345
FXUS63 KLBF 041154
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
654 AM CDT Fri Jul 4 2025

.KEY MESSAGES...

- A Marginal Risk (level 1 of 5) for severe thunderstorms is in place
  today as scattered to widespread rain and thunderstorms
  appears likely to impact Independence Day celebrations.

- Additional severe thunderstorms are possible Saturday, particularly
  west of Highway 83 in the evening.

- Fairly seasonable temperatures are expected through the
  extended forecast with recurring rain and thunderstorm
  potential (30-40%) each day.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 401 AM CDT Fri Jul 4 2025

This morning, gusty southerly flow persisted across much of the
region. This was helping hold temperatures in the low to middle 70s.
Broad high pressure to the east and lee troughing to the west was
helping promote the stronger winds and expectation is for these
winds to linger through the daytime today. Thunderstorms were
forming on the higher terrain to the west with activity struggling
to extend east. This was forming within an area of weak h7
convergence and following the mean flow aloft which was largely
south to north. This should keep most if not everything to the west
of the forecast area over through daybreak.

For Independence Day...a fairly active day is expected and impacts
to celebrations can be expected for most locations in western and
central Nebraska with one to possibly two waves of storms forecast.
A surface trough will shift east into our western zones later today
as modest low pressure forms across the Dakotas. Southerly flow
ahead of this will usher in rich atmospheric moisture. Thursday
evening RAOB data from the central and southern Plains shows most
locations exceeding 150% of normal precipitable water and continued
southerly fetch will advect these anomalous values into western
Nebraska through the day. Storm initiation should be relatively
early, likely by midday in the west, thanks to an early arriving
shortwave trough. As this feature interacts with the surface trough
and the rich moisture across the area, expecting expansive
development. The environment during the daytime will be supportive
of a few strong to severe thunderstorms: MLCAPE of 1000-2000 j/kg
and 0-6km BWD of 20-30 knots. Primary concern will be damaging wind
gusts and heavy rain. SPC maintains a Marginal Risk (level 1 of 5)
and generally have no qualms with that. Should storms manage to
remain discrete, large hail could perhaps be more of a threat but
fairly strong forcing should allow for quick upscale growth. HREF
output generally aligns well with forecaster thinking which shows
late morning rain and thunderstorms west of Highway 83 but more
robust activity then developing by early afternoon and translating
west to east. Storms will progress west to east at roughly 15 to 20
mph and this should carry the first round out of the area by mid-
evening. Regarding heavy rain potential...as mentioned, anomalous
moisture will be in place across the region. Forecast soundings show
fairly evenly distributed instability throughout the profile with
the lack of more robust instability. With deep warm cloud layers,
skinny CAPE profiles, and relatively slow storm motions, expecting
heavy rain to be a threat for many. Limiting overall concern will be
the lack of training storms. Various CAM guidance shows pockets of 1-
2" per hour rain rates, notably the HRRR/ARW/FV3 outputs, and this
correlates to HREF neighborhood probabilities > 1"/hour rain rates
approaching 50%. Following heavy rainfall last week, Flash Flood
Guidance values remain fairly modest with many locations south of
Highway 92 seeing values around 1-1.5". Given fairly localized cores
of heavier rain, will forgo any headline issuance but am concerned
about some flood potential. Expansive rain and thunderstorms this
afternoon will also hold temperatures back across the area. Did
trend values down utilizing NBM/MAV/ECS guidance. This paints low to
middle 80s across the area. A second round of thunderstorms will be
possible later this evening focused across our western zones. This
round will largely occur within increasing convergence as a complex
tracking out of northeast Wyoming interacts with orographic features
to the west. With modest lapse rates largely intact across the area
overtop warm and moist low-levels, marginal instability will remain
in place. Forecast soundings show elevated instability, rooted
around h85, with sufficient deep-layer shear thanks to enhanced h5
flow. Believe the main threat with this activity will be damaging
wind gusts again with multicell clusters. Timing of this round
appears to favor mid to late evening so late evening holiday
festivities may be affected. Folks should plan to monitor the
weather throughout the day.

