Sidney, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

144
FXUS65 KCYS 282325
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
525 PM MDT Sun Jun 28 2026

.KEY MESSAGES...

- A few evening and overnight showers and thunderstorms are
  possible over the High Plains, mainly north of the North
  Platte River.

- Southwest winds will increase Monday, bringing the potential
  for critical fire weather conditions over the High Plains and
  a brief period of high winds in the wind prone areas.

- Elevated fire weather conditions will continue for much of
  the week ahead.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 315 PM MDT Sun Jun 28 2026

A sprawling, unseasonably strong upper level low continues to
circulate over the northern Rockies this afternoon. Southwest flow
continues aloft with dry air moving in from the desert areas.
Temperatures are a little cooler across the area compared to
yesterday, generally in the upper 70s to 80s for most. Breezy
conditions are also continuing, but again, winds are less strong
than yesterday.

This will become a bit more interesting tonight. A surface high
pressure system is moving into western Wyoming, with a boundary
currently stalled roughly from Medicine Bow Peak towards the
southwest corner of South Dakota. Meanwhile, lee cyclogenesis is
occurring over northeast Colorado. This is expected to
strengthen rapidly this evening and then begin to eject
northeastward overnight. The surface cyclone is unusually strong
for summer. NAEFS mean MSLP is approaching the climatological
minimum this afternoon and evening. As this system strengthens,
it will pull the stalled boundary to the south and east,
ushering in a surge in northwest winds across the area
overnight. Expect most of the area to remain breezy to windy
overnight as a tight pressure gradient remains in place over the
plains. Meanwhile, a secondary vort-max rotating around the
primary upper level low will dig into the Great Basin, enhancing
southerly flow aloft on top of the developing surface cyclone.
The combination of overrunning warm air advection aloft and
potent low to mid level frontogenesis will support fairly strong
forcing for ascent overnight. Expect a few showers to develop
late afternoon into the evening along this boundary, mostly
inside/north of a Douglas to Wheatland to Chadron line. Elevated
instability will increase through the evening as low level
moisture recovers. Expect showers to have a bit more thunder as
the evening goes on. Scattered thunderstorm potential will
continue all through the night, winding down around sundown.
High resolution models are not in very good agreement on the
extent of this nocturnal activity, but PoPs in the 20 to 50%
range are maintained in our northeastern areas (Niobrara,
northern panhandle) due to the potent forcing. Models often
struggle to handle nocturnal elevated convection, and the large-
scale picture suggests this potential tonight even if high
resolution models don`t all show this. In addition, look for
some shower activity moving into Carbon County overnight
associated with this system. Temperatures will be cool enough
that we can expect some snow mixing in about 9000 ft in
elevation or so. Those camping at high elevation tonight can
expect a chilly night with near freezing lows and perhaps a
dusting of snow by morning.

The aforementioned vort-max will swing through the area around
midday Monday. Expect a brief surge in low level height gradients
and 700-mb winds ahead of the boundary. Models have come into better
agreement on the wind forecast. Both the GFS and NAM have 700-mb
Craig to Casper height gradients peaking around 50 to 55 meters
between 15z and 18z Monday, which is supportive of marginally high
winds. Cross barrier MSLP gradients look good for high winds, but
the window is very short as this gradient is mainly associated with
a progressive frontal boundary following the vort-max aloft. So,
overall, expect winds to turn back to southwest and then rapidly
increase Monday morning, peak around noon, turn slightly more
westerly behind the frontal boundary early afternoon, and then
weaken through the remainder of the afternoon. This is pretty
much a toss-up for high winds, with in-house guidance showing
probabilities for high winds at 50% for Arlington and Bordeaux,
and 40% for the I- 80 summit. Probabilities around 30 to 40%
also extend to other areas adjacent to the typical wind prone
areas in Carbon, Converse, and Platte counties. While confidence
is fairly low, it is high enough at this time to at least
warrant a High Wind Watch for the wind prone areas. A brief
period with gusts of 60+mph may be possible in the adjacent
areas, but due to the short window and lower probabilities,
decided to hold off on including any of those areas in the
watch.

While hitting 60+mph is more uncertain, we do have high confidence
in a widespread breezy to windy day. Expect fairly widespread gusts
in the 40 to 50 mph range across the area. While temperatures will
be cooler, a very dry airmass will continue to filter into the area,
pushing RH to near critical values. South of the North Platte River,
RH should be easily critical, but winds will be a little lighter
here. Confidence in reaching critical RH values north of the North
Platte River is lower, but due to the strong expectation for winds,
the entire area was included in the Fire Weather Watch. Control
issues are likely with these winds, even if RH doesn`t quite reach
criteria. Monday will bring little to no chance for thunderstorm
activity due to the very dry airmass overspreading the area.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 315 PM MDT Sun Jun 28 2026

Tuesday, The upper level low will be lifting off to
the east back into the Northern Plains and Canadian providences as a
strong ridge over the Midwest and Eastern Seaboard begin to build.
By the late evening on Tuesday another weak shortwave will push
through the Intermountain West following the parent low moving into
Manitoba. There will be a few lobes of vorticity to play with as
this wave moves through but it looks as though all the forcing and
shower potential may lie only in the Panhandle area. As we progress
past Tuesday we become stuck in Southwest flow on the front side of
this ridge. The warm, dry, but smokey air from the Desert southwest
and the Colorado/Utah fires will be filtering over the area for the
remainder of the week. This will limit our rain chances as this dry
air removes all the moisture from the surface and lower dewpoints
and RH values. The models have a few shortwaves pushing into the
region past Tuesday but with no moisture and very limited forcing
there isn`t much confidence these waves will do anything beside
increase our gradient and produce the normal amount of wind through
our area. Fire weather will be the biggest concern as our fuels will
enter a curing state once again despite our stormy 7 days last week.
Winds will be light to marginal so it may be difficult to reach Red
Flag criteria for most of our area despite the low RH and curing
fuels. There is a trough that is suppose to move through 4th of July
weekend that the models are trying to figure out so we may get some
rain but the Intermountain West would need a pretty big trough to
dig through the four corners region for anything substantial to
reach the ground. So we shall see how the models trend but the 4th
may just be as dry as the rest of the week as well.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 525 PM MDT Sun Jun 28 2026

VFR conditions will prevail across all terminals for the duration of
this TAF period. Two things of aviation concern, showers and
thunderstorms will increase in coverage this afternoon/evening and
KCDR has the best chances of seeing something. Therefore, a PROB30
group remains for TS activity. The other concern in this forecast
period will be the drastic uptick in winds through Monday morning
where gusts will range between 30 and 45 knots, strongest at KRWL,
KLAR, and KCDR.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Fire Weather Watch from Monday morning through Monday evening
     for WYZ417>419-430>433.
     High Wind Watch from Monday morning through Monday afternoon
     for WYZ106-110-116.
NE...Fire Weather Watch from Monday morning through Monday evening
     for NEZ434>437.

&&

$$

SHORT TERM...MN
LONG TERM...MM
AVIATION...RZ