Tropical Weather Discussion
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AXNT20 KNHC 190003

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
803 PM EDT Fri May 18 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.


A central Atlantic tropical wave has an axis that extends from
12N48W to 00N50W, moving W at 10 to 15 kt. This wave appears as a
poleward surge in low-level moisture and troughing at 700 mb. This
wave however has been become somewhat ill defined over the past
24 hours. No significant convection is noted at this time.


The monsoon trough passes through the coastal sections of Guinea
near 10N13W to 04N30W. The ITCZ continues from 04N30W to 06N45W.
Besides the convection associated with the tropical wave,
scattered moderate and isolated strong convection is from 00N to 07N
between 04W and 23W.



An upper-level trough with axis along 87W is interacting with a
deep plume of tropical moisture to the east of the trough axis to
produce scattered to numerous showers and embedded thunderstorms
mainly east of 84W affecting the Florida peninsula, Florida
Straits, and the majority of Cuba. A weak ridge axis extends
across the remainder of the basin along 25N producing mainly
gentle to moderate winds.

A new surface trough will develop just east of South Florida this
weekend and move into the eastern Gulf by Sunday. The upper-level
trough over the eastern Gulf will remain for several days, and
will continue to be the focus for shower and thunderstorm activity
mainly over the far eastern Gulf, where deeper moisture and
better lift will prevail.


An upper-level trough extends over the Yucatan Channel and the
northwest Caribbean. Upper-level diffluence on the eastern side
of this trough is supporting scattered moderate convection
N of 16N between 73W and 87W, and south of 14N east of 76W. Broad
high pressure over the subtropical Atlantic continues to support
moderate to fresh tradewinds over the NW and E Caribbean, and
fresh to strong winds over the central Caribbean. Light winds are
occurring over the extreme SW Caribbean near the eastern Pacific
monsoon trough. Wave heights of 8 to 10 ft continue to occur over
the S central Caribbean as confirmed by an recent satellite
altimeter pass and current buoy data.

Over the next couple of days, the upper-level trough will remain
in place enhancing shower and thunderstorm activity over the
western Caribbean. The surface ridging pattern over the Atlantic
will persist, keeping a similar wind profile in place across the
basin into the upcoming weekend.


A diffluent flow aloft to the east of an upper-level trough
currently over the eastern Gulf of Mexico is supporting scattered
moderate convection across Florida, the Bahamas, and Atlantic
waters mainly west of 74W. To the east, a 1028 mb high is centered
over the central Atlantic near 33N55W. A 1030 mb high is also
over the central Atlantic near 34N37W. These centers anchor a very
broad ridge that spans the Atlantic waters east of Florida to the
northwest African coast. The pressure gradient between the
central Atlantic high and lower pressures in the Caribbean and
eastern Gulf of Mexico support fresh to locally strong easterly
winds along the northern coast of Hispaniola and eastern Cuba.
Moderate to fresh tradewinds are occurring across the central and
western Atlantic south of 27N. Gentle to moderate winds cover the
central Atlantic N of 27N. Moderate to occasionally fresh NE winds
are occurring over the eastern Atlantic.

The overall pattern will change little over the weekend, with
ongoing convection possible west of 75W and strong winds expected
to continue along the northern coast of Hispaniola, and at times
eastern Cuba.

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