433
ACUS01 KWNS 160549
SWODY1
SPC AC 160547

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Thu May 16 2024

Valid 161200Z - 171200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON AND EVENING ACROSS PARTS OF CENTRAL AND SOUTHEAST TEXAS...

...SUMMARY...
Thunderstorms posing a risk for severe hail and wind may become
fairly numerous across parts of central and southeastern Texas this
afternoon into tonight.  A couple of tornadoes are also possible,
and an organized cluster of storms might eventually evolve by late
evening, accompanied by a more substantive risk for damaging wind
gusts.

...Synopsis...
Seasonably high moisture content has generally become suppressed
offshore of the southern Atlantic Seaboard through the central Gulf
of Mexico and lower Rio Grande Valley, in the wake of a surface
cyclone now centered offshore of the northern Mid Atlantic Coast.
The cyclone is forecast to weaken and migrate away from the coast,
as associated large-scale mid/upper troughing progresses east of the
Atlantic Seaboard through early Friday.  As this occurs, and
similar magnitude mid/upper troughing (at least initially) emerges
from the Southwest, low-level moisture appears likely to surge
northeast of the lower Rio Grande Valley toward the lower
Mississippi Valley.

Models do suggest that the Southwestern trough may progress
east-northeastward in somewhat piece-meal fashion, with perhaps one
notable perturbation accelerating across the Permian Basin by this
evening, preceded by one or two more subtle impulses.  Each will
tend to suppress mid/upper ridging now present across the southern
Great Plains, and may be accompanied by a substantive wave of
convective development.  However, the details of the potential
conglomerate convective evolution remain unclear, and convection
allowing model output is varied.

...Texas...
While the influence of early period convection and associated
outflow on the low-level environment remains uncertain, model output
is suggestive that a fairly well-defined lower/mid-tropospheric
baroclinic zone (around 700 mb) may provide the primary focus for
stronger convective development during this period.  In the wake of
at least one initial short wave perturbation, and in advance of the
more prominent one, this will likely demarcate the northern
periphery of the warmer and more strongly capping elevated
mixed-layer air.  By late this afternoon, it is possible that a zone
of differential surface heating may become better defined beneath
this regime, from portions of the Pecos and Rio Grande Valleys into
central Texas.

Along and south of this zone, it appears that mixed-layer CAPE will
become large (on the order of 2000-4000 J/kg), beneath seasonably
strong southwesterly upper flow.  Deep-layer shear likely will be
supportive of supercells, aided by veering with height of initially
modest low-level wind fields which are forecast to strengthen by
this evening across central into southeastern Texas.

Large hail and locally damaging wind gusts appear the primary severe
threat with initial eastward/southeastward propagating supercells by
late afternoon.  As low-level hodographs enlarge, the risk for a
couple of tornadoes may increase by this evening in both lingering
supercells and upscale growing convection.  At least one prominent
cluster may gradually evolve and organize across central into
southeastern Texas by late this evening, accompanied by increasing
potential for damaging wind gusts.

..Kerr/Squitieri.. 05/16/2024

$$