Saturday...another wave of rain and thunderstorms appears probable
across western and central Nebraska though the bulk of the daytime
should remain dry. Behind departing rain and thunderstorms early in
the morning, dry weather returns through the afternoon hours for
much of the forecast area. Behind departing surface trough,
northerly flow will become establish around midday. With the lack of
greater cloud coverage similar to Friday, expecting a warmer day
with afternoon highs climbing into the middle 80s to lower 90s.
Later in the day, winds will back to more easterly which will push
richer moisture up along the Front Range. Storms look to initiate
along I-25 to the west by late afternoon. Within general westerly
mid-level flow, storms should push off the higher terrain and enter
western Nebraska by early evening. What appears most uncertain is
the downstream environment and how supportive this will be for
sustained convection. While an increasing LLJ appears likely, focus
appears to be north into western South Dakota. This supports a
greater environment largely to our north. The 06z HRRR run appears
to showcase this well with eastern Wyoming activity struggling to
extend east beyond the Highway 385 corridor and a more mature,
notable MCS developing near and north of I-90. A closer look at
ensemble guidance supports the threat remaining north as both
EPS/GEFS QPF probabilities remain highest to the north. For now, SPC
maintains a Slight Risk (level 2 of 5) for the immediate Pine Ridge
vicinity with a broad Marginal Risk (level 1) for areas west of
Highway 83. Believe this to be adequate coverage for now.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 401 AM CDT Fri Jul 4 2025

Broad upper ridging will build across the Desert Southwest and the
Central Plains located on the northern periphery of said feature.
This should allow for a continuation of near to slightly above
normal temperatures for the extended period. Extended guidance
doesn`t suggest much in the way for anomalous weather as ECMWF
Extreme Forecast Index values remain muted for the bulk of next
week. NBM inner-quartile temperature values exhibit little wavering
as well with spreads around 4-8F day to day. This suggests a fairly
high confidence in seeing afternoon temperatures hold firm in the
middle 80s to lower 90s. For the first half of next week, general
zonal flow will be in place. High pressure to the east will promote
continued southerly flow which should support daily rain and
thunderstorm chances with activity forming then moving off the
higher terrain to the west. Precipitation probabilities will reach
about 40-50% each day Sunday through Tuesday with EPS/GEFS
probabilities of daily rain exceeding 0.10" around 40-60%. Ridging
will amplify around the middle of the week. This will coincide with
slightly warmer temperatures and decreased precipitation potential.
Even with the warmer temperatures, values should remain around +5F
compared to seasonal norms. A few weaker impulses in the
northwesterly flow will take aim on the central Plains towards the
late week but EPS/GEFS/NBM probabilities decrease for the time frame
and suggest a drier period in the forecast.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 648 AM CDT Fri Jul 4 2025

Increasing cloudiness with scattered to widespread rain and
thunderstorms will hamper aviation operations across western
Nebraska Friday.

High level clouds continue to filter in from the west as rain
and thunderstorms percolate near a SNY to AIA line. This
activity will gradually shift east through the daytime and bring
impacts to both LBF and VTN this afternoon. Believe magnitude of
impacts at LBF to be greater with heavy rain potentially leading
to low-end MVFR visibilities. Can`t completely rule out greater
impacts but will defer to later forecasts as confidence
increases. Following the departure of thunderstorms during the
day, expect a quick return to VFR conditions before a second
round of thunderstorms threatens from the west. Confidence in
this round materializing and impacting either terminal is lower.
Will include a PROB30 to cover the potential at LBF with
necessary inclusion with later forecasts.

Believe VFR conditions again return prior to the end of the
period but some NWP guidance hints at fog so will monitor trends
going forward.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...NMJ