491
FXUS64 KLUB 061724
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1224 PM CDT Sat Jul 6 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 314 AM CDT Sat Jul 6 2024

07Z upper air analysis depicts a shortwave trough pivoting over the
central and eastern portions of the U.S., with several smaller-scale
perturbations and vorticity maxima translating through the belt of
amplifying flow in the mid-levels as per recent water-vapor imagery.
Farther west, a subtropical, mid/upper-level ridge continues to
amplify over the western U.S. as a baroclinic low over the northern
Pacific Ocean becomes vertically-stacked. The superposition of these
features has maintained northwesterly flow in the mid-levels while
the right entrance-region to the 250 mb jet remains over the
southern Great Plains. An ill-defined shortwave perturbation
translating over the Sangre de Cristo Mountains has also generated a
band of elevated convection that was propagating southeastward
towards the CWA, though it is not particularly well-organized based
on trends in recent KAMA WSR-88D imagery with only a few cores
remaining intact. PoPs throughout the remainder of the overnight
hours through 15Z have been left intact as the multi-cellular line
of storms continues to propagate southeastward towards the NM/TX
state line; however, spatial coverage of storms should be limited
owing to the magnitude of subsidence aloft as observed by the 06/00Z
RAOB from WFO AMA.

At the surface, an anticyclone was centered in JTN with the cold
front far removed from the CWA and near the I-10 corridor based on
recent METAR and West Texas Mesonet (WTM) data. GOES-East Nighttime
Microphysics imagery detects a few areas of low stratus beginning to
develop across the southern South and Rolling Plains, though anvil
debris associated with thunderstorms in the Big Bend has somewhat
obscured this view. The expectation is for low stratus to steadily
form over the next few hours across portions of the CWA as the
southeasterly fetch and related adiabatic expansion causes the lower
boundary-layer to reach its saturation point. The surface high will
also rotate eastward throughout the remainder of the morning and
into the afternoon, with surface winds becoming southerly area-wide
with clouds eroding by early-to-mid-afternoon. Temperatures will
warm into the upper 80s across the CWA as well, and subsidence from
veered/westerly flow at 700 mb that becomes northwesterly above will
cap vertical mixing heights and prevent any further adiabatic
warming today. PoPs were removed for this afternoon due to the lack
of surface and low-level convergence, and as the diurnally-driven cu
field is entrained by dry air as parcels ascend from the LFC. The
southerly breeze will increase throughout the overnight hours as lee
cyclogenesis continues across southeastern Colorado beneath the
amplifying shortwave trough and as the exit-region of an upstream
250 mb jet streak noses into the western High Plains, resulting in a
warmer morning on Sunday compared to this morning.

Sincavage

&&

.LONG TERM...
(Sunday through Friday)
Issued at 314 AM CDT Sat Jul 6 2024

The mid/upper-level, subtropical ridge over the western U.S. is
forecast to deamplify on Sunday morning as the baroclinic low over
the northern Pacific Ocean begins to become neutrally-tilted and
start its transition into an open trough. The net result of this
synoptic-scale evolution upstream of the CWA will cause the broadly
cyclonic troughing to deepen and attain a positive-tilt, and will be
further aided by the coupling of a 250 mb jet streak extending
southward out of Saskatchewan. Cold frontogenesis will occur at the
surface and low-levels, with the frontal movement expected to be
convectively-reinforced by a Mesoscale Convective System (MCS) along
the front as it moves southward across the central Great Plains.
Ahead of the cold front, hot temperatures near 100 degrees are
expected to occur as the eastern periphery of the Pacific ridging
eclipses the CWA, with 850 mb temperatures approaching 30 deg C. The
airmass will become uncapped by this point with boundary-layer
mixing heights ascending to near or above 700 mb which will
galvanize an Inverted-V profile as southerly flow strengthens to
around 20 mph by peak heating.

PoPs were increased from the blended initialization across the
Rolling Plains given the expectation for potentially widespread
thunderstorms to form along the cold front as it surges southward
across the southern Great Plains. How far west convection unzips
remains unclear and the blended PoPs were maintained across the
Caprock, and it is possible that a dry passage occurs across the
Caprock. Blowing dust may accompany this front especially due to the
possibility of its movement being reinforced by thunderstorm
outflow. Anomalously high precipitable water (PWAT) content, in
addition to a belt of high theta-e air advecting poleward towards
the southward-surging front beneath the right entrance-region to the
250 mb jet streak, will lead to the potential for heavy rainfall and
flash flooding, particularly across the Rolling Plains, on Sunday
night. PWAT content in excess of 1.50" is forecast across the
Rolling Plains during this time, and rain rates between 1-2"/hr will
be possible; however, the progressive movement of the front and an
unfavorable alignment of the Corfidi vectors for back-building will
temper a more-significant flash flood potential.

Post-frontal, elevated showers and thunderstorms may persist into
Monday morning and afternoon across portions of the CWA as an
intense shortwave trough digs into the central Great Plains and the
entrance-region to the 250 mb jet streak further amplifies. The
favorable ascent profile throughout the column (i.e., easterly,
upslope, low-level flow; and divergent mid- and high-level flow in
vicinity of the right entrance-region of the jet streak to the north
of Tropical Cyclone Beryl) yields enough confidence to maintain PoPs
through Monday night. Much cooler temperatures are also forecast on
Monday, with temperatures in the upper 70s to lower 80s expected as
dense overcast restricts diabatic heating. The mid/upper-level
shortwave trough is forecast to translate northeastward by Tuesday,
and the resultant NVA on the backside of the trough combined with
the subsidence to the west of the remnants of TC Beryl leads to a
dry forecast for most of the day with the exception of areas nearest
the TX/NM state line.

Subtropical ridging is once again forecast to amplify over the
Desert Southwest on Tuesday, and diurnally-driven convection across
eastern NM generated by weak perturbations translating along the
eastern periphery of this ridge may propagate southeastward into the
western South Plains late Tuesday evening before the potential wanes
after the boundary-layer decouples. Renewed chances for storms will
return Wednesday and Thursday afternoon across the Caprock as
northwesterly flow aloft remains intact before drying out towards
the end of the week as the subtropical ridge shifts eastward
followed by a warming trend.

Sincavage

&&

.AVIATION...
(18Z TAFS)
Issued at 1215 PM CDT Sat Jul 6 2024

VFR expected next 24 hours. There exist a low risk of thunderstorm
activity, primarily N/NW of KPVW late this afternoon into the
evening hours. Thermal turbulence will be quite prevalent (and
noticable) during the afternoon until the cumulus clouds start to
disappear around sunset. Increasing storm chances, particularly at
KCDS, are indicated just after the valid time of this TAF cycle.

&&

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

$$

SHORT TERM...09
LONG TERM....09
AVIATION...26