Chadron, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

919
FXUS65 KCYS 311721
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1021 AM MST Wed Dec 31 2025

.KEY MESSAGES...

- High winds remain possible in the Arlington/Elk Mountain wind
  prone zone through the morning.

- Another round of high winds remains possible Thursday morning,
  with a third round possible on Friday.

- Above average temperatures, breezy conditions and a chance of
  precipitation primarily in the mountains expected through
  early next week, with a pattern change possible late.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 213 AM MST Wed Dec 31 2025

Mostly quiet for the next with days with gusty winds and mountain
snowfall. Upper-level flow will be largely dominated by a building
ridge across the Intermountain West today through much of Thursday
before a transitional pattern sets up for Friday onwards. For today,
upper-level ridging will build into the area leading to
predominantly northwesterly flow aloft and clear skies. A weak
500mb vorticity max looks to push into southwestern portions of the
CWA this after, so clear skies are expected to turn partly cloudy
west to east across the CWA. 700mb flow will remain mostly
northwesterly throughout the day, with a brief amplification of the
height gradients across and just west of the Laramie Range through
about 15Z this morning. A fairly strong surface pressure gradient
will set up both across the Arlington/Elk Mountain wind prone zone
and the Laramie Range near the Bordeaux wind prone area. The surface
gradient across both zones will max out around 4mb, leading to some
breezy gap winds across these zones through about 15 to 18Z, when
the surface gradient weakens. 700mb flow will be fairly week across
these zones and will max out around 40kts. Modest to strong GFS
downward omega values should allow some of these 40kt winds to mix
down to the surface through the morning hours, with downward
acceleration from gravity potentially leading to a few gusts 50+kts
in these zones. The High Wind Warning and High Wind Watches remain
in effect to cover this early to late morning threat. However, in-
house random forest guidance keeps fairly low probabilities of high
winds through the morning, but a few gusts 50+ kts cannot be
completely ruled out when downward acceleration is considered.

Aside from the gusty conditions today, 700mb temperatures will warm
into the 3 to 5C range this afternoon, which is above the 90th
percentile according to the NAEFS climatological percentile. With
additional downslope warming, today will be another balmy day as
temperatures increase into the low- to upper-50s east of the Laramie
Range and mid-40s to low-50s west of the Laramie Range. Downslope
winds will also lead to drier conditions, so precipitation is not
anticipated today, especially with little to no synoptic lift aside
from weak 500mb cyclonic vorticity advection. With the dry and gusty
conditions, elevated fire weather conditions are expected this
afternoon for the I-80 corridor east of the Laramie Range and
Cheyenne areas. Did not issue any fire weather headlines as the
minimum afternoon relative humidity looks to remain above critical
thresholds with only a few gusts 30+ mph possible in this area.
However, still use caution if conducting any outdoor burning.

Upper-level ridging continues into Thursday, though an upper-level
trough moving into the western CONUS will start affecting the
region. Largely northwesterly flow is expected Thursday as the ridge
remain aloft, but starts to weaken through the afternoon and evening
hours. A fairly strong vorticity maximum looks to eject out ahead of
the incoming trough along with a diffuse shortwave, leading to
amplified synoptic lift across western portions of the CWA starting
Thursday morning. These two factors will act together to start
increasing mountain snowfall potential Thursday morning into the
afternoon hours. Southwesterly flow at 700mb will further favor
upslope development along the Sierra Madre Range and Snowy Range
throughout the day Thursday. The NAEFS Mean IVT suggests a brief
increase in IVT values 18Z Thursday along the Sierra Madres,
increasing confidence in decent snowfall rates for the mountains.
NAEFS Mean Precipitable Water values also look to be above the 99th
percentile to the maximum percentile across the Sierra Madres from
12Z Thursday through 12Z Friday. Therefore, a decent snowfall event
looks to be taking shape for the Sierra Madres, with a current
forecast of 10 to 13 inches for the Sierras and 5 to 8 for the Snowy
Range. Decided to hold off for now on issuing winter weather
headlines to allow day crew to take another look at the overall
setup and snowfall potential for the mountains.

