascent. This looks most prominent
along and west of the Laramie range as it will take a little
longer to reach saturation further east. Expect numerous to
widespread showers in Carbon County through much of the day,
which will gradually push east into at least Albany and Converse
counties later in the day. Further east, rainfall will be more
spotty, with little to no rain expected in far southeast Wyoming
and the central/southern Nebraska panhandle. With falling
surface pressure over southwest Wyoming during this period,
expect breezy south to southeast winds over much of the area
during the day Sunday. Lift is expected to shut off sometime
between sunset and midnight Sunday evening as the axis of the
first mid-level shortwave trough swings through the area. This
will put much of the area in a lull Sunday night into Monday
morning.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 340 AM MDT Sat Oct 31 2026

The approaching storm system continues to look rather messy.
Multiple competing upper level lows will make for a muddy forcing
picture across the region. A deep primary trough will be making its
way across the western CONUS while a moisture laden upper level low
riding the sub-tropical jet races in around it. The primary 700-mb
low and the secondary center associated with the subtropical system
will both pass through the area Sunday evening, leading to drier
conditions over much of the area Monday morning. After passing our
area, these two should consolidate into one system and stack on top
of a rapidly developing surface cyclone. This should take over
around daybreak Monday, setting up a strong pressure gradient over
the High Plains and leading to increasing northwest winds Monday
morning. Widespread gusty northwest winds can be expected Monday
into Monday night over the High Plains. Confidence remains high in
fairly widespread gusts of 45 to 55 mph, with still some potential
to exceed High Wind criteria. Probabilities are generally around 30
to 40% for all along and east of the Laramie range, including the
wind prone areas around the I-80 summit and I-25 between Wheatland
and Glendo. The wind direction is not very favorable for high winds
at Bordeaux. The lack of vertically stacked westerlies and potential
for synoptic ascent rather than descent as surface winds increase
decreases confidence in widespread high winds.

Forcing will not really favor much lift during this period Monday
AM, so expect fairly limited coverage around dawn, but this should
change as the day progresses. Model guidance is now in fairly good
agreement showing the mid-level low pressure elongating back to
the southeast after it passes through our area. This will be
forced by lee cyclogenesis ahead of the the primary upper level
low swinging over the Four Corners which begins to slow down as
it ejects to the east. This appears to be a very complex
evolution, but the end result is to turn the wind direction in
the 700 to 500-mb layer from northwest Monday morning to north
or even northeast by Monday afternoon. Despite surface downslope
northwesterly winds continuing, we may see support for ascent
just above the surface layer. Where northwest flow is not as
unfavorable (Douglas to Chadron corridor), seeing an increase in
appreciable rainfall is more promising. The surface downslope
will be tough to overcome around the Cheyenne to Sidney
corridor. Thus, we appear to be finally converging on the
scenario with moderate precipitation in our northern zones, and
more limited precipitation further south.

The latest QPF probabilities reflect the increasing confidence in
this scenario. LREF probabilities for 0.5" or more of liquid
precipitation are around 50 to 60% in Rawlins, Douglas, and Chadron,
which look like the most favorable areas at this time, though it is
worth mentioning that at least for Rawlins some of this will come
from the first phase Sunday and Sunday night, with a break early
Monday morning, and then another round Monday late morning into the
evening. Precipitation evolution may take on the character of
typical northerly flow events across our area, with the subtle
terrain features of the High Plains becoming unusually prominent.
Specifically, look for more precipitation along the north sides
of the Pine Ridge and Cheyenne ridge, with lower totals into
the Wheatland to Bridgeport corridor and I-80 corridor
(including Cheyenne) and points southward. Laramie and the I-80
summit will be an area to watch for greater uncertainty. This
is a pretty unusual synoptic setup with veering winds above
surface northwest winds, but that surface direction is favorable
for increased precipitation around the city of Laramie.

The last piece of the puzzle with this storm system will be snow
levels. Snow levels will be fairly high for most of the event,
especially during the first phase where rain may fall as high as 9
to 10 kft. However, we can expect gradual advection of colder air
during the day on Monday to reduce snow levels. By sunset, 700-mb
temperatures should be below 0C over most of southeast Wyoming. As
precipitation picks back up midday Monday into the evening, rain may
change over to snow between 5000 ft and 8000 ft. The precise snow
level will probably depend on the precipitation rates, with areas of
heavier precipitation changing over faster, while lighter rates stay
as rain. The problem with this is that there is considerable high
end boom scenario potential on snow accumulation if a given area
flips over faster than expected. The primary areas to watch right
now are Douglas, Lusk, Harrison, and possibly Laramie and the
Chugwater area. For now, no snow accumulation is in the official
forecast because this is still a low-probability (30% chance) but
high impact scenario. However, snow levels were blended to the NBM
10th percentile to ensure the mention of snow is included for these
areas of concern.

A much drier airmass will rotate into the area after midnight Monday
night, bringing an abrupt end to precipitation from north to south.
Gusty northwest winds will continue into Tuesday, but temperatures
should rebound to near seasonal averages. The remainder of the week
looks to remain somewhat unsettled, with a series of moisture-
starved upper level lows pushing across the region. Low-end chances
for light precipitation will be present with temperatures near
seasonal norms. If some of these lows track slightly to our north,
we may have to watch for some gusty winds in the wind prone areas,
but most ensemble members keep winds light during this period. By
the end of the week into the weekend, we may have another closed low
tracking across the west to keep an eye on. Uncertainty is extremely
high at this lead-time, but about 1/4 of ensemble members have a
closed upper level low tracking over the right area to bring
widespread precipitation to the area. However, the remaining 3/4
members are either dry or with minimal precipitation.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 541 AM MDT Sat Oct 31 2026

Low CIGs and areas of fog remain the primary aviation concern
today. This round of fog is proving to be more intermittent and
harder to pin down than the last previous few days. IFR to LIFR
is expected to prevail through mid morning at CYS, AIA, and SNY,
with greater uncertainty at BFF where fog may spill back into
the terminal shortly. TEMPO groups for waffling visibility are
included for these terminals, as we may not stay put at one
flight category.

Trends should be towards MVFR by late morning or early
afternoon, with breaks of VFR expected at all terminals except
perhaps AIA this afternoon. Another round of low clouds and fog
will surge in this evening into early Sunday morning.

At LAR and RWL, look for winds to turn southwest and
occasionally gust 20 to 30 knots. In addition, a few showers may
be in the area much of the day today, clearing out after
sunset.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Dense Fog Advisory until 10 AM MDT this morning for WYZ101-107-
     117>119.
NE...None.

&&

$$

SHORT TERM...MN
LONG TERM...MN
AVIATION...MN