922
FXUS63 KLBF 291943
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
243 PM CDT Fri Aug 29 2025

.KEY MESSAGES...

- A Slight Risk (level 2 of 5) for severe weather is in place
  for west central Nebraska Friday evening. Large hail and
  heavy rain are the main concerns.

- Cool and rainy conditions continue through Sunday with locally heavy
  rainfall possible, mainly for areas east of Highway 183,
  where rain totals may exceed 2" in spots.

- After a brief warmup back to more seasonable values by
  Tuesday, another cool front will sweep through bringing a
  resurgence of more fall-like weather.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 242 PM CDT Fri Aug 29 2025

Satellite and radar analysis shows fairly expansive low clouds
across the area. The fairly broad coverage of BKN/OVC skies was
driven by sustained southerly flow on the backside of broad high
pressure over the Great Lakes. This was helping usher in a plume of
richer moisture within the profile which is characterized by
observed 1.30"+ precipitable water values from the 29/18z LBF RAOB.
This exceeds the 90% moving average for 08/29 and increases concern
for heavy rain over the next 24-36 hours, which will be covered
below.

For this afternoon/evening...isolated showers and general
thunderstorms were percolating across the Sandhills as of 19z (2pm
CDT). This activity was being driven by modest WAA across the area.
Though MUCAPE values were being analyzed around 1000 j/kg, activity
was remaining well severe limits for now given lack of sustained
strong lift. Eventually, as clouds continue to break up, increased
insolation should allow for slight upticks in instability. Forcing
will increase as a shortwave tracks across the central Rockies.
Coincident with peak heating and MLCAPE values climbing to around
1500 j/kg, more sustained and stronger convection should begin to
develop by 22z (5pm CDT). With the approaching shortwave and an
associated belt of enhanced mid-level flow, deep-layer shear will
also become more supportive of organized convection. The Storm
Prediction Center, with the 1630z (11:30am CDT) update, elected to
introduce a Slight Risk (level 2 of 5) for severe weather centered
on the local area. With moderate instability and 30-40 knots of 0-
6km BWD, isolated to widely scattered severe thunderstorms appear
probable. Recent CAM guidance continues to advertise at least semi-
discrete convection diving south-southeast through the afternoon.
Given expected storm mode of supercells, believe severe hail will be
the main threat though the ceiling for hail size appears to remain
limited largely due to the abundance of mid-level moisture tempering
lapse rates. Still, can`t rule out hail up to ping pong ball (1.50"
diameter) in the strongest storms. Believe damaging wind potential
remains fairly limited given lack of a deeply mixed boundary layer
and lack of greater theta-e differences in the vertical. As a subtle
LLJ develops tonight, hodographs will elongate and SRH will increase
as a result. Because of this, can`t completely rule out a tornado or
two but this will likely favor any discrete storms that remain
beyond 6-7pm. With forecast storm motions of < 20 knots within an
anomalously moist environment, believe heavy rain will be possible
in any thunderstorm. Similarly, the strongest storms will likely
produce 1-2"/hour rain rates which increases concern for flooding.
HREF Probability Matched Mean (PMM) QPF highlights fairly expansive
1"+ QPF with localized areas even surpassing 2". Believe heavy rain
leading to localized flooding will be possible. Severe convection
should quickly exit to the south by mid/late evening though
lingering general thunderstorms should persist through the overnight.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 242 PM CDT Fri Aug 29 2025

Saturday...a northern stream shortwave will dive southeast out of
the northern Plains. Subsequent height falls will lead to more
expansive rain and thunderstorms as weak low pressure crosses the
region. The combined rain and thunderstorm coverage combined with
general easterly flow will keep temperatures on the cool side.
Forecast highs will range from the upper 60s to upper 70s, or 5 to
15 degrees below normal for late August. The cooler temperatures and
anemic lapse rates aloft will also preclude any severe threat due to
little to no instability. Rain appears to be heavy for portions of
the area again, generally favoring east of Highway 183. PoPs here
climb to around 70-80% during the afternoon as a h5 low takes shape
and convergence aloft is maximized. Factoring in this potential, for
some of the same areas that are expected to see localized heavy rain
Friday night, increases concern for potential flooding. HREF PMM for
the entire period ending 12z Sunday shows widespread 1.5"+ QPF with
pockets of 4-5" total for the 48-hour time frame. For now, no Flood
Headlines are in effect but consideration will be necessary with
subsequent forecasts.

Sunday and beyond...the main disturbance aloft will be slow to
depart on Sunday but will do so in a slow manner. PoPs will decrease
from west to east as a result through late Sunday into early Monday.
Temperatures Sunday will remain cool, similar to Saturday, but
should begin to moderate slightly by the work week. Highs return to
upper 70s to lower 80s by Tuesday with mostly dry conditions
expected. That quickly ends as the next embedded mid-level
disturbance dives south out of central Canada. ECWMF Extreme
Forecast Index, while highlighting much of the upcoming week with
negative anomalies for daytime highs, emphasizes Thursday with
values reaching minus 0.7-0.9 and non-zero Shift of Tails values.
The going forecast calls for upper 60s to middle 70s east to west
but ensemble guidance, particularly the EPS, suggests even cooler
values with morning lows in the 40s. The rebound is quick, however,
with highs likely returning to 70s and low 80s by the following
weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1240 PM CDT Fri Aug 29 2025

Low stratus should persist through much of the upcoming
forecast. Attention quickly turns to the threat for
thunderstorms, some of which could be strong to severe, late
this afternoon and evening. Initially, storms will percolate in
and around VTN so have covered with a VCTS mention out of the
gate. More organized convection should develop by late afternoon
and shift southeast by early evening. This will likely bring
impacts to LBF with heavy rain potentially bringing IFR
visby/CIGs. Duration is somewhat low confidence so will cover
with a TEMPO group.

Behind storms, low stratus potential will return though to what
magnitude of impacts remains uncertain. Will carry IFR and LIFR
at LBF and VTN respectively through daybreak Saturday with
gradually increasing CIGs through the end of the period.

&&

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

&&

$$

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