Another potential high wind event for the typical wind prone regions
looks possible on Thursday, as 700mb winds increase to around 40 to
45kts. Surface pressure gradients across the Arlington wind prone
area and Bordeaux wind prone area will increase early Thursday
morning to around  3 to 4mb once again. 700mb will be a bit stronger
for this event with slight strong downward omega values being
modeled by the GFS as compared to today. In-house random forecast
guidance is also pinging this event a bit harder, with probabilities
of high winds in the Arlington and Bordeaux wind prones around 40%.
Decided to hold off issuing any high wind headlines to let future
shifts take another look at models for this event. However, it does
look to be quite breezy again Thursday morning. Along with this,
downslope warming is expected again, leading to another warm day
Thursday with highs in the low- to upper-50s once again east of the
Laramie Range and low- to mid-40s west of the Laramie Range.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 213 AM MST Wed Dec 31 2025

No major changes to the long term forecast. Please see previous
discussion...

Long term will be semi-active as an upper level low pressure system
moving inland from California weakens and moves across the Four
Corners region, helping to disrupt the high pressure ridge
controlling the area. While this ridge should then re-establish into
the weekend, multiple systems will then begin riding the periphery
of this feature, helping to begin slowly shifting and weakening it
through the end of the forecast period, keeping some sensible
weather concerns present for the CWA including winds and mountain
precipitation.

As mentioned, an upper level low moving inland will help to disrupt
the high pressure ridge holding control of the region in the short
term, allowing temperatures to stop their rising trend and hover in
the 40`s to 50`s for highs on Thursday and Friday.
Meanwhile we should see another brief increase in gusty winds, but
still uncertain if it will be strong enough to warrant a high wind
warning for our wind prone locations for Thursday. In house guidance
indicates only a maximum of around 50% probability for gusts 58+
mph, and will be mostly gradient driven as 700mb support will be
lacking. Still, knowing how our wind prone locations do like to over
perform, wouldn`t be surprised if we see another another round of
products. Friday the 700mb jet should briefly re-strengthen and this
combined with favorable surface pressure gradients will bring a
higher risk of strong winds for our wind prone locations, this time
with a slightly better probability (60-70%). Otherwise, this change
should bring a little more moisture to the area alongside westerly
to southwesterly flow, allowing for mountain precipitation to
develop. Without significant forcing this should mostly be
orographically forced in nature, with light to moderate snow in the
Snowy and Sierra-Madre ranges. Snowy range may be shadowed by the
southwesterly flow, but the Sierra-Madre range is currently forecast
to see enough snowfall Thursday into Friday to warrant an advisory
with around 6 to 10 inches possible.

Over the weekend and into early next week, the ridge will start to
re-establish, leading to a warmer day on Saturday with highs a few
degrees warmer than the end of the week, but multiple systems riding
the periphery of this feature will help to keep it slowly transient
through the end of the forecast period, while also beginning to
flatten the feature and keep our weather semi-active. Widespread
winds through the end of the period look to remain breezy (gusting
20-40 mph), but in house guidance isn`t as excited for any stronger
wind events currently. Meanwhile generally westerly to southwesterly
flow may fuel some light chances of precipitation in the high
terrain, but once again a lack of significant features and lower
moisture will preclude significant activity, with general light
mountain snow showers expected. Temperatures should start to fall a
few degrees each day though, keeping us above average as we move
into the first full week of the new year but not a widespread record
setting event compared to last week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1021 AM MST Wed Dec 31 2025

VFR conditions will prevail through the period. Winds will
mainly be westerly with all TAF sites seeing winds of 10 kts and
above with gusts to near 20-25 through 23Z. After 23Z winds will
turn more diurnal and range between 6-8kts. CIGs will be mostly
SKC through the period before giving way to high clouds of
25kft.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch until 11 AM MST this morning for WYZ106-116.
NE...None.

&&

$$

SHORT TERM...AM
LONG TERM...AM/CG
AVIATION...WFOCYS