595
FXUS64 KLUB 250919 CCA
AFDLUB

Area Forecast Discussion...CORRECTED
National Weather Service Lubbock TX
319 AM CST Mon Nov 25 2024

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 319 AM CST Mon Nov 25 2024

 - Breezy post-frontal north winds today with below normal
   temperatures.

 - Cool and breezy conditions on Tuesday will be followed by a
   warm-up on Wednesday.

 - Low-end windy conditions are expected on the Caprock on
   Wednesday, with a cold front moving in late in the day.

 - Chilly and cloudy conditions are expected on Thanksgiving, with
   the possibility of some sprinkles.

&&

.SHORT TERM...
(Today and tonight)
Issued at 319 AM CST Mon Nov 25 2024

As of 2 AM CST, the cold front was pushing southward into the far
southern Texas Panhandle and expected to be through the South and
Rolling Plains by sunrise. Satellite imagery and observations reveal
a deck of low stratus pushing in behind the front across the
Oklahoma Panhandle and into the Texas Panhandle. There is low
confidence that these low clouds will make it as far south as the
far southern Texas Panhandle. However, there is a small potential
for some scattered low clouds across the northern portions of the
forecast area. Increased mid-level moisture in the westerly flow
aloft will continue to bring high clouds across the area from west
to east today. Post-frontal winds will be breezy out of the north
around 15 to 20 mph with higher gusts up to 30 mph possible at
times. Higher wind speeds of around 20 to 25 mph and locally higher
gusts may be possible across areas east of the Caprock Escarpment in
conjunction with increased wind speeds above the surface. As the
surface ridge digs south across the Central Plains today, the cooler
Canadian airmass will keep temperatures from warming much above the
lower 50s. A lack of low-level moisture with the front will give way
to continued dry conditions. By tonight, the surface ridge will dig
farther south into Oklahoma and northern Texas with diminishing wind
speeds as the north winds veer back to the south along with a return
of near or below freezing temperatures across much of the far
southern Texas Panhandle, South Plains and Rolling Plains.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 319 AM CST Mon Nov 25 2024

Mid/upper-level ridging will continue to dampen in amplitude on
Tuesday via the influence of a positively-tilted shortwave trough
digging into the northern Great Basin while a negatively-tilted
trough will be positioned over the northeastern U.S. The respective
cyclones surface-to-aloft associated with this negatively-tilted
trough will become vertically-stacked and rotate farther northward
into Quebec, with. This will allow the upstream trough to become
absorbed into a longer-wave trough that will evolve across the Lower
48 by Wednesday as its PV anomaly becomes increasingly stretched and
eventually dissipates as a northern-stream jet streak begins to
phase with the broad, cyclonically-curved, subtropical jet streak
arcing from the Desert Southwest to the northeastern U.S. by
Wednesday night. A high-frequency wavenumber pattern and its
associated negative momentum fluxes over the north-central Pacific
Ocean will maintain a series of cyclonically-breaking waves, which
is forecast to result in an amplification of the subtropical ridge
over the northeastern Pacific Ocean this weekend with the
possibility of a cut-off low forming offshore Baja California.
Longwave troughing is forecast to dominate the upper air pattern
across the central and eastern parts of North America throughout the
remainder of the period, with the CWA being positioned within the
inflection point of the ridge to the west.

