Tropical Weather Discussion
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000
AXNT20 KNHC 162345
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
745 PM EDT Mon Oct 16 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.

...SPECIAL FEATURES...

...Gale Warning...

As of 2100 UTC the frontal boundary that extends across the Gulf
of Mexico has become stationary, extending from 30N84W to 19N96W.
A tight pressure gradient and cool dry air associated with the
front is supporting northerly winds to continue to funnel along
the coast of Mexico reaching gale force from Tampico to Veracruz
through late today, with seas reaching 8 to 16 ft. The front will
gradually lose identity across the southeast Gulf of Mexico
through mid week and these conditions will subside.

...TROPICAL WAVES...

A tropical wave extending from 15N48W to 07N49W, moving west at
about 15-20 kt. There remains good continuity of this wave on
various satellite imagery. Scattered moderate convection is from
06N-13N between 42W-52W.

A tropical wave a little farther west, reaching from 14N56W to
06N57W, moving west at 10-15 kt. This wave is not as well
defined, with drier air is impinging on the northern extent of
it. No significant convection is observed with this wave at this
time.

A tropical wave is analyzed over the central Caribbean, from the
Windward Passage to the central coast of Colombia. There is good
continuity in various satellite data and satellite derived winds
showing a broad wave axis traversing the central Caribbean. No
significant convection is noted currently in the area of the
tropical wave axis, largely due to dry subsident air aloft moving
into the northwest and north central Caribbean at the base of an
upper-level trough north of the area.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the Senegal coast near 14N17W to
08N27W, where it transitions to the ITCZ and continues to 08N48W.
The wave resumes near 08N50W to 09N56W. Aside from the convection
related to the tropical wave along 49W, scattered showers are
noted south of the monsoon trough mainly east of 21W.

...DISCUSSION...

GULF OF MEXICO...

As of 2100 UTC, the frontal boundary that extends across the Gulf
of Mexico has become stationary, extending from 30N84W to 19N96W.
A Gale Warning is in effect for the area west of the front. See
the section above for details. Scattered moderate convection
prevails along and in the vicinity of the frontal boundary
covering most of the basin. Seas are building to 10 ft over the
northwest Gulf in the area of strong winds west of the front.
Gentle breezes and slight seas are noted elsewhere. High pressure
building north of the area in the wake of the front will allow
fresh to strong winds across the basin late in the week.

CARIBBEAN SEA...

The pressure gradient generated between the high pressure over
the central Atlantic and an approaching tropical wave east of
Barbados is supporting fresh to locally strong southeast winds are
noted over the eastern Caribbean. Showers and thunderstorms are
active from north of 14N and east of 69W affecting mostly Puerto
Rico and adjacent waters. Deep dry air is noted elsewhere,
related in part to dry subsident air aloft filtering over the
Caribbean on the south side of an upper-level trough northeast of
the Bahamas. Moderate winds and seas prevail currently. High
pressure building north of the area will allow strong winds to
pulse over the south central Caribbean mainly at night and in the
wake of passing short waves through mid week. This trend will
persist late in the week, with strong winds and building seas
forecast for across the eastern Caribbean.

...HISPANIOLA...

A negatively tilted upper-level trough is reaching from off the
Carolinas through the southern Bahamas and into central
Hispaniola. Divergence aloft is interacting with local sea
breezes enhancing convection over the island. This activity will
continue through the next 24 hours. A tropical wave moving across
Hispaniola mid week will bring additional potential for showers,
ending by late week as drier deep layer moisture moves into the
region.

ATLANTIC OCEAN...

Two tropical waves are moving across the basin. Refer to the
section above for details. A 1011 mb low is centered north of
Hispaniola near 24N71W. A surface trough extends north from the
low to 31N70W. Scattered moderate convection is north of 23N
between 64W-70W. A 1031 mb high is centered over the central
Atlantic near 35N43W, enhancing fresh trade winds in the deep
tropics. Elsewhere, the tail end of a weakening frontal boundary
is producing scattered showers over the Canary Islands and areas
of Saharan dust continue to move off northeastern Africa into
adjacent Atlantic waters as far west as 40W.

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

$$

ERA




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