SPC Dec 8, 2023 1730 UTC Day 2 Convective Outlook

[NorthGeorgiaWX]

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1130 AM CST Fri Dec 08 2023

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST
TX INTO THE TN VALLEY...

...SUMMARY...
Severe thunderstorms capable of producing a few tornadoes, scattered
damaging winds, and large hail will be possible from east Texas to
the Tennessee Valley, mainly Saturday afternoon and evening.

...Synopsis...
A deep, positively tilted upper-level trough will move eastward
across parts of the central/eastern CONUS on Saturday. Within the
larger-scale trough, an upper-level cyclone initially over MN will
evolve into a shortwave that moves eastward through the day, as a
surface low moves quickly northeastward from the Great Lakes region
toward Hudson Bay. A trailing low-amplitude shortwave trough will
deamplify as it moves from the southern Rockies toward the lower/mid
MS Valley. A cold front will move across the southern Plains and
eventually into parts of the Southeast, with weak surface wave
development possible during the day near the ArkLaTex region. 

...East TX into the TN Valley...
In advance of the cold front, relatively rich low-level moisture
will be in place across parts of TX/LA Saturday morning, and stream
northward into parts of the Southeast and TN Valley through the day.
Modest diurnal heating will support moderate destabilization from
east TX into the ArkLaMiss region (MLCAPE increasing into the
1000-1500 J/kg range), with more modest buoyancy (MLCAPE to near 500
J/kg) potentially extending as far north as southern KY. Meanwhile,
increasing deep-layer flow/shear in advance of the approaching upper
trough will support long hodographs and increasingly favorable wind
profiles for organized convection across the warm sector.

Surface-based thunderstorms are expected to increase in coverage
Saturday afternoon along and perhaps somewhat ahead of the
approaching front, as low-level moistening continues and MLCINH is
eroded. Effective shear of 50+ kt will be more than sufficient for
supercells, though with deep-layer flow largely parallel to the
front, a tendency toward a cluster and/or linear mode is expected
with time. Large hail will be possible with any sustained
supercells. Also, increasing low-level shear will be sufficient to
support a tornado threat with any supercells that can be sustained
from late afternoon into the evening, especially if a stronger
frontal wave can develop. Otherwise, damaging wind and possibly
embedded brief tornadoes may become the primary threat Saturday
night as storms move eastward, with a gradual weakening trend
expected due to diminishing buoyancy. 

Severe probabilities were expanded northeastward somewhat with this
outlook, due to the potential for a couple longer-lived supercells
or organized bowing segments to persist into the evening. Higher
probabilities were trimmed across parts of east TX, where capping
and weaker large-scale ascent are expected to limit storm coverage.

..Dean.. 12/08/2023

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