SPC Dec 15, 2023 0700 UTC Day 2 Convective Outlook

[NorthGeorgiaWX]

SPC 0700Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1255 AM CST Fri Dec 15 2023

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
FLORIDA PENINSULA...

...SUMMARY...
Severe thunderstorms are possible across the Florida Peninsula
overnight Saturday night into Sunday morning. Damaging gusts and a
few tornadoes are possible.

...Synopsis and Discussion...
Upper troughing is expected to extend from the Dakotas/MN border
south-southeastward into the western Gulf of Mexico early Saturday
morning. Several shortwave troughs will be embedded within the this
upper trough, with the southernmost shortwave over TX early
Saturday. This southern wave is forecast to continue progressing
eastward/southeastward throughout the period, while a pair of
northern shortwaves evolve into a closed mid-latitude cyclone over
the Mid MS Valley. This evolution results in a more neutral tilt to
the larger upper trough by Saturday evening, and a slightly negative
tilt by early Sunday morning. 

Large-scale ascent and mass response ahead of the southern shortwave
trough will contribute to strong surface cyclogenesis over the
central and eastern Gulf, with the resulting low approaching the FL
Peninsula late Saturday night/early Sunday morning. Guidance
continues to show notably large differences (i.e. 400 to 500 km) in
the location of this surface low early Sunday morning. These
differences result in more forecast uncertainty than is typical at
this forecast range. The faster solutions are favored at this time,
particularly the HREF and Canadian, placing the surface low over the
central FL Peninsula at 12Z Sunday.

A low-amplitude, convectively enhanced vorticity maximum will
precede this surface low (and parent surface low), contributing to
numerous showers and thunderstorms across the peninsula, beginning
late Saturday afternoon. Resultant warm mid-level temperatures will
temper overall buoyancy, even as upper 60s/low 70s dewpoints move
over south FL late Saturday night/early Sunday morning. This should
limit updraft strength within the confined warm sector over south FL
throughout much of the night. However, as the low continues
northeastward, the combination surface convergence and large-scale
ascent within this modestly buoyant environment should be able to
support deeper updrafts, and perhaps even the development of a
convective line. Damaging gusts are possible with any deeper, more
sustained convection. Veering low-level hodographs could also
support the potential for a few tornadoes. Most likely location for
severe weather will be in the vicinity of the surface low, which is
expected to move across the central portion of the peninsula.

..Mosier.. 12/15/2023

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