Sidney, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

713
FXUS65 KCYS 250536
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1136 PM MDT Thu Apr 24 2025

.KEY MESSAGES...

- There is a marginal risk for thunderstorms capable of
  producing hail and strong winds, mainly along the corridor
  from roughly Laramie to Pine Bluffs.

- Adequate low and mid level moisture along with passing weather
  disturbances will help produce a few showers and
  thunderstorms nearly every day.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 305 PM MDT Thu Apr 24 2025

An early season convective threat is materializing this afternoon as
a weak shortwave trough passes north of the area. Current GOES
satellite imagery shows the thick deck of low clouds parked just
east of the Laramie Range, and continuing to cover most of the High
Plains. Today though, good moisture has pushed well into Carbon and
Albany counties with dewpoints in the mid 30s. After the fog/low
clouds broke there this morning, the atmosphere was permitted to
destabilize with the sunshine, and current mesoanalysis indicates
about 500 to 1000 J/kg surface-based CAPE covering most of the
counties. Further east, the low clouds are holding in an inversion
layer over the High Plains, but a fair amount of elevated
instability (up to about 500 J /kg) is still present above. This was
tapped by a few weak storms that developed over the northern NE
panhandle earlier today. Low-level convergence/frontogenesis and
modest isentropic lift are providing enough broad scale lift to kick
some storms off. Expect storms to increase in coverage over
Carbon/Albany counties and then spread eastward over the next few
hours, with a few rounds possible between now and about midnight.
The main threat with today`s storms will be hail. Plentiful low
level moisture and the stable layer over the High Plains will make
it difficult but not impossible to get severe winds. Most hail today
should be of the small variety (although there is potential for
quite a bit of accumulating small hail), but an isolated storm or
two may produce marginally severe hail. Initially, expect to see
storms struggle east of the Laramie range, but as we head later into
the afternoon and evening hours, gradual moistening of the cloud
layer and a subtle increase in elevated instability should allow for
showers and storms to survive further east. Showers with embedded
thunder should continue through about midnight, after which time the
vort-max will pass to the east of the area, shutting off the
isentropic lift and initiating a drying trend above about 500-mb.

Low-level upslope flow will remain potent through the overnight
hours and into Friday morning as the surface front surges south and
west and a strong high pressure system settles in over the western
Dakotas. Light shower activity should keep going over the High
Plains after midnight, and this may get a boost after daybreak as
isentropic lift kicks in again. The low level inversion will be much
stronger on Friday compared to today. Thick low cloud cover will
keep chilly temperatures in place along and east of the Laramie
range. Forecast highs were nudged to the NBM 10th percentile with
little to no sunshine expected for this area. We should see some
partial clearing from Laramie to Rawlins and points south of the
interstate which may lead to some marginal instability. Overall
though, Friday looks like a more limited light shower day with a few
isolated rumbles of thunder. The front pushing up against the range
will lead to some fairly potent reverse pressure gradients across
the I-80 wind prone areas. We may see wind gusts approaching 50 mph
around the I-80 summit towards Elk Mountain, but the direction will
be southeast in the Laramie valley, and east around the
Arlington/Elk Mountain area.

As we head into the weekend, a broad longwave trough will dig into
the West Coast and amplify the downstream ridge positioned over our
area. This will nudge the moist region of isentropic lift off to the
east Friday night and strengthen southerly flow as the surface high
retreats to the east. Expect a big jump in highs on Saturday with
most areas reaching the mid 60s to mid 70s after cloud cover
retreats from west to east through the day. Isolated thunderstorms
will be possible once again on Saturday, but coverage should be more
limited.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 350 AM MDT Thu Apr 24 2025

Sunday...As the primary trough aloft moves into Utah, southwest
flow aloft strengthens over our counties, helping to produce a
surface lee trough, which will act as a focus for isolated to
scattered late day showers and thunderstorms.

Monday...As a potent shortwave trough aloft and its associated cold
front move across our counties, we expect scattered showers and
isolated thunderstorms. Cooler 700 mb temperatures near -2 Celsius
will yield high temperatures in the 50s to mid 60s.

Tuesday...Northwest flow aloft prevails in the wake of the shortwave
trough and cold frontal passage. Looks like enough low and mid level
moisture and cyclonic flow aloft to produce scattered to numerous
showers and perhaps a few thunderstorms. Somewhat cooler
temperatures in the wake of the cold front.

Wednesday...A somewhat drier airmass moves in with northwest flow
aloft, producing a decrease in afternoon and evening shower and
thunderstorm coverage. Maximum temperatures will be about the same
as those from Tuesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1123 PM MDT Thu Apr 24 2025

Southwest flow aloft will continue with disturbances in the
flow, while moist low level upslope continues to produce low
clouds, showers and fog.

Wyoming TAFS...For Rawlins and Laramie, ceilings will range from
500 to 2000 feet until 21Z, with periods of fog at times until
16Z, reducing visibilities to 1 to 2 miles, then ceilings will
improve to 3500 to 5000 feet after 21Z. Winds will gust to
28 knots at Laramie after 16Z.

For Cheyenne, ceilings will range from 200 to 500 feet, with fog
reducing visibilities to 1/2 mile from 08Z to 15Z.

Nebraska TAFS...Ceilings will range from 300 to 1500 feet, with
areas of fog and showers reducing visibilities to 1 to 5 miles
at Chadron and Alliance until 18Z, and to 1 to 5 miles at
Scottsbluff and Sidney through the entire period.

&&

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

&&

$$

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