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ACUS02 KWNS 200450

SWODY2

SPC AC 200448



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1148 PM CDT Tue Mar 19 2024



Valid 211200Z - 221200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY INTO

THURSDAY NIGHT ACROSS PARTS OF CENTRAL AND SOUTHEAST

TEXAS...SOUTHERN LOUISIANA...



...SUMMARY...

Strong thunderstorms may impact parts of central and southeast Texas

into coastal Louisiana on Thursday.  One or two organizing clusters

could evolve, accompanied by at least some risk for severe weather.



...Synopsis...

Downstream of a blocking regime centered across the northeastern

Pacific, it appears that split westerlies will continue to trend

more zonal to the east of the Rockies, in the wake of a deep,

occluding cyclone migrating northeastward across the Canadian

Maritimes.  Models suggest that the shallower leading edge of a

significant cold intrusion trailing the cyclone will stall and

undergo considerable modification across the southern Mid Atlantic,

Tennessee Valley, Ozark Plateau and central Great Plains, into the

lower Missouri and Ohio Valleys by late Thursday night.



In the wake of a preceding front, relatively cool conditions appear

likely to be maintained across much of the southeastern Great Plains

into northern Gulf coast vicinity, beneath increasingly widespread

mid/high-level cloudiness and associated light to moderate rain

falling into an initially dry/potentially cool boundary layer.  This

will precede one notable short wave perturbation emanating from the

subtropical eastern Pacific (readily evident in current satellite

imagery approaching Baja), and a remnant short wave perturbation

forecast to emerge from the Southwest.  



There has been considerable spread evident in the various model

output concerning the emerging remnants of the closed from the

Southwest, as a persistent block inland of the Pacific coast breaks

down.  Guidance has trended notably more sheared with an initial

perturbation forecast to accelerate east of southern Rockies through

the Texas Panhandle region late Wednesday into early Thursday.  But

it still appears that a trailing perturbation may become better

defined and accelerate eastward within stronger mid-level flow,

across the Permian Basin/Texas Big Bend into the northwestern Gulf

coast by 12Z Friday.



Forcing associated with the trailing perturbation may contribute to

a developing frontal wave across the upper Texas into Louisiana

coastal plain, but guidance continues to suggest that this will

remain weak through this period.



...Texas...

It still appears that moderate boundary-layer CAPE will develop, in

association with moistening beneath warm and capping elevated

mixed-layer air across the lower into middle Texas coastal plain by

early Thursday.  However, the continued northward advection of this

boundary-layer moisture, and associated destabilization, is now more

unclear in latest model output.  



Forcing for ascent associated with the subtropical perturbation is

generally forecast to reach middle into upper Texas coastal areas

Thursday morning through midday, if not earlier.  And it appears

possible that this could support initially strong to severe

thunderstorm development, including supercells, before convection

consolidates into cluster and progresses offshore along a developing

warm frontal zone across the northwestern Gulf of Mexico.



In the wake of this convection, daytime heating within at least a

modestly moist boundary-layer probably will contribute to at least

weak CAPE in a corridor from middle Texas coastal areas into the

Interstate 35 corridor of central Texas.  As the mid-level cold core

(-18 to -20C) of the perturbation emanating from the Southwest

overspreads this region Thursday evening, renewed vigorous

thunderstorm development appears possible.  Strong deep-layer shear

may contribute to a risk for supercells initially, with at least

some potential for the evolution of an organizing cluster

overspreading the upper Texas into Louisiana coastal plain Thursday

night.



It is still possible that severe probabilities could be increased

across parts of central into southeastern Texas in later outlooks,

once the sub-synoptic developments become better resolved.



..Kerr.. 03/20/2024



$$