Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Sep 26 2024
Valid 261200Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR COASTAL
AREAS OF NORTHEAST FLORIDA...GEORGIA...AND SOUTH CAROLINA...
...SUMMARY...
Several tornadoes will be possible later today into tonight, in
association with Hurricane Helene. The greatest threat is expected
from parts of Florida into southeast Georgia, the Midlands and Low
Country of South Carolina, and southern North Carolina.
...FL/GA into the Carolinas...
Hurricane Helene is forecast to move north to north-northeast and
accelerate across the eastern Gulf of Mexico today, with landfall
expected in the Florida Big Bend region this evening. See NHC
forecasts and advisories for more information. Increasing low-level
flow/shear associated with Helene's large wind field will overspread
the Florida Peninsula this morning, southeast Georgia and parts of
SC by this afternoon, and eventually into parts of NC later tonight.
Low-level hodographs will become quite large, with 0-1 km SRH
increasing into at least the 250-500 m2/s2 range. This will support
tornado potential with any low-topped supercells that are able to
develop and persist within Helene's rain bands.
Due to Helene's large size and fast forward speed, a broad region
from Florida and Georgia northward into the Carolinas will see some
risk for tornadoes. During the day, Helene's rain bands will
overspread the FL Peninsula, with other outer bands potentially
moving inland across parts of GA/SC and eventually NC through
tonight. The Enhanced Risk has been maintained and expanded somewhat
from extreme northeast FL into coastal GA/SC, where multiple
low-topped supercells will be possible within an increasingly
favorable environment. Some tornado potential will spread into parts
of NC later tonight, with the northern extent of the primary tornado
threat still somewhat uncertain and dependent on Helene's forward
speed and track.
...Hudson Valley vicinity into southern New England...
An upper low will move eastward across southern Quebec and adjacent
portions of New England today. Strong large-scale ascent will aid in
the development of convection during the afternoon from southern New
England into the Hudson Valley. Lapse rates will be weak and
buoyancy modest at best, but enhanced mid-level flow through the
base of the upper low will support moderate to strong deep-layer
vertical shear. Consequently, a few stronger storms capable of gusty
winds are possible, but confidence in sufficient destabilization is
too low for severe probabilities at this time.
..Dean.. 09/26/2024
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