• Irma Marches Towards Florida: Jose Follows On Heels

    Hurricane Irma Discussion Number 34
    NWS National Hurricane Center Miami FL AL112017
    1100 AM AST Thu Sep 07 2017

    The eye on satellite continues to be quite distinct, and data from
    an Air Force reconnaissance plane indicate that the initial
    intensity is 150 kt. The central pressure remains near 921 mb.

    The environment along the future track of Irma is favorable for the
    hurricane to maintain most of its current intensity, although some
    fluctuations are likely due to eyewall replacement cycles which
    are difficult to predict. There are no obvious reasons why Irma
    will not remain a powerful hurricane for the next 3 days while
    approaching Florida. Thereafter, an increase in the wind shear could
    lead to gradual weakening, but Irma is expected to remain a
    major hurricane until landfall occurs.

    The best estimate of the initial motion is toward the west-northwest
    or 290 degrees at 14 kt. Irma is being steered by the flow around
    the south side of the subtropical ridge, but in 2 to 3 days, the
    hurricane will be located on the southwestern edge of the
    aforementioned ridge, and a turn to the northwest and north-
    northwest should then begin. There has been no change in the
    guidance which is still quite clustered and brings the core
    of Irma very near the southeast Florida coast in about 3 days.
    The NHC forecast, which is similar to the previous one, is very
    close to the multi-model consensus and the HFIP corrected consensus
    HCCA. The later has been performing very well during Irma.


    1. Irma is a potentially catastrophic category 5 hurricane and will
    continue to bring life-threatening wind, storm surge, and rainfall
    hazards to the northern coast of Hispaniola today. These hazards
    will spread across the Turks and Caicos tonight and the Bahamas
    tonight through Saturday.

    2. A hurricane watch is in effect for much of Cuba. Irma is likely
    to bring dangerous wind, storm surge, and rainfall to portions of
    these areas on Friday and Saturday.

    3. The threat of dangerous major hurricane impacts in Florida
    continues to increase. A hurricane watch has been issued for south
    Florida, the Florida Keys, Lake Okeechobee, and Florida Bay. This
    watch will likely be expanded northward later today. Residents in
    these areas should heed any advice given by local officials.

    4. A storm surge watch has also been issued for portions of south
    Florida and the Florida Keys. This means there is the possibility of
    life-threatening inundation from rising water moving inland from the
    coastline during the next 48 hours in these areas. The Potential
    Storm Surge Flooding Map depicts a reasonable worst-case scenario -
    the amount of inundation that has a 10 percent chance of being
    exceeded. Because the Flooding Map is based on inputs that extend
    through 72 hours, it best represents the flooding potential in the
    watch area.

    5. The chance of direct impacts is increasing in portions of
    Georgia, South Carolina, and North Carolina, but it is too early to
    specify the magnitude and location of the impacts.


    INIT 07/1500Z 20.4N 69.7W 150 KT 175 MPH
    12H 08/0000Z 21.1N 71.7W 145 KT 165 MPH
    24H 08/1200Z 21.9N 74.2W 140 KT 160 MPH
    36H 09/0000Z 22.5N 76.5W 135 KT 155 MPH
    48H 09/1200Z 23.1N 78.4W 135 KT 155 MPH
    72H 10/1200Z 25.5N 80.0W 125 KT 145 MPH
    96H 11/1200Z 30.1N 80.6W 105 KT 120 MPH
    120H 12/1200Z 35.0N 82.0W 50 KT 60 MPH...INLAND

    Forecaster Avila


    Hurricane Jose Discussion Number 9
    NWS National Hurricane Center Miami FL AL122017
    1100 AM AST Thu Sep 07 2017

    Jose is developing an eye. Convection remains very symmetric around
    the center, and a well-defined mid-level eye has been evident in
    microwave imagery throughout the morning. Outflow remains well
    established in all quadrants, despite the close proximity of Irma
    to the west, perhaps in part due to the small size of Jose. The
    initial intensity has been held at 80 kt, based on the latest Dvorak
    classifications from TAFB and SAB. However, the overall trend of
    intensification is not likely to have ended, and Jose is still
    forecast to become a major hurricane in about 24 h. After about 48
    h, most of the intensity guidance indicates that Jose will begin to
    weaken, but the extent of that weakening varies quite a bit, in
    part due to uncertainty surrounding how much the shear from a
    deep-layer trough to the north and Irma may affect Jose after it
    passes the Leeward Islands. The official forecast is still close to
    the HWRF for the first 36 h, and close to the intensity consensus,
    IVCN, after that.

    The initial motion remains 285/16 kt. Almost no change has been
    made to the first 36 h of the forecast, and the hurricane is still
    expected to continue west-northwestward, along the southern extent
    of the subtropical ridge. Beyond that time, the global models
    suggest that an approaching mid-latitude trough will cause the
    ridge to retreat, causing Jose to turn more toward the northwest,
    and eventually toward the north. Based on the lastest model runs,
    this turn may happen a little later than previously expected. Thus,
    the NHC official forecast has been nudged toward the west at days
    3-5, and is close to the multi-model consensus, TVCX.


    INIT 07/1500Z 14.9N 50.6W 80 KT 90 MPH
    12H 08/0000Z 15.4N 53.1W 90 KT 105 MPH
    24H 08/1200Z 16.0N 56.0W 100 KT 115 MPH
    36H 09/0000Z 16.6N 58.5W 105 KT 120 MPH
    48H 09/1200Z 17.5N 60.5W 100 KT 115 MPH
    72H 10/1200Z 20.3N 64.4W 85 KT 100 MPH
    96H 11/1200Z 24.0N 67.5W 75 KT 85 MPH
    120H 12/1200Z 27.0N 68.5W 65 KT 75 MPH

    Forecaster Zelinsky
    This article was originally published in forum thread: Battening Down For Irma started by Photoboy View original post