ACUS02 KWNS 150453
SWODY2
SPC AC 150452

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1152 PM CDT Thu Mar 14 2024

Valid 161200Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SATURDAY THROUGH
SATURDAY NIGHT ACROSS SOUTH CENTRAL AND SOUTHEASTERN TEXAS...

...SUMMARY...
Strong storms may impact portions of south central and southeastern
Texas Saturday through Saturday night, accompanied by at least some
risk for severe weather.

...Synopsis...
In general, models indicate further amplification of the large-scale
flow across North America through this period, including the
evolution of a high within prominent building mid/upper ridging
across the Pacific Northwest through much of the western Canadian
Provinces. Downstream of this ridging, large-scale troughing is
forecast to continue to evolve across much of eastern Canada and the
northern tier of the eastern U.S., with one significant short wave
perturbation digging into the Upper Midwest/Red River Valley
vicinity, in the wake of another accelerating across and east of the
lower Great Lakes.

To the south-southeast of the developing high, it appears that a
mid/upper low will begin to weaken while remaining quasi-stationary
across the Southwest. However, at least one notable embedded
perturbation may gradually pivot around the southwestern through
southern periphery of the circulation center, across the
international border area by 12Z Sunday. At the same time, a short
wave trough emerging from the subtropical eastern Pacific may
progress through cyclonic flow to the south, across the Mexican
Plateau into the Rio Grande Valley by late Saturday night, preceded
by more subtle impulses progressing into and through the crest of
low amplitude subtropical ridging across the Gulf coast vicinity.

In lower-levels, a weak surface front, reinforced by convective
outflow, appears likely to stall and weaken across the northeastern
and north central Gulf coast vicinity, southwestward into the lower
Rio Grande Valley, while a more significant cold front surges from
the north Great Plains/Upper Midwest and Great Lakes into and
through the Ohio and middle Mississippi Valleys.

...Southern Texas...
Model spread, concerning some of the short wave developments through
this period, continues to contribute to at least some uncertainty
concerning convective potential for Saturday through Saturday night.
Inhibition associated with elevated mixed-layer air may also
continue to be a factor, particularly where a lingering moist
unstable boundary becomes unstable with daytime heating, across
parts of the lower Rio Grande Valley and coastal plain.

However, guidance is suggestive that destabilization and lift along
the leading edge of the warmer elevated mixed-layer air may
contribute to vigorous thunderstorm development by midday Saturday,
as it retreats back northeastward across south central Texas through
the upper Texas coastal plain. Although this may be mostly rooted
above stable near-surface lapse rates, steep lapse rates farther
aloft may support sizable CAPE in the mid to upper levels, and
promote a risk for large hail in the presence of strong convective
layer shear.

In the wake of this early day convection, at least some model output
is suggestive that a corridor of stronger daytime heating may
overcome inhibition and allow for a period of boundary-layer based
thunderstorm development late Saturday afternoon and evening,
roughly from around College Station into areas south of San Antonio.
This could include one or two supercells accompanied by some risk
for a tornado, in addition to large hail, before weakening, though
low-level hodographs are forecast to remain relatively modest to
weak.

Thereafter, forcing for ascent associated with the subtropical short
wave perturbation crossing the Mexican Plateau into Rio Grande
Valley may contribute to renewed vigorous convective development
late Saturday night across south central Texas. This activity will
probably be elevated, rooted within ascent associated with lower/mid-tropospheric warm advection, but the environment may
remain conducive to a risk for severe hail.

..Kerr.. 03/15/2024

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