SPC AC 241630

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1030 AM CST Thu Dec 24 2020

   Valid 241630Z - 251200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
   CAROLINAS AND SOUTHEAST VIRGINIA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   NORTHERN FLORIDA AND FAR SOUTHERN GEORGIA...

   ...SUMMARY...
   Severe thunderstorms are expected across portions of the Carolinas
   and Mid-Atlantic region this afternoon and tonight, with tornadoes
   and damaging wind gusts possible.

   ...Eastern/central Carolinas and Mid-Atlantic States...
   Multi-round severe convection is possible across parts of the region
   this afternoon into tonight, particularly for the eastern
   Carolinas/southeast Virginia, where semi-discrete warm sector storms
   this afternoon/early evening could be followed by a well-organized
   convective line late this evening and early in the overnight.

   Multi-layer cloud cover remains prevalent at midday across the
   region with air mass modification occurring near the coastal
   Carolinas where low/middle 60s F surface dewpoints are becoming more
   prevalent. North/northeastward-racing bands of convection over the
   eastern Carolinas will persist through the afternoon where the
   convection should gradually intensify as it becomes rooted within
   the increasingly moist/unstable boundary layer, although the
   persistent cloud cover and the possibility of a lingering warm layer
   aloft leads to some temporal uncertainty. Regardless, extremely
   strong low-level/deep-layer shear, accentuated by 55-60 kt in the
   lowest 1 km AGL and 300+ 0-1 km SRH, will be supportive of
   fast-moving supercells capable of a tornado/damaging wind risk,
   particularly late this afternoon through early evening. Given the
   magnitude of the vertical shear/SRH, a strong tornado cannot be
   ruled out.

   Otherwise, as previously mentioned, an additional round of regional
   severe risk will likely occur this evening into the overnight as a
   strongly forced convective line evolves and spreads
   east-northeastward across the Carolinas and coastal
   Mid-Atlantic/Delmarva. Damaging winds are the most probable severe
   hazard, although a QLCS-related tornado risk may exist as well.

   ...Florida/Georgia...
   A northeast/southwest-oriented composite convective line across
   southern Georgia/Florida Panhandle at late morning immediately
   precedes an eastward-moving cold front. Some additional
   moistening/diurnal destabilization will occur across the Florida
   Peninsula into far southern Georgia ahead of the front/convective
   line, with surface-based destabilization otherwise remaining minimal
   farther north into central/eastern Georgia. Low-level/deep-layer
   winds will further strengthen across the region, although low-level
   winds will tend to slowly veer with wind profiles trending more
   unidirectional over time. Even with relatively modest buoyancy, this
   scenario will support further organization and development of
   upscale-growing quasi-linear convective bands this afternoon. An
   isolated damaging wind/tornado risk will exist across the region
   through the afternoon, with the overall severe risk shifting
   eastward/tending to diminish toward and after sunset.

   ..Guyer/Lyons.. 12/24/2020

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