On Tuesday, a 300 mb jet streak approaching 130 kt will translate
across the north-central Great Plains as the zonal flow begins to
modulate into the longer-wave trough. The belt of cross-barrier flow
in the mid-levels will approach 50 kt, resulting in lee cyclogenesis
across northeastern New Mexico. The airmass will have previously
been scoured of any moisture from the prior frontal passage;
however, the surface trough, initially anchored across eastern New
Mexico and intersecting the lee cyclone, will propagate eastward
throughout the day while the genesis of a quasi-stationary front
occurs via strengthening isallobaric response beneath the amplified
flow aloft. The net result will be an increase in southwesterly
winds, with speeds between 15-25 mph and gusts to 35 mph developing
by the late-morning and early-afternoon hours. Vertical mixing
heights are expected to be capped between 850-800 mb, owing to the
strong, mixed-layer theta-e advection as a result of the veered flow
within that layer. So, despite the breezy, southwesterly fetch, the
shallow boundary-layer heights, in addition to the modification of
the post-frontal air, will keep highs in the middle 60s area-wide.
The southwesterly breeze will remain intact heading into the
overnight hours as lee cyclogenesis continues, garnering a mild
night with lows in the upper 40s to lower 50s.

Geopotential height falls will become slightly-negative by Wednesday
as the upstream shortwave trough digs into the Four Corners region,
and begins its absorption into the larger waveguide spread across
the Lower 48. The lee cyclone will continue to rotate southeastward
into the Upper Red River Valley, with surface winds veering towards
the west in response. Winds were raised a few kt from the previous
assessments, with a 50-percent weighting applied to the NBM 90th
percentile, which closes in on the upper-bound of the statistical
guidance. By this point in time, the aforementioned 300 mb jet
streak should shift southward via influence of the PV anomaly
embedded within the approaching shortwave trough, further increasing
the intensity of the low- and mid-level flow. Vertical mixing
heights will also deepen compared to Tuesday and when combined with
the slightly-negative geopotential height falls, it will facilitate
low-end windy conditions, especially across the Caprock Escarpment.
Gusts up to 40 mph are forecast along and west of the HWY-385
corridor on Wednesday. Farther north, a cold front will be surging
southward across the TX PH, and is currently forecast to cross into
the far southern TX PH by the late-afternoon hours Wednesday. High
temperatures were also lowered a couple of degrees, as the thinking
is leaning towards a frontal progression that is a couple of hours
ahead of what the NBM reflects, in addition to the thickening cirrus
deck limiting the full effects of insolation. Additional adjustments
to the high temperatures and, more specifically, wind direction,
will be required in the forthcoming packages.

Regardless of an earlier arrival of the cold front on Wednesday, it
is forecast to clear the CWA shortly after sunset. Wind speeds will
remain elevated throughout the night following the spike in pressure
tendencies post-FROPA, with low temperatures on Thursday morning
nearly 15 degrees cooler than the prior morning. The shallow depth
of the post-frontal airmass beneath the belt of westerly flow
immediately above it should also result in near or total saturation
of the columns within the low- and mid-levels, and a few sprinkles
cannot be ruled out for portions of the Caprock Escarpment. Dense
overcast on Thursday will also restrict diabatic heating, and when
combined with what will be weakening CAA, high temperatures were
lowered a few degrees from the NBM with highs forecast to peak in
the upper 40s area-wide. Northeasterly winds will diminish quickly
by Thursday evening as pressure tendencies stabilize and a strong
surface high noses into the CWA from the north. The CWA is forecast
to remain within the inflection point of the longwave trough and the
amplifying subtropical ridge to the west, which will maintain high
temperatures closer to seasonal norms along with persistent cloud
cover. Another cold front is slated to move through the region by
Saturday as the northern-stream jet streak digs into the central
Great Plains, and the forecast remains dry for the weekend.

Sincavage

&&

.AVIATION...
(06Z TAFS)
Issued at 1038 PM CST Sun Nov 24 2024

A cold front currently moving southward through the TX Panhandle
will pass through the region overnight bringing a northerly wind
shift to all terminals during the 08-11z timeframe. Gusty north
winds will continue all day on Monday before gradually subsiding
during the afternoon. There is a low chance of some brief MVFR
CIGs during the hours following FROPA, but confidence in this
occurring is too low for TAF mention at this time. Otherwise, VFR
is expected to prevail through the next 24 hours.

&&

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

$$

SHORT TERM...11
LONG TERM....09
AVIATION...30