038
FXUS64 KLUB 070813
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
313 AM CDT Sun Jul 7 2024

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

.SHORT TERM...
(Today and tonight)
Issued at 313 AM CDT Sun Jul 7 2024

06Z upper air analysis reveals a shortwave trough pivoting across
the central Great Plains with a small, vertically-stacking low
located over the MN/ND border. Several other smaller-scale
perturbations were also evident on water-vapor imagery as the
broadened waveguide of the trough extends from the northern Rocky
Mountains into the Great Lakes region, with an elongated ribbon of
vorticity emanating from the apex of the subtropical ridge that is
centered over the Sacramento Valley. The mid-level cold front
associated with the stacking low branched southward into western
Kansas before it becomes increasingly ill-defined aloft with
southward extent into the TX PH. Subsidence continues to advect
overhead this morning as the CWA remains within the inflection point
of the broad trough and the subtropical ridge to the west, with this
distinct subsidence layer observed by the 07/00Z RAOB from WFO ABQ.
The orientation of the synoptic-scale flow and related subsidence
over the CWA will continue to shunt the upper-level outflow channel
from T.C. Beryl to the southeast and east of the CWA. The tropical
system will not have an influence on the thunderstorm potential
later today and into Monday as the right entrance-region to the 250
mb jet streak remains superposed over the region through end of the
short-term period owing to the blocking of the subtropical ridges
over the western U.S. and eastern Atlantic Basin.

At the surface, a fairly active pattern has been analyzed with a
double cold front structure evident in the central and southern
Great Plains, both of which are currently north of the CWA. Multiple
surface troughs were also evident on recent METAR and West Texas
Mesonet (WTM) data, with WTM data delineating a surface trough west
of the edge of the Mescalero Escarpment, another one located east of
the 100th meridian; and a convectively-contaminated, pre-frontal
surface trough located near the OK PH. Two lee cyclones were also
located near the Raton Mesa and the other in north-central Kansas.
The deepening of these lee cyclones, in addition to the slightly
negative geopotential height falls, has resulted in southerly winds
increasing to the 15-25 mph, particularly across the Caprock, as per
recent WTM data. Breezy, southerly winds are expected to remain
intact through sunrise before gradually veering southwestward later
this morning as the lee cyclone that is currently near the Raton
Mesa rotates eastward into the TX PH and its annexed surface trough
translates towards the NM/TX state line. Veering of the surface flow
will enhance the effects of adiabatic compression amidst intense
heating from full insolation, and temperatures are forecast to near
100 degrees this afternoon while the 65 degree isodrosotherm lingers
across the Rolling Plains as winds remain backed to the south ahead
of the surface trough.

As the southwest-to-northeast-oriented surface trough sloshes into
West Texas this afternoon, surface and low-level convergence will
begin to increase considerably along and northeast of the I-27
corridor as convective temperatures are reached. The superposition
of the right entrance-region to the 250 mb jet streak will also
provide enough large-scale forcing for ascent during the early and
mid-afternoon hours (i.e., a few cirrus bands will likely be
observed advecting in from the northwest as the ribbon of increasing
DCVA approaches the CWA). Similar to what was observed last evening
by the neighboring 00Z RAOBs, a deeply-mixed boundary-layer is
expected with LCLs near 700 mb. Initial attempts at thunderstorm
initiation will be isolated-to-widely-scattered after 18Z, though
steep, mid-level hydrolapses ahead of the convectively-reinforced,
southward-surging cold fronts should keep storms cellular with the
possibility of semi-discrete propagation during the mid-afternoon
hours. More-scattered to potentially widespread convection is
forecast to develop later this evening as the cold front arrives,
with the highest potential for heavy rain and severe-caliber wind
gusts occurring across the Rolling Plains.

