504
FXUS63 KLBF 011115
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
615 AM CDT Sat Jun 1 2024

.KEY MESSAGES...

-  Storms are anticipated to move into the area late this
   afternoon and evening, with a threat for very large hail and
   damaging winds.

- Confidence is increasing in a line of severe thunderstorms
  capable of producing significant (>75mph) wind gusts Sunday
  evening across the area.

-  Additional threats for thunderstorms exist Monday and
   Tuesday, though the threat for any severe weather remains
   unclear.

-  A lull in precipitation is expected into mid-week, with
   showers/thunderstorms then returning late week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 409 AM CDT Sat Jun 1 2024

Currently, elevated supercells have developed across the Panhandle,
in a broad warm advection regime atop a largely stable boundary
layer. Shear profiles remain supportive of these supercells
sustaining through at least sunrise, with right mover motions off to
the southeast. Extrapolation suggests a continued threat for large
hail for areas near and west of HWY 83 and along and south of HWY 2,
where the best overlap of elevated instability and deep layer shear
exists. As low level flow weakens after sunrise, convection should
eventually weaken and dry conditions should then persist into this
afternoon.

By late afternoon, persistent southeasterly flow will promote
dewpoints increasing into the upper 50s to low 60s across southwest
Nebraska. With steepening lapse rates aloft, MLCAPE values look to
climb to >2000 J/kg south of HWY 2, with lessening values to the
north. High-res guidance continues to point to initial discrete
thunderstorm development across northeast Colorado by late
afternoon, as inhibition erodes and convergence increases along
a dryline. Additional scattered thunderstorm development is
possible further northeast into western/central Nebraska along
any more diffuse surface boundaries, though confidence in this
remains low for now. For any storms that form, deep layer shear
vectors look to be more than supportive of supercells, with at
least some clockwise curvature in the lowest few kilometers
initially and increasing hodograph length with height. With
time into the late evening, the low level jet will begin to
strengthen from the south and lead to increasing low level
curvature/shear across much of the area. There does appear to be
a brief window should any thunderstorms remain discrete in the
late evening hours. The more prevalent threat looks to be large
to very large hail, with adequate deep layer shear, steep mid-
level lapse rates, good CAPE distributions (largely
subfreezing),and mid-level storm relative wind vectors largely
perpendicular to the initiating dryline. Some damaging wind
threat will accompany storms as well. It appears the threat
should be maximized in the evening and early overnight hours,
before waning due to a combination of both a stabilizing
boundary layer and storms exiting the area to the east.

The next, potentially high impact, round of severe thunderstorms
looks to be on tap for Sunday afternoon and evening across much of
western and north central Nebraska. A similar environment looks
to be in place across the area in the afternoon on Sunday, with
upper 50 to low 60 dewpoints overspreading the area. Ample
MLCAPE again will be present, with adequate deep layer shear to
support updraft organization. As a shortwave trough crosses the
Rockies Sunday evening, an associated surface low will eject
northeastward across the Dakotas, dragging a cold front through
the area during the afternoon. Increased convergence along this
encroaching cold front should allow for rapid thunderstorm
formation, and enough forcing should exist for at least a broken
line of storms. The environment across the warm sector
continues to look rather concerning with respect to damaging
wind potential, with good inverted-v sounding profiles, high
LCLs above the dry sub-cloud layer, and robust DCAPE values. In
fact, the majority of this evening`s high-res guidance suite
paints the potential for 80-85mph wind gusts embedded in the
quick moving squall line Sunday evening. More than agree with
the inclusion of a significant wind threat in the current Day 2
SPC outlook, and confidence continues to grow in the potential
for localized high impact damaging winds Sunday evening.
Precisely where this occurs is somewhat low confidence, though
nearly all high-res guidance members point to this somewhere
across western and north central Nebraska. The bottom line, a
significant damaging wind event is possible across portions of
the area Sunday afternoon and evening, and later forecasts
should be monitored closely (especially for those with outdoor
plans!).

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 409 AM CDT Sat Jun 1 2024

Additional thunderstorm threats will persist into Monday and
Tuesday, though confidence wanes with respect to frontal boundary
positioning and associated corridors of best thunderstorm potential.
Drier conditions are then expected into midweek, as heights rise
aloft and upper ridging begins to establish across the western
CONUS. Discrepancies remain between deterministic and ensemble
solutions on the orientation and positioning of both the western
CONUS ridge and and eastern US trough, leading to lowered confidence
for late week and beyond. That said, the background northwesterly
flow aloft would point to at least some returning threat for strong
to severe thunderstorms, and this will need to be monitored going
forward.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 615 AM CDT Sat Jun 1 2024

A few aviation weather concerns exist through the forecast
period, including thunderstorms, low ceilings, and potentially
fog. The first wave of moisture continues during the early to
mid morning with bouts of heavy rain and possibly hail. IFR
ceilings and visby are also possible for the southern terminals
(LBF) around sunrise due to fog. Another round of storms will
likely develop in the panhandle late afternoon and approach LBF
toward sunset. Meanwhile, generally light east surface winds
will strengthen during the day and transition to
south/southeast.

&&

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

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...Snively