979
FXUS64 KLUB 191731
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1231 PM CDT Sun May 19 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 240 AM CDT Sun May 19 2024

06Z upper air analysis depicts a dampening shortwave ridge
propagating over the southern Great Plains and within the southern
tranche of a synoptic-scale, split-flow regime encompassing the
central and western portions of the U.S. The 00Z objectively
analyzed upper air maps observed a 250 mb jet streak near 100 kt
over the Gulf of Santa Catalina and stretching towards the Mogollon
Rim, and this feature was currently nosing over northwestern New
Mexico as per recent water-vapor imagery. Upstream influence from
the broadly cyclonic flow has resulted in the dampening of the
shortwave ridge as it propagates east of the CWA, and the backside
of it should clear east of the 100th meridian after sunrise. At the
surface, the retrograding of the lee cyclone has positioned it in
the vicinity of TCC as per METAR and West Texas Mesonet (WTM) data,
with a northwest-to-southeast-oriented dryline bisecting the CWA
along a line from CVS-LBB-SNK based on recent WTM data. Dewpoints
within the moist sector were near 65 degrees in the eastern Rolling
Plains, while a dewpoint spread of nearly 20 degrees exist across
the dryline from New Deal to Reese Center where flow veers to the
south on the western periphery of the dryline. There is no
indication of a nocturnal wind maximum on LIDAR from LBB this
evening, and 850 mb winds were benign on the 19/00Z RAOBs from AMA
and MAF as the apex of the shortwave ridge passed overhead.

Gradual deepening of the lee cyclone is expected to occur after 12Z
as it rotates from near TCC towards GUY in the OK PH. The sharpening
dryline will propagate accordingly across the Caprock and into the
eastern Rolling Plains as large-scale, geostrophic deformation
increases aloft ahead of the emergence of the leading mid-level
shortwave trough this afternoon. 19/00Z RAOBs upstream of the CWA at
ABQ and EPZ sampled a deeply-mixed boundary-layer profile, with
superadiabatic lapse rates within the surface-to-3-km layer. (AMA
and MAF RAOBs also sampled a similar profile.) Therefore, a similar
boundary-layer profile as observed yesterday will evolve once again
today, with intense dry-bulbing expected as temperatures soar into
the middle 90s to near 100 degrees across the CWA. As the depth of
the boundary-layer ascends into the mid-levels, the arrival of the
700 mb trough, in addition to the leeward pressure falls associated
with the deepening cyclone in the OK PH, will result in an increase
in southwesterly winds to around 15-30 mph across the Caprock while
becoming backed to the south in the Rolling Plains to the east of
the dryline. Although the orientation of deep-layer flow favors a
supercell wind profile, the forecast has been kept dry for this
afternoon in the Rolling Plains as parcels are expected to struggle
against the deleterious effects of dry air entrainment upon reaching
the LFC, especially given the magnitude of flow parallel to the
dryline and low relative humidity content within the lowest 150 mb
of the boundary-layer. A few congested cu may develop along the
dryline; however, substantial dilution of parcels should occur even
as CINH erodes from intense heating given the latter thinking.

The dryline will retreat westward upon the cessation of vertical
mixing this evening, and should orient in a southwest-to-northeast
position as a well-defined bulge is maintained in the TX PH nearest
the lee cyclone. Surface winds will steadily diminish thereafter to
10-15 mph while veering southwestward, with low temperatures heading
into Monday morning ranging from the middle 50s to the lower 70s
from across the extreme southwestern TX PH and into the southeastern
Rolling Plains, respectively.

Sincavage

&&

.LONG TERM...
(Monday through Saturday)
Issued at 240 AM CDT Sun May 19 2024

Flat upper level short wave ridging will be overhead on Monday with
dry southwesterly flow at the surface will lead to another hot day
with high temperatures similar to today, although with potential off
the Caprock to push into triple digits with the veered winds
relative to today. Upper ridging shifts to the east Monday night as
a broad upper trough over the western CONUS begins to open up and
move over the Great Plains led by the first short wave trough
ejecting across the central High Plains on Monday night and the
second, more significant trough ejecting onto the central High
Plains Tuesday night. This overall evolution will begin to cool
things down Tuesday (on the order of 5 to 7 degrees) as geopotential
heights and thicknesses fall with more substantial cooling on
Wednesday as a cold front is allowed to spill southward as the
second trough moves over the High Plains. The Thursday to Saturday
period will be marked by a transition back toward low-amplitude
upper level ridging, although a this time progged heights and
thicknesses suggest peak temperatures remaining below those of this
weekend. Precipitation chances continue to look confined to the
eastern third to half of the forecast area on Thursday. North to
northeast winds across the area on Wednesday with the cold front
fairly well to the south of the forecast area suggests convective
initiation will be south of the area with the NBM slight chance
mention Wednesday afternoon and evening still looking a bit
aggressive. However, low to mid level warm advection as low level
flow quickly veers to southeast Wednesday night and ahead of a low
amplitude short wave trough continue to point toward decent shower
and thunderstorm chances Thursday morning then shifting eastward as
early as early to mid afternoon hours.

&&

.AVIATION...
(18Z TAFS)
Issued at 1229 PM CDT Sun May 19 2024

VFR will persist through the TAF period. LLWS will develop at KCDS
for a brief period early Monday morning as surface winds relax
while winds just off the deck remain strong.

&&

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

$$

SHORT TERM...09
LONG TERM....07
AVIATION...01