SPC 0600Z Day 2 Outlook
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
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