096
FXUS64 KLUB 102331
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
631 PM CDT Fri May 10 2024

...New AVIATION...

.SHORT TERM...
(This evening through Saturday)
Issued at 236 PM CDT Fri May 10 2024

Surface ridging anchored from eastern CO through northern OK was
maintaining cool E-NE winds across the region this afternoon. Aloft,
a ridge axis around 700 mb was bisecting the CWA from N-S and is
scheduled to drift east tonight ahead of a shortwave trough in SW
flow. Well to our southeast and beyond the influence of this ridge
across the Big Country to the Hill Country, radar and satellite
showed a smattering of elevated thunderstorms at 2 PM which have
been poorly handled by most models. Fortunately, this activity will
not pose a threat to our area.

After a gradual downturn in clouds later this evening owing to
subsidence well ahead of the aforementioned upper impulse, moist
isentropic ascent will amplify after midnight resulting in PWATs
rising to around 1 inch which is nearly double that of normal. This
moistening theme will carry through the day on Saturday with likely
PoPs favoring all but our far southeast TX Panhandle counties and
the northern Rolling Plains where deeper drying in the low levels
looks to take its toll on measurable rain. The NAM seems too eager
to overturn this dry layer through the day, so will favor a blend of
the HREF mean and NBM which keeps the heaviest rainfall of 1/3" to
1/2" across the southern half of the forecast area. Elevated CAPE
remains generally low but still sufficient for some thunder at
times. High temps are still tricky as some of the coolest guidance
from yesterday`s models have since eased somewhat which raises
confidence in the slightly "milder" NBM values.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 236 PM CDT Fri May 10 2024

An opening, positively-tilted trough is forecast to emerge over the
western Great Plains on Saturday night as an elongated 250 mb jet
streak continues to translate over the CWA within the split-flow
regime encompassing the Lower 48. Geopotential height falls will be
dampened by the deamplification of the trough as it ejects over the
south-central Great Plains heading into Sunday morning, which will
temper the magnitude of mid-level cooling while west-southwesterly
flow aloft maintains the advection of an anemic, elevated CAPE
profile with most-unstable parcel trajectories yielding <=1,000 J/kg
of MUCAPE amidst moist-adiabatic lapse rates. WAA-induced showers
and thunderstorms will, therefore, be ongoing at the start of the
period; however, the overall QPF footprint should be light with only
a few locales experience brief downpours/thunderstorms on Sunday
morning. At the surface, weak cyclogenesis will occur near the
vicinity of the OK PH/northern TX PH beneath the opening circulation
in the mid-levels while a quasi-stationary front should be anchored
along the edge of the Mescalero Escarpment.

The position of the stalled front beneath the base of the shortwave
trough, and presence of the thermally indirect circulation aloft,
will result in renewed frontogenesis with the quasi-stationary front
transitioning into a cold front and moving eastward onto the Caprock
during the afternoon hours on Sunday. Elongation of hodographs aloft
with LFCs rooted above a deep, moistened boundary-layer, will
facilitate an increase in the coverage of showers and thunderstorms
across portions of the Caprock and into the Rolling Plains as moist,
isentropic ascent continues to overspread the CWA. Marginally-severe
hail (near quarter size) should accompany the best-organized cells
as the magnitude of the deep- and cloud-layer shear vectors support
weak, mid-level rotation; and as wet-bulb zero heights lower to near
8.0 kft AGL from the weak, geopotential height falls. Locally heavy
rainfall will accompany the stronger cells, although the potential
for flash flooding is low due to the expectation of storm motion
being governed via advection versus propagation. (Mean wind storm
motion vectors are forecast to be near 40-45 kt.)

The base of the positively-tilted trough will pass east of the CWA
by Sunday night, with thunderstorm chances ending from west-to-east
accordingly. A weakening cold front will move southward across the
entire CWA following the passage of the trough; however, despite the
presence of northwesterly flow at the surface through mid-levels,
the boundary-layer should become well-mixed on Monday afternoon with
little in the way of CAA post-FROPA as temperatures warm into the
upper 70s and lower 80s area-wide. A low-amplitude, shortwave ridge
is then forecast to shift over the CWA on Tuesday ahead of another
amplifying trough to the west. Global NWP guidance is in agreement
with the split-flow pattern beginning to phase by mid-week as the
broad, positively-tilted trough ejects over the southern Rocky
Mountains. This will facilitate the evolution of cross-boundary
shear vectors across West Texas by the middle of the week amidst the
presence of return flow and a dryline positioned in the vicinity of
the CWA. The potential for severe thunderstorms is set to return
during this D6/D7 window.

Sincavage

&&

.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Fri May 10 2024

VFR and modest east winds will continue at all sites this evening
through the overnight hours. Scattered to numerous SHRA will then
develop south of LBB during the early/mid morning hours on
Saturday, then will spread northward impacting both LBB and PVW
and potentially CDS as well from late morning through most of the
rest of the day. A few embedded TS are also possible, but
coverage is expected to be limited and will omit thunder mention
from TAFs for this issuance. CIGs are currently expected to
remain VFR at all sites through this TAF period, with better
potential for MVFR/IFR CIGs not arriving until after 00z on
Sunday.

&&

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

$$

SHORT TERM...93
LONG TERM....09
AVIATION...30