525
AGXX40 KNHC 201007
MIMATS

Marine Weather Discussion
NWS National Hurricane Center Miami FL
507 AM EST Fri Jan 20 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...

MODEL PREFERENCE: Global model consensus. Medium to High
confidence.

A squall line is located from the western Florida panhandle to
the north central Gulf with high pressure ridging extending from
the southeast Gulf to the west central Gulf. Latest satellite
derived winds and seas along with ship, buoy, and CMAN data
depict mainly moderate return southerly flow across the basin,
except locally strong winds in convection associated with the
squall line. Seas are in the 1-3 ft range over the southeast
Gulf, 4-6 ft over the north central and northeast Gulf, and 2-4
ft elsewhere. The squall line will gradually weaken through this
afternoon.

A strong cold front is forecast to push across the Gulf waters
during the upcoming weekend. The front will enter the
northwestern Gulf Saturday night, reaching from southeast
Louisiana to near Tampico Mexico by Sunday morning, and from the
Florida Big Bend to the Yucatan Peninsula by Sunday evening. A
band of showers and thunderstorms will likely accompany the
front. This front will bring a significant increase in winds and
seas across the Gulf waters. Strong to gale force winds are
possible behind the front Sunday through Monday across the
northern and central Gulf, possibly spilling into the southeast
Gulf. A large area of seas building up to 16-19 ft is expected
behind the front. Conditions will gradually improve from west to
east Monday night through Tuesday night as high pressure builds
in behind the front.

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

MODEL PREFERENCE: Global model consensus. High confidence.

High pressure prevails north of the forecast waters. Latest
satellite derived winds and seas along with ship, buoy, and CMAN
data depict fresh to strong winds just offshore of the northwest
coast of Colombia, moderate to fresh winds near the Gulf of
Honduras, and gentle to moderate winds elsewhere, including over
the tropical north Atlantic waters. Seas are in the 6-8 ft range
just offshore of the northwest coast of Colombia, 4-6 ft
elsewhere in the south central and southwest Caribbean as well
as over the tropical north Atlantic waters, and 2-4 ft
elsewhere.

The area of high pressure will weaken later this week, which
will bring a decrease in trades across the Caribbean.

During the upcoming weekend, southeast to south winds are
expected to increase across the western Caribbean and the
Yucatan Channel ahead of a cold front moving across the Gulf of
Mexico. This front is currently forecast to reach the Yucatan
Channel and the northwest Caribbean Sunday night, accompanied by
strong winds and building seas. The front will reach from the
Windward Passage to the eastern coast of Nicaragua Monday night,
with strong southwest winds expected near the Windward Passage
just ahead of the front. Over the tropical north Atlantic
waters, expect continued mainly gentle to moderate trade winds
and seas of 4-6 ft.

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

MODEL PREFERENCE: Global model consensus. High confidence.

A cold front has exited to the east of 65W with high pressure
located over the central Bahamas. A warm front extends from the
South Carolina coast into the area near 28N75W. Latest satellite
derived winds and seas along with ship, buoy, and CMAN data
depict moderate to fresh northwest winds over the northeast
waters, with moderate northwest to north winds elsewhere east of
70W in the wake of the cold front, and light and variable winds
west of 70W. Seas are in the 7-10 ft range over the northeast
waters, 4-7 ft over the remainder of the forecast waters east of
77W and outside the Bahamas, and 1-3 ft west of 77W and west of
the Bahamas.

High pressure will linger over the central Bahamas through
tonight before shifting east this weekend as a strong cold front
begins to approach western portions of the area. Southerly
winds will increase to 20-30 kt across the northwest part of the
forecast area on Sunday ahead of the cold front, increasing to
gale force Sunday night. The cold front will move off the
southeast coast of the United States late Sunday night, with
strong to gale force winds spreading eastward both ahead of and
behind the front. Seas will build to 15-18 ft across a large
portion of the forecast waters through early next week.

$$

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

.GULF OF MEXICO...
.GMZ011...NW GULF INCLUDING STETSON BANK...
GALE CONDITIONS POSSIBLE Sun into Sun night.
.GMZ013...N CENTRAL GULF INCLUDING FLOWER GARDEN BANKS MARINE
SANCTUARY...
GALE CONDITIONS POSSIBLE Sun into Mon.
.GMZ015...NE GULF N OF 25N E OF 87W...
GALE CONDITIONS POSSIBLE Sun into Mon.
.GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W...
GALE CONDITIONS POSSIBLE Sun into Sun night.
.GMZ019...CENTRAL GULF FROM 22N TO 26N BETWEEN 87W AND 94W...
GALE CONDITIONS POSSIBLE Sun into Sun night.

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

.SW N ATLANTIC INCLUDING THE BAHAMAS...
.AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W...
GALE CONDITIONS POSSIBLE Sun night into Mon night.
.AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W...
GALE CONDITIONS POSSIBLE Sun night into Mon night.
.AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W...
GALE CONDITIONS POSSIBLE Mon night.
.AMZ117...BAHAMAS INCLUDING CAY SAL BANK...
GALE CONDITIONS POSSIBLE Sun night into Mon night.
.AMZ119...ATLANTIC FROM 22N TO 27N E OF BAHAMAS TO 70W...
GALE CONDITIONS POSSIBLE Mon into Mon night.

$$

*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 Lewitsky. National Hurricane Center.