Tropical Weather Discussion
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301
AXNT20 KNHC 160557
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1256 AM EST Thu Nov 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURE...

A complex and elongated area of low pressure that is in the
western Atlantic Ocean will organize into an extratropical storm
system as it moves northeastward, into the central Atlantic Ocean,
during the next 24 hours. The main low pressure center of 1006 mb
is near 31N57W. A frontal trough extends from the 1006 mb low
pressure center, to a 1008 mb low pressure center that is
near 26N63W, and the trough continues to the SE Bahamas near
21N74W. A surface trough also is along 24N61W 21N65W. Upper level
SW wind flow is moving across the area of the frontal trough.
Precipitation: Widely scattered moderate to isolated strong
within 180 nm on either side of the line, from 19N67W off the NW
coast of Puerto Rico to 26N60W, beyond 32N55W. An upper level
ridge extends from N central coastal Puerto Rico to 24N53W, beyond
32N45W. The current forecast consists of: S-to-SW Gale-force
winds, and sea heights ranging from 10 feet to 13 feet, N OF 29N E
of the frontal trough to 52W. The gale-force winds will propagate
eastward ahead of the front through Thursday afternoon. Please
read the latest NWS High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...
The monsoon trough passes through Sierra Leone near 08N13W to
08N19W. The ITCZ continues from 08N19W to 08N26W to 05N40W, to the
coastal waters of French Guiana near 05N52W. Precipitation: widely
scattered moderate to isolated strong from 02N to 10N from 40W
eastward.

An upper level trough extends from a 32N24W cyclonic circulation
center to 24N25W 18N32W 13N42W and 05N50W. Precipitation: widely
scattered moderate to isolated strong from 10N to 12N between 30W
and 36W. Isolated moderate rainshowers from 03N to 15N between
40W and 60W.

...DISCUSSION...

...THE GULF OF MEXICO...

Upper level NW wind flow, dry air, and subsidence span the entire
area.

A surface ridge extends from a 1022 mb Georgia high pressure
center, into the central Gulf of Mexico. A surface trough is along
23N95W 22N92W 19N91W, in the SW corner of the Gulf of Mexico.
Rainshowers are possible from 20N to 24N between 88W and 94W.

...THE CARIBBEAN SEA...

A surface trough extends from a 1007 mb low pressure center that
is near 18N76W, off the eastern coast of Jamaica, to 12N80W. The
monsoon trough continues from 12N80W, across Costa Rica, into the
eastern Pacific Ocean. Precipitation: isolated to widely scattered
moderate and locally strong between 64W and 83W. scattered strong
in NW Venezuela, including Lake Maracaibo.

An upper level ridge extends from NW coastal Venezuela beyond the
NE corner of the Caribbean Sea. Broad upper level anticyclonic
wind flow spans nearly the entire Caribbean Sea. An upper level
trough is moving through the NW corner of the Caribbean Sea.

...HISPANIOLA...

Numerous rainshowers will persist across Hispaniola during the
next few days. Deep moisture is going to be pulled NE across the
area due to an upper level trough that is to the west of the
island. The precipitation amounts will be comparatively the
greatest in the afternoon and evening hours during maximum
heating. Localized flooding and life-threatening mud slides are
also possible during this time.

The GFS model for 250 mb shows that SW wind flow will move across
the area during the next 48 hours. The GFS model for 500 mb shows
that SW wind flow will move across the area during the next 48
hours. Hispaniola will be on the eastern side of a trough. The
GFS model for 700 mb shows that SW wind flow will move across the
area during day one. The trough that is just to the west of
Hispaniola during day one will move across Hispaniola during day
two.

...THE ATLANTIC OCEAN...

A middle level to upper level trough passes through Bermuda,
to 28N71W, across Cuba, into the NW corner of the Caribbean Sea
to the Gulf of Honduras. The trough is surrounded by comparatively
drier air in subsidence.

A surface trough passes through 32N22W to 29N23W and 27N26W.
Precipitation: isolated moderate from 28N northward between 20W
and 26W.

A surface ridge extends from a 1020 mb high pressure center is
near 29N40W, to 21N49W, to 16N60W.

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

$$
MT



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