Atlantic Tropical Weather Discussion

National Hurricane Center - Tropical Weather Discussion (Atlantic)

  1. 000
    AXNT20 KNHC 261758
    TWDAT

    Tropical Weather Discussion
    NWS National Hurricane Center Miami FL
    158 PM EDT Tue Sep 26 2017

    Tropical Weather Discussion for North America, Central America
    Gulf of Mexico, Caribbean Sea, northern sections of South
    America, and Atlantic Ocean to the African coast from the
    Equator to 32N. The following information is based on satellite
    imagery, weather observations, radar and meteorological analysis.

    Based on 1200 UTC surface analysis and satellite imagery through
    1630 UTC.

    ...SPECIAL FEATURES...

    Hurricane Maria is centered near 33.8N 73.1W at 26/1800 UTC or
    about 143 nm southeast of Cape Hatteras North Carolina, moving
    north at 6 kt. Minimum central pressure is 974 mb. Maximum
    sustained winds are 65 kt with gusts to 80 kt. Maria is a very
    large cyclone with hurricane-force winds extending outward up to
    90 nm from the center. Scattered moderate convection is within
    360 nm of this system in the eastern semicircle. Stable air on the
    western semicircle is resulting in mainly showers within 300 nm
    west of the center. Buoy data indicates seas of 15 ft extending
    over 150 nm south of the center, with 8 ft seas about 300 nm south
    of the center. See the latest NHC Forecast/Advisory under
    AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

    Hurricane Lee is centered near 29.9N 53.7W at 26/1500 UTC or
    about 585 nm east of Bermuda. Lee is moving to the west at 9 kt.
    Estimated minimum central pressure is 975 mb. Maximum sustained
    winds are 90 kt with gusts to 110 kt. Lee is a small cyclone with
    numerous moderate and isolated strong convection confined to
    within 75 nm of the center. Lee is forecast to remain a hurricane
    the next couple of days as it continues west today, then moving
    toward the west- northwest by Wednesday. See the latest NHC
    Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC
    for more details.

    ...TROPICAL WAVES...

    A tropical wave is exiting the coast of Africa with an axis
    extending from around 13N16W to 04N13W, moving westward at around
    15 to 20 kt. Scattered moderate convection is associated with a
    squall line within about 150 nm west of the wave axis, south of
    10N.

    A tropical wave extends along 40W from 20N to 06N, moving west at
    10 to 15 kt. This wave is well defined in 700 mb wind fields.
    However, aside from the southern portion of the wave, most of
    this wave is embedded within a fairly dry and stable environment
    per recent SSMI TPW imagery. Scattered moderate convection is
    south of 11N between 37W and 44W.

    A tropical wave is in the eastern Caribbean along 70W/72W, from
    20N to 08N, moving west at 10 to 15 kt. The wave is embedded
    within a weak 700 mb trough. Isolated moderate convection is
    within 90 nm of the wave axis north of 15N, and is partially due
    to upper level diffluence over the region.

    ...ITCZ/MONSOON TROUGH...

    The monsoon trough extends from the coast of Africa near 15N17W
    to 10N23W to 08N38W. The Intertropical Convergence Zone extends
    from 08N43W to 09N60W. Aside from convection associated with the
    tropical waves, scattered moderate to strong convection is from
    08N to 14N between 50W and 56W. Widely scattered moderate
    convection is within 90 nm of the monsoon trough between 22W and
    38W, and the ITCZ axis west of 56W.

    ...DISCUSSION...

    GULF OF MEXICO...

    A surface trough extends over the southwest Gulf from 23N95W to
    18N93W, and is void of deep convection. An upper low over the
    eastern Gulf supports scattered thunderstorms south of 28N, east
    of 89W. Weak ridging extends from Ohio Valley high pressure,
    southwestward over the northern Gulf, supporting gentle to
    moderate winds over the basin outside of thunderstorm activity.
    Over the next 24 hours thunderstorms will continue over the
    southeast Gulf.

    CARIBBEAN SEA...

    A tropical wave is over the E Caribbean. Please refer to the
    tropical waves section for details. A surface trough extends from
    21N82W to 13N83W and is located under a broad upper level
    anticyclone that is supportive of scattered moderate convection
    from 14N to 20N between 79W and 83W. Widely scattered
    thunderstorms are elsewhere north of 12N between 75W and 86W. A
    ridge of high pressure over the SW N Atlantic supports moderate to
    locally fresh trades over the Caribbean, except gentle winds over
    the southwest Caribbean near the E Pacific monsoon trough. Little
    change is expected over the next 24 hours.

    ...HISPANIOLA...

    A tropical wave is crossing the island today. However, dry air is
    limiting shower and thunderstorm activity to mainly isolated in
    coverage. Little change is expected through Wednesday.

    ATLANTIC OCEAN...

    Two tropical waves are moving across the basin. Please refer to
    the tropical waves section above for details. Hurricanes Maria
    in the western Atlantic and Lee in the central Atlantic are
    discussed in the special features section above. A plume of
    moisture is being pulled northeast across the bahamas and
    surrounding waters by an upper low over the eastern Gulf of
    Mexico. This plume combined with upper level diffluence from the
    upper low supports numerous showers and scattered thunderstorms
    from 22N to 28N, west of 74W. Low level convergence well to the
    southeast of Maria, combined with upper level diffluence from an
    upper low to the east is supporting scattered showers and
    thunderstorms N of 22N between 63W and 70W. Elsewhere, surface
    ridging prevails across much of the remainder of the central and
    the eastern Atlantic, anchored by a 1021 mb high centered near
    37N45W.

    For additional information please visit
    http://www.hurricanes.gov/marine

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