NOAA Forecast

National Weather Service

National Hurricane Center - Tropical Weather Discussion (Atlantic)

  1. 000
    AXNT20 KNHC 211205

    Tropical Weather Discussion
    NWS National Hurricane Center Miami FL
    805 AM EDT Thu Jun 21 2018

    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 0600 UTC surface analysis and satellite imagery through
    1115 UTC.


    There are four tropical waves between the west coast of Africa
    and the Lesser Antilles.

    A tropical wave is along 24W from 03N-12N. The Hovmoller Diagram
    shows the westward propagation of the wave, that coincides with a
    modest surge of moistened air based on the TPW product. Convection
    is limited near the wave's axis.

    A tropical wave is along 33W/34W from 3N-11N, moving W at 20
    knots. This wave shows up well as a low amplitude moisture surge
    on the TPW animation. Scattered moderate convection is noted where
    the wave meets the ITCZ.

    A tropical wave is along 42W from 3N-11N, moving W at about 15
    knots. The wave is well depicted in the moisture product.
    Scattered moderate convection is noted on either side of the
    wave's axis from 6N-8N between 38W-45W.

    Another tropical wave is approaching the Lesser Antilles. Its axis
    is along 58W from 6N-17N, moving W at about 10 knots. The TPW
    animation shows a surge of moistened air near the wave's axis. A
    cluster of moderate convection is already affecting Trinidad and
    Tobago. Scattered moderate convection is seen near 13N58W, and
    near the southern end of the wave's axis, from 6N-8N between 55W-
    58W. Moisture associated with this feature will continue to
    affect the Windward Islands this morning. The wave will then move
    across the eastern Caribbean this afternoon through Fri night.
    The associated moisture is forecast by the GFS computer model to
    spread out reaching the Leeward Islands later today and tonight,
    and Puerto Rico on Fri.

    A tropical wave is moving across the Caribbean. Its axis is along
    70W, and extends from Hispaniola to western Venezuela. The wave,
    combined with an upper-level trough crossing eastern Cuba, is
    producing scattered showers and tstms across the Windward Passage
    and parts of Haiti. Lingering moisture from this tropical wave
    will continue to support showers and isolated thunderstorms across
    Hispaniola today. Moisture and instability related to this wave
    will also affect the Windward Passage and eastern Cuba later


    The monsoon trough passes through the coastal sections of Guinea
    near 10N13W to 06N21W. The ITCZ continues from 06N21W to 06N30W
    05N40W to 05N51W. Outside of the convection associated with the
    tropical waves, isolated moderate convection is from 3N-7N
    between 24W-35W. Scattered moderate convection is from 4N-7N
    between 50W-55W.



    An area of low pressure over southern Texas will continue to support
    strong gusty winds, widespread showers and scattered thunderstorms
    in Texas coastal waters, and over parts of NE Mexico, including
    coastal waters this morning. Winds and seas in the NW Gulf will
    diminish further today as the low weakens. A broad ridge across
    the SE Gulf will support light winds and seas less than 3 ft east
    of 88W through Tue.

    A surface trough will develop in the Yucatan Peninsula each
    afternoon, then move westward across the SW Gulf during the
    overnight hours, accompanied by fresh east to southeast winds.


    A tropical wave passing south of Hispaniola will move into the
    western Caribbean today. A tropical wave along 59W will reach the
    Lesser Antilles later this morning. Fresh to strong winds are
    expected in the Gulf of Honduras Fri night through Sun night.
    Trade winds across the south-central Caribbean will strengthen
    tonight, then expand in coverage across the basin this weekend as
    high pressure builds in the central Atlantic. Seas will build to
    10-11 ft in the central Caribbean Sat night through Mon night.


    An upper-level trough extends from a cyclonic circulation centered
    near 27N65W to eastern Cuba. Scattered showers and tstms are
    noted on the SE semicircle of the low affecting mainly the waters
    from 24N-29N between 60W and 70W. A diffluent pattern aloft
    between the aforementioned upper-level trough and an anticyclonic
    circulation located E of the Lesser Antilles is helping to induce
    this convective activity.

    High pressure over the east-central Atlantic near 34N33W will
    slowly shift westward through Sat night, then remain nearly
    stationary near 30N55W through Tue. The pressure gradient in the
    central Atlantic associated with this high will support fresh
    trade winds S of 23N west of 50W, and allow seas to build to 6-7
    ft in southern waters E of the Bahamas this weekend.

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