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AGXX40 KNHC 280830

Marine Weather Discussion
NWS National Hurricane Center Miami FL
430 AM EDT Wed Jun 28 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


A weak stationary front continues across the NE Gulf coastal
waters this afternoon, and has moved little in past 24 hours.

Expect the boundary to drift S across the FL coastal waters
through this afternoon while gradually becoming diffuse.
Elsewhere gentle to moderate gentle E to SE winds prevail across
most of the basin. Mild seas prevail at 3-4 ft W half and 1-3 ft
E half. A low level trough has shifted NW across the W half of
basin past few days and has ignited active cnvtn across the NW
waters tonight but has recently diminished in coverage. The
trough is expected to drift slowly NW today and inland across S
TX and NE Mexico tonight.

Winds will veer slightly today with Sly return flow spreading
into TX and LA coasts tonight after trough moves inland. A
frontal system moving into the Great Plains will combine with
high pres moving to the Ern seaboard to produce moderate to fresh
return flow across most of the basin tonight and then gradually
strengthen to fresh to locally strong Thu night into Fri as the
frontal system moves SE into the TX Panhandle. Seas to increase
to 4-6 ft during this time, with Yucatan diurnal thermal trough
yielding strong winds across N and NW peninsula waters, with
potential to increase seas briefly to 7 ft. Somewhat similar
conditions to continue into the weekend as a weak high settles
into the far NE Gulf and the frontal boundary retreats Nwd into
the Central Plains.

55W AND 64W...

Modest Atlc ridge continues from central Atlc SW to just E of the
NW Bahamas and is yielding a modest pres gradient across the
basin this morning. A series of tropical waves moving W through
the basin are separated by SAL and fair weather in between. A
tropical wave is approaching Central America along 81W/82W, with
the best moisture behind the wave and producing widely sct cnvtn
invof of wave. Moderate E to SE winds and seas 4-7 ft are
occurring N of 13N and just behind wave axis. The next broad
tropical wave is moving across the Tropical N Atlc waters attm,
and has a secondary perturbation trailing invof 56W. Active
cnvtn continues with this wave and has lifted to along 15N with
and ahead of axis and will shift across the Windwards today.
A broad area of SAL and some zones of significant dust are moving
wwd across the E Carib to the W and NW of the wave and spread across
the top of this wave to just beyond 70W and E across much of the
MDR. ENE winds around 20 kt have accompanied this wave with E to
SE winds around 15 kt behind it. An area of 6-8 ft seas also
depicted by recent altimeter passes within the fresh ENE winds
and will shift W and hit the islands today. A slight SE shift of
Atlc ridge past 24 hours will tighten pres gradient slightly across
basin to yield peak nocturnal winds near 30 kt off of Colombia
early this morning and again tonight before gradient weakens as
second tropical wave moves across central portions and expands
fresh to strong winds across N central portions. Atlc ridge to
nose back into FL and NE Gulf of Mexico by the end of the week,
and behind this second wave, in order to bring a return to strong
trades across much of S central Carib on Friday and Saturday.


Atlc ridge extends from 1027 mb high near 37N47W to just E of
the NW Bahamas, while weak frontal boundary persists across N FL
and the extreme NW corner of FA. This is yielding moderate to
fresh E trades S of 23N E of 69W and moderate SE winds W of there
around the periphery of the ridge, becoming light to moderate S
to SW NE of the Bahamas. Seas are around 4 ft across the SE
waters in zone of trades and 2-3 ft elsewhere. The frontal
boundary will drift SE to along about 30N today before lifting N
of area tonight through Thu. This will maintain these generally
mild winds and seas across the waters through the end of the
week. As high pres shift E off mid Atlc coasts and into the W
Atlc tonight and Thu, the diurnal thermals along the N coastal
zone of Hispaniola will expand to 22N with seas pushing 8 ft
there during the evening.

Expect SAL and hazy conditions to prevail across the E and
central Carib and tropical N Atlc waters N of the tropical wave
moving into Windward Islands.


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


55W AND 64W...



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

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