873
FXUS64 KLUB 091111
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
611 AM CDT Tue Jul 9 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 246 AM CDT Tue Jul 9 2024

06Z upper air analysis reveals a positively-tilted shortwave trough
ejecting over the Mississippi River Valley, with its base beginning
to approach central North Texas as per recent water-vapor imagery.
Farther west, a subtropical ridge was centered over the Mojave and
Sonoran Deserts, where a 250 mb jet streak that was objectively
analyzed on the 09/00Z upper air map data has weakened to 40 kt and
is accompanied by an ill-defined vorticity lobe rotating over the
Cricket Mountains. Increasing NVA/subsidence on the backside of the
mid/upper-level trough continues to advect into the region which has
resulted in excellent boundary-layer cooling this early morning; and
patchy, small areas of mid-level stratus continue to linger across
portions of the extreme southern TX PH and South Plains with an
otherwise crystal clear sky.

At the surface, a quasi-stationary front is located far to the south
of the CWA and bends northeastward across the Edwards Plateau before
extending northward to the east of the 100th meridian. West Texas
Mesonet (WTM) data analyzes an anticyclone centered to the northeast
of LBB, and between Floydada and Ralls; and winds were calm across
the entire CWA. Leaf wetness on the WTM data was near zero except
for a few locales despite relative humidity moistening to above 80
percent, and unless there is a spike in leaf wetness measurements,
patchy fog appears to be a very low probability through sunrise.
Trends will continue to be monitored. The benign surface pattern
will remain intact throughout the scope of the short-term period,
with winds remaining calm today as the anticyclone slowly rotates
eastward into the Red River Valley.

The mid/upper-level trough will be slow to pivot eastward throughout
the day today as a subtropical ridge amplifies across the eastern
Atlantic Basin, with its base forecast to still be present over
central North Texas by 10/00Z this evening; however, the 250 mb jet
streak embedded within the trough will continue to translate
northeastward as it interacts with and absorbs Tropical Depression
Beryl. Northwesterly flow will persist over the region today with
boundary-layer heights capped near 700 mb beneath warm mid-levels
and a slim, residual, elevated mixed layer (EML). Full insolation
will result in a well-mixed boundary-layer developing beneath the
cap, with Inverted-V profiles evolving as temperatures rise into the
upper 80s and lower 90s area-wide from the gradual increase in
geopotential heights as the subtropical ridge over the Mojave and
Sonoran Deserts expands eastward.

Scattered thunderstorms are forecast to develop far northwest of the
CWA this afternoon as the 250 mb jet streak noses over the Sangre de
Cristo Mountains and into the western High Plains. The expectation
is for this complex to advect southeastward along the mean wind
vector and arrive near the TX/NM state line towards 10/00Z. However,
boundary-layer decoupling, in addition to the eroded EML, should
result in the complex of storms to begin weakening with coverage
becoming more-widely-scattered to perhaps even isolated as it
crosses into the CWA. Convection will become elevated after sunset,
which will eliminate the potential for gusts; and updrafts should
begin to struggle to produce lightning after 10/05Z (midnight CDT)
with showers lingering across the far western South Plains by that
time. The highest PoPs, which were capped at 30 percent, remain
along and west of the HWY-385 corridor as the decaying complex is
forecast to move southward after dark. Warmer temperatures will
follow heading into Wednesday morning as anvil debris minimizes the
loss of longwave radiation amidst light and variable winds.

Sincavage

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 246 AM CDT Tue Jul 9 2024

The subtropical ridge over the western U.S. will continue to wobble
eastward on Wednesday as its position is modulated by a shortwave
trough digging into the Alexander Archipelago. Meanwhile, the
positively-tilted trough will become more-basal as its associated
jet streaks translate over the Ohio River Valley, with a corridor of
largely difluent, mid-level flow advecting into the CWA throughout
the day. Several smaller-scale perturbations and ill-defined
vorticity lobes will arc over the apex of the ridge and propagate
southeastward within the eastern tranche of the expanding ridge from
the west, and with a more-northerly component to the mid-level flow,
the EML should improve in size and depth compared to Tuesday as
forecast soundings indicate mixed-layer parcels yielding nearly
1,500 J/kg of CAPE. The boundary-layer will become well-mixed once
again as slightly hotter temperatures are expected as surface flow
veers to the southwest, further eroding the minimal MLCINH in place
during the early afternoon hours.

Scattered, multi-cellular clusters are forecast to develop across
the Caprock and into portions of the Rolling Plains on Wednesday
afternoon and into the evening; and storm motions will be governed
by propagation from cold pools versus advection with the mean wind
aloft. Inverted-V boundary-layer profiles beneath water-loaded
updrafts will yield the possibility for isolated wind gusts in
excess of 60 mph to occur with the organized clusters. Localized
flooding will be possible due to the slow movement of storms. The
spatiotemporal coverage of storms will begin to wane after dark as
nocturnal stabilization of the boundary-layer occurs.

By Thursday, mid/upper-level flow will dampen substantially as the
waveguide of the basal troughing continues to attenuate from the
amplifying ridges over the western U.S. and eastern Atlantic Basin.
Diffuse surface troughing may serve as a focus for convective
development across portions of the South Plains on Thursday
afternoon, with pulse-like, single- and multi-cellular storms
possible as the mean wind vector is nearly zero given the position
of the latter synoptic-scale features. The blended PoPs were
maintained for portions of the South Plains on Thursday the
barotropic airmass maintains a similar thermodynamic profile at the
surface and aloft compared to the prior days. Doldrum-like
conditions will follow heading into Friday and next weekend as
little change occurs with the airmass as the subtropical ridges over
the western U.S. and eastern Atlantic Basin begin to phase.

Sincavage

&&

.AVIATION...
(12Z TAFS)
Issued at 611 AM CDT Tue Jul 9 2024

VFR prevails for the TAF period. A complex of thunderstorms is
forecast to near and/or cross east of the New Mexico state line
this evening, but storms are forecast to decay before reaching
KLBB and KPVW. Smooth air can be found near 10-12 kft MSL this
afternoon across West Texas. Check density altitude.

Sincavage

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...09
LONG TERM....09
AVIATION...09