Tropical Weather Discussion
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AXNT20 KNHC 182345

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
745 PM EDT Wed Oct 18 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 1800 UTC surface analysis and satellite imagery through
2330 UTC.


A tropical wave is in the central Atlantic with axis extending
from 15N30W to 07N31W, moving west at 10 kt. The wave came off
the coast of Africa a couple of days ago as a very weak one.
Disorganized convection has augmented in the past few hours and
latest scatterometer data depicts fresh to strong winds associated
with it. Scattered moderate convection is from 10N- 15N between

A tropical wave is in the east Caribbean with axis extending from
17N63W to 07N63W, moving west at 15-20 kt within the last 24
hours. Shallow moisture in the area along with upper-level
diffluent flow support scattered showers and thunderstorms from
09N-16N between 59W-65W.

A tropical wave is in the east Caribbean with axis extending from
18N67W to inland Venezuela near 08N68W, moving west at 10-15 kt.
The wave is underneath an upper-level low that supports scattered
showers from 15N-18N between 66W-69W.

A tropical wave is moving across Central America with axis
extending from 15N83W to 05N83W, moving west at 10-15 kt. The
wave is in a region of abundant moisture at the lower levels.
This environment is supporting numerous showers and thunderstorms
from 04N-15N between 78W-85W.


The monsoon trough extends from the African coast near 08N13W to
07N19W. The Intertropical Convergence Zone extends from 07N19W to
09N26W, then resumes near 09N33W to 07N58W. Aside convection
associated with the tropical wave in the central Atlantic,
scattered moderate convection is from 06N-10N between 43W-58W.



A stationary front extends from the southern Florida near 25N81W
westward to 26N90W then curves southwest while weakening to
18N94W. The front is supported aloft by a mid to upper-level
trough progressing eastward over the eastern CONUS and west
Atlantic. Scattered moderate convection is within 240 nm south of
the boundary between 80W-94W. High pressure builds behind the
front supporting northerly fresh to strong winds in the western
half Bay of Campeche and in the northeast Gulf. The front is
expected to continue weakening tonight and gradually become
diffuse by early Thursday. Fresh to strong winds will prevail
through tonight and then decrease into moderate to occasional
fresh through the end of the week.


Three tropical waves are moving across the basin. Refer to the
section above for details. A mid to upper-level high covers the
western half of the basin proving stability and fair weather
across most of the basin except in the vicinity of the tropical
waves. Convection associated with these waves is forecast to
impact the Lesser Antilles, Puerto Rico and Hispaniola through
early Thursday. Moderate to fresh trades across the central and
eastern basin are expected to gradually increase through the end
of the week as high pressure north of the area strengthens.


Scattered showers and thunderstorms are observed over the southern
portion of the basin as a tropical wave approaches. This activity
will continue as the waves moves through.


A stationary front extends from 31N71W to the southern Florida
peninsula near 25N80W, which is expected to meander while
gradually dissipating through early Thursday. The front is
supported aloft by a mid to upper level trough. Scattered showers
are occurring within 75 nm on either side of the front. Farther
east, an upper level low support a surface trough from 30N48W to
26N48W. The remainder of the basin is under the influence of a
surface ridge anchored by a 1026 mb high centered near 32N35W.

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