• Ophelia Eyes Ireland




    Hurricane Ophelia Discussion Number 23
    NWS National Hurricane Center Miami FL AL172017
    500 PM AST Sat Oct 14 2017

    Ophelia continues to have an impressive appearance in satellite
    imagery. The eye has remained clear all afternoon, surrounded by a
    very symmetric ring of cold cloud tops. Since the cloud pattern has
    not changed significantly over the past few hours, the intensity has
    been held at 100 kt. Microwave imagery and scatterometer retrievals
    indicate that beneath the cold canopy, Ophelia's structure is
    beginning to deteriorate, at least slightly. A GMI overpass around
    1700 UTC indicated that the vortex is beginning to tilt toward the
    east with height, probably a result of increasing southwesterly
    shear associated with a large upper-level trough to the west.
    Furthermore, a pair of earlier ASCAT passes suggested that an
    approaching cold front is already infringing on the NW quadrant of
    the circulation, within about 80 n mi of Ophelia's eye. Given the
    close proximity of the cold front and upper-level trough,
    extratropical transition will likely begin within about 12 hours. A
    favorable baroclinic environment may allow the cyclone to deepen as
    the wind field increases in size, so only a slight decrease of the
    maximum wind is expected through 36 hours. After that time, the
    post-tropical cyclone will likely occlude and interact with land,
    causing a faster rate of weakening and resulting in the eventual
    dissipation of the surface circulation in about 96 hours.





    Ophelia continues to pick up forward speed and the initial motion
    estimate is now 055/24 kt. The hurricane remains embedded within
    the southwesterly flow ahead of the aforementioned mid-latitude
    trough, and this will keep Ophelia on a northeast or north-northeast
    heading through the next 72 hours. The track guidance remains in
    fairly good agreement, though it has shifted southward a little for
    the first 24 hours. The new NHC track forecast has been adjusted in
    that direction, and is close to the GFS/ECMWF consensus throughout
    the forecast period.

    Although the center of Ophelia is not forecast to reach Ireland or
    the UK until Monday, wind and rains will arrive well in advance of
    the cyclone center. Individuals in those locations should consult
    products from their local meteorological service for more
    information on local impacts.

    Tropical-storm-force winds are possible throughout the Azores
    after Ophelia passes to the south and east tonight as a cold front
    moves through the islands. Interests in the Azores should refer to
    products issued by the Azores Weather Forecast and Watch Center.

    KEY MESSAGES:

    1. Ophelia is expected to be a powerful extratropical cyclone with
    hurricane force winds Monday while it moves near Ireland and the
    United Kingdom. Direct impacts from wind and heavy rain in portions
    of these areas are likely, along with dangerous marine conditions.
    For more details on the magnitude, timing, and location of impacts
    from post-tropical Ophelia, residents in Ireland should refer to
    products issued by Met Eireann, and residents in the United Kingdom
    should refer to products issued by the Met Office.


    FORECAST POSITIONS AND MAX WINDS

    INIT 14/2100Z 35.9N 23.7W 100 KT 115 MPH
    12H 15/0600Z 38.0N 20.0W 95 KT 110 MPH
    24H 15/1800Z 42.8N 15.3W 85 KT 100 MPH
    36H 16/0600Z 48.8N 12.3W 75 KT 85 MPH...POST-TROP/EXTRATROP
    48H 16/1800Z 54.0N 9.3W 60 KT 70 MPH...POST-TROP/EXTRATROP
    72H 17/1800Z 59.5N 3.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
    96H 18/1800Z...DISSIPATED

    $$
    Forecaster Zelinsky