SPC May 13, 2024 1300 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0749 AM CDT Mon May 13 2024

Valid 131300Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
SOUTH-CENTRAL/SOUTHEAST TEXAS AND THE GULF COAST...

...SUMMARY...
Severe thunderstorms are expected today from central and east Texas
across the Gulf Coast states. The potential exists for multiple
corridors of significant wind gusts, very large hail, and a few
tornadoes.

...Central/eastern Texas...
The region will be influenced by moderately strong cyclonically
curved westerlies within the base of the central Plains/Lower
Missouri Valley-centered upper-level trough. Some northward spread
of a very moist near-coastal air mass will occur today ahead of an
upstream southeastward-moving cold front and weak surface wave.
Beneath steep mid-level lapse rates (reference 12z observed
soundings from DFW/CRP), strong destabilization is expected into the
afternoon as multi-layer cloud cover becomes more scattered, with
upwards of 2000-4000 J/kg MLCAPE across much of south-central and
east/southeast Texas.

A belt of stronger mid-level flow will overspread the region, with
elongated, straight hodographs supporting splitting supercells as an
initial storm mode. Large hail will be the main threat with these
storms, with some of the largest stones potentially reaching 2-4
inches in diameter where sustained supercell structure can develop
and persist. With time, storms should grow upscale into an
east/southeastward-moving MCS later in the afternoon and evening as
they move toward the coastal plain and interact more favorably with
the baroclinic boundary. By this point, severe gusts become the
primary threat, with a couple of QLCS tornadoes also possible.

...Gulf Coast/Southeast...
A quasi-linear storm cluster persists this morning across far
southern Alabama and the Florida Panhandle, on the immediate cool
side of a near-coastal warm front that will continue to develop
north-northeastward through the day. This cluster may grow further
upscale with a continued severe risk through the morning,
particularly with 75-100 miles of the Gulf of Mexico. This includes
the potential for all severe hazards including damaging winds, large
hail and some tornado risk. Additional storm development and
intensification is possible today along the outflow reinforced
effective front that extends westward across far southern
Mississippi and southern Louisiana.

Additionally, linearly organized storms moving out of Texas could
approach some of these same areas again late tonight. Any such
secondary/tertiary rounds of severe risk will depend upon how far
south the effective baroclinic zone has been shunted southward by
convection through the afternoon/early evening, likely confining any
such severe potential late tonight to more immediate coastal areas.

...Portions of the southern Plains into the Ozarks...
Showers and thunderstorms should linger across much of the southern
Plains into the Ozarks this morning to at least mid-afternoon. Weak
surface low development is anticipated across Missouri/Arkansas
later in the day, which will encourage modest low-level moisture
advection beneath gradually steepening mid-level lapse rates. SBCAPE
should rise into the 1000-1500 J/kg range later in the afternoon.
Deep-layer shear is not expected to be overly strong with northward
extent, though some elongation of straight hodographs suggests that
multicells or brief, transient supercells may develop and produce
isolated severe hail and/or wind.

...Florida Peninsula...
To the south of potential MCS influences across northern Florida,
surface temperatures are expected to rise into the 80s F amid
dewpoints around 70 F. Though mid-level lapse rates will be
relatively poor, the strong surface heating of the moist air mass
will boost SBCAPE into the 1000-2000 J/kg range amid 30-40 kt of
effective bulk shear. Multicells and transient supercells are
expected to initiate during the afternoon, especially along
sea-breeze boundaries, with isolated instances of hail and damaging
winds gusts possible.

...Northern Montana...
A few strong storms could occur from mid-afternoon through early
evening, influenced by a low-amplitude mid-level disturbance and a
modestly moist/unstable boundary layer. Some stronger wind
gusts/hail could occur, but modest-strength low/mid-tropospheric
winds should keep organized severe potential low.

..Guyer/Broyles.. 05/13/2024

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