Area Forecast Discussion
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FXUS64 KLUB 212328
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
628 PM CDT Thu Mar 21 2024

...New AVIATION...

.SHORT TERM...
(This evening through Friday)
Issued at 218 PM CDT Thu Mar 21 2024

A low-amplitude, shortwave trough continues to pivot eastward over
West Texas this afternoon with a well-defined, vertically-stacked
low rotating over east-central New Mexico. To the south of the CWA,
a 500 mb jet streak near 50 kt was emerging over the Big Bend with
its exit-region arcing over the eastern Rolling Plains. Mid-level
cloud debris persists along the northern periphery of the jet streak
rounding the base of the shortwave trough, with the field of moist,
isentropic ascent aided by the proximity of the upstream vorticity
lobe. A wavy surface pattern is present across the CWA with the
center of a cyclone now rotating into the Big Country as its
movement is anchored to a quasi-stationary front draped along the
Upper Red River Valley. A north-south-oriented surface trough was
also analyzed across the western South Plains, with its movement
reinforced by the presence of a secondary surface low congruent with
the position of the vorticity lobe. Billows were also detected
beneath the dissipating cirrus debris, which are steadily eroding as
insolation increases and destabilization of the airmass occurs. This
has resulted in the development of two surface-based cu fields
across portions of the South Plains and in the southeastern Rolling
Plains on the south side of the quasi-stationary front where weak
RADAR echoes are already present. Diabatic heating and the
dissipation of the low stratus field will continue to be delayed
within the rain-cooled airmass delineated across most of the Rolling
Plains per recent WTM data, with the differential heating boundaries
serving as a foci for the initiation of isolated-to-scattered showers
and thunderstorms this afternoon across portions of the Caprock.

Recent trends in visible satellite imagery show that the cu field
near PVW is quite shallow, and it appears that the best potential
for the initiation of additional showers/thunderstorms will be along
the eastward-propagating surface trough across the western South
Plains over the next few hours. While the cu field across the
aforementioned area is surface-based, webcam views from the office
indicate that it is also high-based; and the primary storm mode this
afternoon will be single-cells to a few multi-cellular clusters. Due
to the position of the shortwave trough, effective shear magnitudes
are substantially weak; however, small hail (dime size or smaller)
and a strong, rogue wind gust cannot be ruled out with the expected
pulsing-type convection this afternoon. The severe weather threat is
very low. Chances for convection will wane quickly tonight as
nocturnal stabilization of the boundary-layer occurs in addition to
the base of the shortwave trough pivoting over central North Texas.
As NVA advects in on the backside of the departing system, cloud
debris will clear; and the combination of a clear sky and light
winds will allow the boundary-layer to reach saturation with the
development of fog forecast to occur across most of the Rolling
Plains. Some of the fog could become dense. Further west, patchy fog
will be possible; however, confidence is too low to include fog in
the official forecast. Any fog that develops will dissipate by the
late morning hours Friday, with a weakening cold front set to move
through the CWA tomorrow as well. A line of high-based cu may
develop along the cold front, but showers and thunderstorms are not
expected to develop as dry air entrainment and confluent flow aloft
keep the cu field shallow. The passage of the front will have little
affect on temperatures, with highs peaking in the lower-middle 70s.

Sincavage

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 218 PM CDT Thu Mar 21 2024

Confidence is improving in regards to a potential high wind event on
Sunday over parts of the region followed by a conditional threat for
severe storms later that evening, mainly in the Rolling Plains. But
before we get to this impactful day, a few changes to the pattern
will already be underway Friday night through Saturday. A northern
stream trough over the Dakotas on Friday will have shoved a weak
cold front our way which should be clearing the region around sunset
ahead of cool NE winds. These winds will quickly veer east overnight
and later southerly on Saturday as lee troughing sharpens to our
west. This sequence is in response to robust height and pressure
falls focusing in CO and NM well ahead of a vigorous trough peeling
across the Great Basin. Despite this, already stiff southerly winds
of 20-30 mph on Saturday won`t hold a candle to Sunday as the
leading edge of the trough ejects across the TX & OK Panhandles.
Strong cyclogenesis in eastern CO along with deep mixing into wind
maxima of 50-65 knots from 800-600 mb could easily garner a high
wind event over much of the Caprock. Given the last two runs of the
ECMWF are trending faster with this trough and ensemble spread
overall is decreasing, it looks more probable that winds will fare
higher which would also shove the dryline well into the Rolling
Plains (and perhaps beyond) by Sunday afternoon. Opted to keep NBM`s
20-30 PoPs across our eastern zones Sunday evening as the dryline
may stall close enough or even retreat a bit before a Pacific cold
front speeds east after sunset, although this window for precip is
looking even smaller now given such stout post-dryline winds.
Another cold front arrives on Monday with much cooler northerly
winds under the base of a broad trough. Even though high temps drop
to below normal, much colder temps aloft and lingering moisture will
make for favorable lapse rates supportive of light showers including
some snow mixing in for a few locales Monday morning. Drier and
milder conditions return Tuesday and Wednesday under deamplifying
westerly flow.

&&

.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Thu Mar 21 2024

Last thunderstorms associated with the upper low moving across the
southern High Plains are now east of KLBB and KPVW and should not
affect those two terminals any more. TS will approach KCDS in the
first few hours of the TAF period, but with sunset approaching
these storms are expected to diminish before reaching that
terminal. Focus then shifts to potential for IFR ceilings and fog
early morning hours Friday. Best chance of that happening is at
KCDS where low level moisture is the richest and have run with a
prevailing group there a few hours either side of 12Z. Some hi-res
models are now suggesting KLBB and KPVW could also see stratus and
fog, although some robust moistening will need to occur. This is
definitely not out of the question, although confidence is not
quite high enough to insert a mention in those TAFs at this time.
Finally, with a nationwide METAR outage ongoing there are no plans
to amend the current set of TAFs.

&&

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

$$

SHORT TERM...09
LONG TERM....93
AVIATION...07


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