Marine Interpretation Message
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318
AGXX40 KNHC 241808
MIMATS

Marine Weather Discussion
NWS National Hurricane Center Miami FL
208 PM EDT Sun Sep 24 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.

...GULF OF MEXICO...

A thermal trough will develop each evening over the NW Yucatan
Peninsula, move W-NW across the SW Gulf during the overnight
hours and dissipate over the SW Gulf waters by late each
morning. Expect the trough to be accompanied by a surge of
moderate to locally fresh winds that shift from NE to SE along
with brief seas to 4 ft through early Tuesday. Expect a tighter
pressure gradient on Tuesday evening with a fresh to locally
strong wind shift along the trough axis and seas possibly to 5
ft through early Wednesday. Elsewhere, weak high pressure will
continue to support gentle to locally moderate anticyclonic
flow, and 1-3 ft seas, through early Thursday. An upper-level
low is generating scattered showers and tstms across the N waters
mainly north of 27N E of 90W. Winds and seas could be higher
near tstms. In fact, a recent ASCAT pass showed some strong winds
in association with the tstms. The first cold front of the
autumn season is depicted by model guidance to move across the
northern and western Gulf waters on Thursday. Currently, it
appears that this front will be rather weak as it is expected to
be followed by mainly moderate NE winds and seas of 1-3 ft,
except for higher seas of 3-5 ft over the far western Gulf
waters.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...

The most recent scatterometer data indicate gentle to locally
moderate winds across the basin W of about 70W, and a little
tighter E of 70W with moderate to locally fresh E-SE winds. Seas
are rather low W of 70W where 1-3 ft seas are occurring, and 4-6
ft seas E of 70W. Similar seas are over the tropical N Atlantic
zones. Little changes are expected with the current observed
through much of Monday. The pressure gradient will then tighten
across the eastern and central Caribbean Sea and tropical N
Atlantic waters later on Monday and through Wednesday morning as
central Atlantic high pressure builds southwestward towards the
tropical N Atlantic waters and NE Caribbean Sea in the wake of
Hurricane Maria exiting the forecast waters of the SW N Atlantic.

Trades are forecast to increase to the 20-25 kt range along
with seas building seas to 8-9 ft over parts of the S central
Caribbean near the Colombia and Venezuela basins. These
increasing trades will spread some westward through late
Wednesday morning, and persist across parts of the central
Caribbean on Thursday. Winds are also expected to increase to
20-25 kt across the Gulf of Honduras during the evening hours
begining on Monday. Seas are forecast to build to 6-7 ft during
the period of strongest winds.

Long period northerly swell is expected to reach the waters E of
the Leeward Island on Tuesday, and E of the Windward Islands on
Wednesday, with building seas to 7-8 ft.

...SW N ATLANTIC INCLUDING THE BAHAMAS...

Hurricane Maria remains NE of the Bahamas, and it is located
about 260 nm ENE of Great Abaco Island, Bahamas at 24/1500 UTC,
with maximum sustained winds 90 kt with gusts to 110 kt, and a
minimum central pressure of 947 mb. Maria is moving N at 8 kt.
This general motion with some decrease in forward speed is
expected through Monday night. On the forecast track, the core of
Maria will be moving well east of the southeast coast of the
United States during the day or so. The latest NHC forecast
advisory has Maria exiting the forecast region by Monday evening.
Scatterometer data highlighted winds of 20-33 kt covering most
of the forecast waters N of 23N and NE of the Bahamas. Seas 12 ft
or greater are noted N of 24N between 66W- 80W. Buoy 41047
located at 27.5N71.5W is currently reporting S winds of 40 kt
along with seas of 29-30 ft. Maria continues to generate mixed
swell over just about the entire basin. Seas of 8 ft are noted
along the entrances to the Bahamas passages.

Swells generated by Maria are increasing along portions of the
southeastern United States coast and Bermuda and will be increasing
along the Mid-Atlantic coast later today. Swells also continue
to affect Puerto Rico, the Virgin Islands, the northern coast of
Hispaniola, the Turks and Caicos Islands, and the Bahamas. These
swells are likely to cause life-threatening surf and rip current
conditions. Otherwise, in the wake of Maria a surface trough will
extend from the N-central forecast waters SW to near the Central
Bahamas through Wednesday night then become diffuse Thursday as
central Atlantic high pressure builds westward across the eastern
portion of the area. Scattered showers and thunderstorms are
possible with the trough.

$$

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

.GULF OF MEXICO...
     None.

.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...
     None.

.SW N ATLANTIC INCLUDING THE BAHAMAS...
.AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W...
     Hurricane Warning today into Mon night.
     Tropical Storm Warning Tue.
.AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W...
     Tropical Storm Warning today into Mon.
.AMZ119...ATLANTIC FROM 22N TO 27N E OF BAHAMAS TO 70W...
     Tropical Storm Warning today.

$$

*For detailed zone descriptions, please visit:
http://www.nhc.noaa.gov/abouttafbprod.shtml#OWF

Note: gridded marine forecasts are available in the National
Digital Forecast Database (NDFD) at:
http://www.nhc.noaa.gov/marine/grids.php

For additional information, please visit:
http://www.nhc.noaa.gov/marine

$$

.Forecaster GR. National Hurricane Center.



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