-- Discussion containing changed information from previous version are highlighted. --
469
FXUS63 KLBF 241911
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
211 PM CDT Mon Jun 24 2024

.KEY MESSAGES...

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- Thunderstorm chances through Thursday will be of concern.

- Drier and cooler weather is expected this weekend as high
  pressure settles in from the north.

- Heat and humidity return next week along with at least
  isolated thunderstorm chances.
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&&

.SHORT TERM /THROUGH TONIGHT/...
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Issued at 209 PM CDT Mon Jun 24 2024

Surface low pressure is located across southeast SD this afternoon.
A warm front extends southeastward from the low into IA with a
surface trough extending back to the southwest into northern and
central Nebraska. West of the surface trough the boundary layer is
well mixed and dry, while to the east dew points are much higher
with a moist boundary layer. Instability is much greater east of the
trough with SFC based CAPES running around 3000 J/KG. Bulk shear
values aren`t overly strong...generally around 25 kts or so. DCAPE
values are highest west of the surface trough across western
Nebraska. Most CAMs indicate that isolated to widely scattered
convection will move eastward off the higher terrain into western
Nebraska late this afternoon. This will be within the deeply, well
mixed boundary layer, and gusty winds will be of  concern with this
activity. An isolated severe gust could occur but widespread
damaging wind is not expected due to the isolated nature of the
activity. The elevated mixed layer is quite strong this afternoon
with H7 temps near 15C. This may tend to suppress development along
and east of the surface trough across central into eastern Nebraska.

A weak cold front settles southward into Nebraska tonight. This
front stalls with a weak surface low developing Tuesday across
southern Nebraska. Low-level surface flow becomes easterly Tuesday
across north central Nebraska to the north of this feature. Surface
dew points pool in the lower 70s in this area leading to strong
instability by afternoon. Shear will also increase due to the
easterly low-level flow. Cap is weaker Tuesday and CAMs indicate
isolated convection developing over portions of eastern north
central Nebraska (Holt county) mid to late afternoon. Shear and
instability is such that a supercell or two could quickly evolve out
of this activity. They would be right movers and turn southeastward
toward northeast Nebraska. This scenario will have to be monitored
closely Tuesday.

Wednesday could bring more convection to the area. The region will
be strongly sheared as low-level southeasterly upslope flow
increases. Appears convection will most likely initiate within a
favorable, moist upslope environment across southwest SD and eastern
WY. This activity could then grow upscale into western Nebraska
aided by an increasing southeast low-level jet Wednesday
evening.
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&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
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Issued at 209 PM CDT Mon Jun 24 2024

Upper level low pressure drops into the Pacific northwest Thursday
then crosses through southern Canada Friday into Saturday. After
another potentially active convective day Thursday, it appears that
Friday through Sunday will be more quiet. As the trough/upper low
pass to our north, expect surface high pressure to build southward
through the Dakotas and into Nebraska by Saturday. Sunday night and
beyond could become active again as the surface high moves east and
moist return southerly low-level flow develops once again. At this
point though it appears any convection next week will remain
isolated to scattered...with no signal for any heavy or organized
areas of rainfall noted. Temperatures this week fall below normal as
the high pressure settles in from the north. Heat and humidity
return next week with the return southerly low-level flow.
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&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 1205 AM CDT Mon Jun 24 2024

Little more than some mid clouds over central and western
Nebraska early this afternoon, but there may be some isolated
thunderstorm development late in the day and into this evening.
Coverage is expected to be sparse so not enough confidence to
warrant a TEMPO or even a VCTS. Will monitor radar trends
closely and amend if activity develops on a trajectory to impact
a TAF site. Any convection will wane quickly with loss of
diurnal heating toward sunset so expect dry conditions
overnight and through the end of the valid period. There is a
hint for some sub-VFR CIGs to move down from the north and
affect KVTN late Tuesday morning but probabilistic guidance
shows a 30 percent chance or less for CIGs at or below 3kft AGL,
so will put in some low VFR SCT clouds and see if a trend for
lower CIGs develops as later guidance becomes available.

The boundary layer is hot, dry, and deeply mixed. This will
create some gusty conditions into early this evening before
winds diminish for the overnight period. Note however that in
this environment any storms that do develop will be capable of
producing strong and erratic gusty outflow winds that may
travel a good distance from the parent convection. Lack of
confidence in timing and location of convection prohibits a
specific mention in the TAF but pilots should anticipate rapid
changes in wind speed and direction near any thunderstorms.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT /7 PM MDT/ this evening for
NEZ007-010-027>029-038-059-069>071.

&&

$$

SHORT TERM...Taylor
LONG TERM...Taylor
AVIATION...MBS