• 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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