Precipitable water (PWAT) content near 1.5" in the open warm sector
and warm-cloud depths nearing 14 kft AGL beneath the right-entrance
region to the 250 mb jet streak will galvanize the potential for
heavy rain across the Rolling Plains. The progressiveness of the
cold front and misalignment of the Corfidi vectors for upwind
propagation will temper a more-significant flooding risk; however,
rain rates as high as 2"/hr will accompany the deepest cores across
the Rolling Plains. PoPs were once again raised from the blended
initialization for locales in the Rolling Plains (i.e., 80 percent
in the official forecast), with storm chances diminishing onto the
Caprock while a dry forecast maintained west of the I-27/HWY-87
corridors. Reinforcement via convective outflow may cause the cold
front to accelerate in forward-speed, with the MCS exiting the CWA
perhaps as early as 08/05Z (midnight CDT) tonight.

Renewed chances for showers and thunderstorms will follow after the
passage of the initial MCS/cold front as the 250 mb jet streak near
70 kt that was analyzed on the 07/00Z upper air map data digs into
the southern Rocky Mountains, and as the upstream jet streak
amplifies as another well-defined shortwave trough digs into the
north-central Great Plains. The net increase in moist, isentropic
ascent; and associated DCVA at the base of the sharpening trough,
should result in at least scattered showers and thunderstorms
heading towards sunrise Monday with the reservoir of PWATs
potentially being convectively-augmented by the prior MCS as
easterly, upslope flow develops in the wake of the cold front. Heavy
rainfall will be possible, particularly with bands of post-frontal,
elevated thunderstorms that become organized as warm-cloud depths
remain near 13 kft AGL up onto the Caprock Escarpment towards
sunrise on Monday.

Sincavage

&&

.LONG TERM...
(Monday through Saturday)
Issued at 313 AM CDT Sun Jul 7 2024

A broad shield of rain is forecast to linger over portions of the
CWA after sunrise on Monday, with rainfall coverage and intensity
gradually dissipating by the late-afternoon hours as the base of the
mid/upper-level trough begins to move east of the CWA. Easterly flow
will remain intact throughout the course of the day, further aiding
in adiabatic expansion and moist, isentropic ascent to maintain at
least light rain showers through the evening. Subsident warming of
the mid-levels will also gradually erode the depth of the elevated
mixed layer, with most-unstable parcels yielding less than 750 J/kg
by Monday evening across portions of the Caprock and Rolling Plains.
Total rainfall accumulations will vary immensely across the CWA,
with the lowest amounts forecast across the southwestern South
Plains compared to areas farther east and northeast. The dense
overcast and rain-cooled airmass will also keep high temperatures in
the middle 70s across most of the CWA with the exception of
locations near the 100th meridian where lower 80s are forecast.
Coverage of thunderstorms will become more-isolated after sunset
Monday, with convection ending altogether before daybreak Tuesday.

The subtropical ridge to the west of the region is forecast to
amplify on Tuesday as it drifts eastward over the Great Basin.
Temperatures will warm into the upper 80s as the dense overcast
erodes and advects eastward entirely, and winds will be light and
variable as the weak surface anticyclone remains anchored across the
southern Great Plains. Northwesterly flow will persist aloft on
Tuesday and Wednesday, with diurnally-driven thunderstorms forecast
to occur each day across eastern NM. The cells may propagate near or
into the western zones each evening, but confidence in this remains
low as the magnitude of the steering flow remains dampened and
similar to what has been observed in prior days (e.g., near 15 kt).
The blended PoPs were trimmed to the west of the HWY-385 corridor
for Tuesday evening while being maintained across most of the
Caprock for Wednesday evening. Temperatures will continue to
steadily warm throughout the week as well as the center of the
subtropical ridge rotates eastward towards the Four Corners,
resulting in a gradual increase in geopotential heights with the
forecast remaining dry heading into next weekend.

Sincavage

&&

.AVIATION...
(06Z TAFS)
Issued at 1117 PM CDT Sat Jul 6 2024

VFR conditions are expected to prevail through the period.
Increasing storm chances are expected at all TAF sites by late
Sunday afternoon, with the highest confidence for storms being at
KCDS. Stronger storms may lead to gusty and erratic winds in
addition to frequent lightning and reduced visibility from
localized heavy rainfall.

&&

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

$$

SHORT TERM...09
LONG TERM....09
AVIATION...12