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AGXX40 KNHC 230735

Marine Weather Discussion
NWS National Hurricane Center Miami FL
235 AM EST Thu Nov 23 2017

Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea,
and Tropical North Atlantic from 07N to 19N between 55W and 64W
and the Southwest North Atlantic including the Bahamas


As of 0600 UTC, a 1012 mb low pressure system is located near
28N86W. A stationary front extends from the low across northern
Florida into the SW N Atlantic. A cold front also stretches from
the low SW across the eastern Bay of Campeche. A vigorous short-
wave trough rotating through a very well pronounced longwave
trough that enters the gulf across SE Louisiana, and extends to
near Tuxpan, Mexico supports these features. High pressure is
building southward over the western gulf behind the front cold
front with a 1027 mb center near Tmpico, Mexico. A very tight
pressure gradient between the high pressure and the cold front
has resulted in a large swath of strong to gale force northerly
winds overtaking the waters to the W of the cold front. The most
recent scatterometer data confirmed the presence of these winds.
In addition, an altimeter pass indicated seas of near 15 ft over
the western Bay of Campeche. Doppler Radar shows scattered
showers and thunderstorms over the NE gulf waters in association
with the low while similar convective activity is now approaching
SW Florida and the Florida Keys. Winds and seas could be higher
near tstms. The low pressure will move across northern Florida
today reaching the SW N Atlantic by this evening dragging the
associated cold front, forecast to cross the Yucatan Channel by
early Fri morning. Minimal gale force winds are expected to
persist over the SW gulf through early this morning, then winds
and seas will begin to gradually dimisnish across the gulf region
as the front exits the area. High pressure in the wake of the
front will dominate the gulf on Fri with gentle to moderate
northerly winds and seas of 3 to 5 ft. Southerly return flow will
briefly set-up over the western gulf on Sat, then a ridge will
build again across the gulf waters on Sun, producing mainly
gentle to moderate northerly winds and seas of 2 to 3 ft.

55W AND 64W...

A persistent surface trough is analyzed along 81W from 11N to
22N. Scattered showers and isolated thunderstorms are seen near
this feature. The trough is forecast to drift eastward over the
next couple of days as a cold front reaches the NW Caribbean.
Gentle to moderate trades and seas of 4 to 5 ft are noted E of
the trough axis over the east and central Caribbean while mainly
gentle northerly winds and seas of 2 to 3 ft prevail west of the
trough axis over the western Caribbean. The cold front, currently
moving across the Gulf of Mexico, is forecast to enter the NW
Caribbean by early Fri morning, reaching from western Cuba to
Belize by Fri evening, and from central Cuba to the Gulf of
Honduras on Sat evening while dissipating. The pressure gradient
between building high pressure over Central America and the
frontal boundary should bring an increase in northerly winds of
mostly 20 kt with possible pockets of 25 kt within about 120 nm
off the Nicaragua coast tonight through Monday night along with
max combined seas of 6 or 7 ft. There is a possibility that seas
may reach 8 ft on Monday as suggest by latest marine guidance.


A ridge is now confined to the extreme SE waters. A 1008 mb low
pressure is over the NE waters near 30N67W with a cold front
extending southwestward to the SE Bahamas. Latest satellite
imagery shows a large area of showers, with embedded tstms on
the SE semicircle of the low center. The most recent ASCAT pass
provided observations of minimal gale force winds within about
150 nm on the SE quadrant of the low, with a swath of fresh to
strong southerly winds covering the waters N of 23N between 63W
and 67W. An altimeter pass indicated seas up to 14 ft within the
area of gale force winds. These conditions will exit forecast
zone AMZ115 late this morning as the low pressure moves north of

Another low pressure system, currently over the eastern Gulf of
Mexico, will move across northern Florida today reaching the SW
N Atlantic by this evening. The associated cold front will move
across the western and central waters trough early Sunday morning,
and across the eastern and SE waters late Sunday through Monday
as it weakens to a frontal trough. Scattered showers and
thunderstorms with possible gusty winds are expected with both
the low and the cold front. Model guidance suggests that a
reinforcing cold front will reach the north waters by Sun evening
and move southward through Mon night, than stall near 27N on Tue.


.WARNINGS...Any changes impacting coastal NWS offices will be
coordinated through AWIPS II Collaboration Chat, or by

.GMZ023...SW GULF S OF 22N W OF 94W...
     Gale Warning early today.

55W AND 64W...

     Gale Warning early today.


*For detailed zone descriptions, please visit:

Note: gridded marine forecasts are available in the National
Digital Forecast Database (NDFD) at:

For additional information, please visit:


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