• STRMDISC: TS Zeta 8

    From Weather Alert@21:1/175 to All on Mon Oct 26 18:37:00 2020
    044
    WTNT43 KNHC 261450
    TCDAT3

    Tropical Storm Zeta Discussion Number 8
    NWS National Hurricane Center Miami FL AL282020
    1000 AM CDT Mon Oct 26 2020

    After a significant strengthening episode early this morning, Zeta
    appears to have changed little in intensity recently. High spatial
    and temporal resolution GOES-16 visible satellite images indicate
    that the low-level center of the storm is located near the
    northwestern edge of the main area of vigorous deep convection. The
    current intensity estimate is held at 60 kt which is the average of
    recent Dvorak estimates from TAFB and SAB. An Air Force Reserve
    Hurricane Hunter aircraft is scheduled to investigate Zeta in a few
    hours, and should provide a better estimate of the strength of the
    storm.

    Zeta is moving northwestward, or about 305/9 kt. A mid-level high
    pressure area centered just east of Florida should steer the
    tropical cyclone on a continued northwestward heading for the next
    day or so, taking center over the northern part of the Yucatan
    Peninsula. By around 48 hours, Zeta is expected to turn northward
    over the Gulf along the western side of the high. Afterward, a
    shortwave trough moving into the southern Plains should induce a
    turn toward the north-northeast and take the center inland over the
    southern United States. The system should then move fairly quickly northeastward across the eastern U.S. and emerge into the Atlantic
    by day 4. The official track forecast has been adjusted a bit to
    the west of the previous one but not quite as far west as the
    corrected model consensus.

    Zeta is apparently experiencing some north-northwesterly shear given
    the displacement of the low-level center from the convection.
    However, this shear is expected to abate very soon, and the cyclone
    is likely to strengthen into a hurricane before reaching the
    northeastern Yucatan Peninsula. Some weakening should occur while
    Zeta interacts with land during the next 12 to 24 hours. The
    atmospheric and oceanic environment should be somewhat conducive
    while the system moves over the southern Gulf of Mexico in a day or
    two, and the official forecast shows some re-strengthening in 24-36
    hours. Later in the forecast period, when Zeta approaches the
    northern Gulf Coast, cooler shelf waters and some increase in
    southwesterly shear could cause some weakening. The official
    intensity forecast is similar to the previous ones and shows Zeta
    still near hurricane strength at landfall along the northern
    Gulf of Mexico coast, which is near or above most of the model
    guidance. Zeta is likely to become an extratropical cyclone when it
    emerges into the Atlantic, and be absorbed by a frontal system
    around the end of the forecast period.

    Given the timing of the track and the forecast wind radii, watches
    will likely be required for a portion of the northern Gulf Coast
    later today.

    KEY MESSAGES:

    1. Hurricane conditions and dangerous storm surge are expected in
    portions of the northern Yucatan Peninsula of Mexico tonight and
    early Tuesday. Tropical storm conditions could occur over extreme
    western Cuba beginning later today.

    2. Through Tuesday, heavy rainfall is expected from Zeta across the
    Yucatan Peninsula of Mexico, the Cayman Islands, and central to
    western Cuba. This rainfall may lead to flash flooding in urban
    areas. Between Tuesday night and Thursday, heavy rainfall is
    expected from portions of the central U.S. Gulf Coast into the
    southern Appalachians, and Mid-Atlantic States near and in advance
    of Zeta. This rainfall will lead to flash, urban, small stream, and
    minor river flooding.

    3. Zeta is forecast to be at or near hurricane strength when it
    approaches the northern Gulf Coast on Wednesday, and there is an
    increasing risk of dangerous storm surge, wind, and rainfall
    impacts from Louisiana to the Florida Panhandle. Residents in these
    areas should monitor the progress of Zeta, as Hurricane and Storm
    Surge watches will likely be issued later today.

    FORECAST POSITIONS AND MAX WINDS

    INIT 26/1500Z 19.1N 85.3W 60 KT 70 MPH
    12H 27/0000Z 20.1N 86.7W 75 KT 85 MPH
    24H 27/1200Z 21.5N 88.8W 65 KT 75 MPH
    36H 28/0000Z 23.3N 90.8W 70 KT 80 MPH
    48H 28/1200Z 25.7N 91.8W 70 KT 80 MPH
    60H 29/0000Z 28.9N 90.7W 65 KT 75 MPH
    72H 29/1200Z 33.0N 87.0W 35 KT 40 MPH...INLAND
    96H 30/1200Z 40.0N 73.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
    120H 31/1200Z...DISSIPATED

    $$
    Forecaster Pasch
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