DAY1 ENHANCED RISK SE US
From
Mike Powell@618:250/1 to
All on Thu Sep 26 18:02:00 2024
ACUS01 KWNS 261936
SWODY1
SPC AC 261934
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 PM CDT Thu Sep 26 2024
Valid 262000Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
AREAS OF NORTHEAST FLORIDA...GEORGIA...SOUTH CAROLINA...AND FAR
SOUTHERN NORTH CAROLINA...
...SUMMARY...
Several tornadoes remain possible this afternoon into tonight across
the coastal Southeast in association with Hurricane Helene. The
greatest threat is expected across parts of Florida into southeast
Georgia, the Midlands and Low Country of South Carolina, and
southern North Carolina.
...20Z...
The Day 1 Convective Outlook remains on track. Multiple rainbands
with embedded low-topped, rotating storms continue to progress
across the FL Panhandle into central GA and SC. As the center of
Hurricane Helene approaches the FL coastline later this evening, the
vertical wind (and associated shear) profiles should increase
further across northern FL into the Carolinas. Large, curved
hodographs will support tornado potential with any embedded
supercell structures that can develop amid surface-based buoyancy.
The latest CAM guidance depicts an arc of low-topped supercells to
the northeast of Helene's center moving across central and eastern
SC between 06-12Z, when tornado potential will be maximized. If
enough surface-based buoyancy can advect inland, a strong tornado
could develop closer to the SC coastline.
..Squitieri.. 09/26/2024
.PREV DISCUSSION... /ISSUED 1127 AM CDT Thu Sep 26 2024/
...Florida/Georgia into the Carolinas...
Hurricane Helene is currently centered about 200 miles southwest of
SRQ. This system is characterized by a very broad/expansive wind
field, with the VAD profiles at JAX and CLX showing 50 and 35 kt at
2 km, respectively. Stronger low-level winds are already in place
across FL. Rotation has been noted in cells both off the central FL
Panhandle south of TLH as well as from coastal GA into the SC Low
Country.
The general trend of rotation within the deeper, more cellular
convection is expected to continue throughout the day into the
evening across the entire region, with some chance for an increased
frequency of rotating cells given the strengthening wind profiles.
Best overlap between modest buoyancy and veering low-level wind
profiles is still expected to occur from southeast GA northward into
coastal SC and far southern NC (i.e. ILM vicinity). For much of this
region, the higher dewpoints currently remain offshore, but
additional advection inland is anticipated as the system moves
northward. This additional low-level moisture should increase
buoyancy slightly, which is expected to result in a relatively
higher tornado threat. This relatively higher tornado risk is
expected from 04Z to 18Z Friday, which bridges the Day 1 and Day 2
periods. As such, additional information regarding the tornado risk
for this area can be found in the Day 2 Convective Outlook.
$$
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