SPC Dec 15, 2023 1730 UTC Day 2 Convective Outlook

[NorthGeorgiaWX]

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1121 AM CST Fri Dec 15 2023

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY
EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND 
SOUTHERN FLORIDA PENINSULA AND KEYS...

...SUMMARY...
Strong thunderstorms may impact the Florida Peninsula and Keys
Saturday night, with a few possibly becoming severe and posing a
risk for tornadoes and damaging wind gusts.

...Synopsis...
Stronger, more zonal westerlies will remain confined to the northern
mid-latitudes through this period, while flow remains more amplified
in lower latitudes.  The latter regime will include a broad and
deep, occluded cyclone over the southern mid-latitude eastern
Pacific and prominent downstream mid/upper ridging across the
Pacific coast and much of the Intermountain West.

Farther downstream, developments, particularly in the shorter
wavelengths, remain more unclear.  The axis of mean larger-scale
mid-level troughing is forecast to dig across and east-southeast of
the Mississippi Valley Saturday through Saturday night.  This may
include one embedded short wave perturbation digging across the 
Texas Gulf coast, before coming in phase with amplifying short wave
troughing in a branch of westerlies emanating from the subtropical
eastern Pacific, across the northwestern into central Gulf of
Mexico.

Surface cyclogenesis may already be underway along a remnant frontal
zone across the south central Gulf of Mexico at the outset of the
period, associated with a preceding subtropical perturbation. 
Substantive further deepening of this cyclone appears probable, but
notable differences in its evolution remain apparent within the
various model output, particularly as it approaches and crosses the
central through northeastern Florida vicinity during the evening and
overnight hours.

...Florida Peninsula...
Given the model spread concerning the cyclone evolution, coupled
with initially dry and stable boundary-layer conditions across much
of the peninsula early Saturday and potential increasing inhibition
associated with pronounced mid/upper warming Saturday into Saturday
night, the risk for severe weather still appears largely conditional
at this point.  However, destabilization associated with rapid
low-level moistening within the inland spreading warm sector,
coincident with strengthening deep-layer shear and enlarging,
clockwise-curved low-level hodographs, could become sufficient for
organized convection, including supercells, with potential to
produce tornadoes and damaging wind gusts.  

Given this concern, slight risk probabilities will be maintained,
and extended southward through the remainder of the peninsula and
Florida Keys.  However, highest severe probabilities may ultimately
become focused near and just inland of coastal areas between Tampa
and Fort Myers Saturday evening, and near/offshore east central and
southeast coastal areas overnight, where low-level forcing and
destabilization will be most favorable.

..Kerr.. 12/15/2023

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