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AGXX40 KNHC 100828 CCA
MIMATS

Marine Weather Discussion...corrected
NWS National Hurricane Center Miami FL
315 AM EST SAT DEC 10 2016

corrected Gulf of Mexico section

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...corrected

MODEL PREFERENCE: Global model consensus. High confidence then
medium confidence next week.

The 06Z surface analysis shows the former cold front as a
stationary front that extends from western Cuba southwest to
inland the northern Yucatan peninsula. Strong high pressure
present across the gulf is building eastward. The associated
ridge axis noses southward across eastern Mexico, and to
southeast Mexico. The resultant tight pressure gradient is
keeping gale force northwest winds of 30-40 kt in the far
southwest portion of the gulf within 60 nm in zone GMZ023 within
60 nm of Veracruz with large seas of 10-17 ft there. The 0340Z
Ascat pass highlighted a large swath of strong northeast winds
from 21N to 25N between 87W and 92W, while fresh northeast winds
were noted north of 25N. Recent altimeter data revealed quite
high seas of 9-14 ft within the area of strong northeast winds
and 8-10 ft within the area of fresh northeast winds between 88W
and 92W. Both buoys and the 0340Z Ascat pass show fresh to
strong northeast winds elsewhere, with the more concentrated
area of strong northeast winds south of 26N west of 92W. Seas
are in the range of 8-12 ft elsewhere south of 28N west of 85W,
and 4-6 ft remainder of area, except for 7-10 ft seas south of
25N east of 85W, including the entrance to the Yucatan channel
and Straits of Florida.

Water vapor imagery shows ample upper-level moisture streaming
eastward across much of the central and eastern gulf in broad
upper level southwest flow. Upper-level jet stream energy riding
along this flow is helping to trigger off scattered showers and
possible isolated thunderstorms over much of the eastern gulf
zones GMZ015 and GMZ021 as well as the southeast portion of zone
GMZ019. This activity will continue through Sunday evening.

The strong high pressure will continue to shift eastward and
weaken through early on Monday. The culprit tight pressure
gradient producing the gale force winds in the far southwest
gulf will slacken enough this afternoon to allow for the gale
winds to diminish to just below gale force. The seas in the
southwest gulf will lower to around 8-12 ft tonight, and to 6-8
ft on Sunday as the gradient slackens further. By Monday a
weaker gradient in place will allow for seas to lower to 3-4 ft
west of about 86W, and 2-3 ft east of 86W. By late Monday
night, seas are expected to be 2-3 ft throughout, except for 3-5
ft seas in the approach to the Yucatan channel, and in the
Yucatan channel.

Models are better agreement that a weak cold front will approach
the northern gulf on Wednesday, and move into the far northern
coast waters late Wednesday.

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

MODEL PREFERENCE: Global model consensus. High confidence.

The 0156 Ascat pass showed a swath of fresh northeast winds to
the south of Hispaniola and Jamaica, and also through the
windward passage where a ship is currently reporting similar
winds. A small pocket of strong northeast to east winds is along
the coast of Colombia. Seas remain in the 7 to 9 ft range over
the south central Caribbean. Both buoy and Ascat data show
moderate to fresh northeast to east winds elsewhere, with seas
in the 5-7 ft range, except for 3 to 4 ft west of 79W and higher
seas of 5-6 ft in the windward passage.

A well-defined surface trough, resembling an easterly wave, is
analyzed at 06Z along a position from just south of Haiti to the
northwest coast of Colombia. It is moving west at about 15 kt. A
tight gradient in the wake of the trough is helping to
contribute to the aforementioned fresh northeast winds over the
central Caribbean. Scattered showers and thunderstorms are
observed east of the trough to 65W. This activity is being
further enhanced by an upper level diffluent flow pattern
occurring to the east of an upper-level trough just to the west
of surface trough. The surface trough will reach near 77W/78W
tonight, near 79W Sunday night, and move over the western
Caribbean late Sunday night and Monday before it moves
inland Central America Monday night and Tuesday.

The cold front that moved across the Gulf of Mexico yesterday
has stalled across the Yucatan Channel and extends northeastward
over western Cuba. The front will slowly become diffuse through
Sunday as the strong high pressure behind it slides eastward.
The fresh northeast winds in the central Caribbean will become
mostly strong, and expand in coverage through Monday night, then
diminish on Tuesday. Strong northeast to east trades are
expected to materialize across the tropical north Atlantic zone
AMZ127 Sunday night through most of Tuesday. Seas are expected
to build to around 11 or 12 ft in the central Caribbean zone
AMZ031 Sunday through Monday before subsiding thereafter. Seas
are forecast to build to 8-10 ft in the tropical north Atlantic
zone Monday and Monday night before subsiding some on Tuesday.

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

MODEL PREFERENCE: Global model consensus. High confidence.

Strong high pressure is surging eastward from the Carolinas into
the western Atlantic behind a slow moving cold front currently
extending from near 31N64W to 28N70W to 26N76W where it becomes
stationary to the straits of Florida and to along northwest
Cuba. The front will move eastward and reach to roughly along
26N by this evening, while the stationary portion becomes
diffuse. The cold front portion will will then begin to
dissipate Sunday through late Sunday night. The strong high
pressure behind the front will then shift eastward to the
eastern part of the basin by Tuesday in response to a weak cold
front that approaches the southeast U.S. Strong northeast winds
south of the ridge, and to the north of the front will encompass
the area from 24N to 27N with seas in the 6-9 ft range through
the northern Bahamas by early this evening. As the high pressure
shifts eastward, these conditions will expand to much of the
area south of 28N through Sunday night, then shrink in coverage
through Tuesday as the pressure gradient slackens. Seas to 8 ft
will persist through Monday east of the Bahamas, then be
confined to zone AMZ127 on Tuesday as seas subside to 4-5 ft
elsewhere east of the Bahamas, and to 2-3 ft southwest of the
Bahamas. The previously mentioned cold front is expected to
brush the far northern waters Monday through Tuesday night.
Presently, model guidance highlights mainly fresh south to
southwest winds ahead of this front, and gentle to moderate west
to northwest winds behind it becoming light and variable Tuesday
night and Wednesday. Seas of 5-7 ft are expected east of the
front within the fresh to south to southwest winds, and 4-5 ft
behind the front.

$$

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

.GULF OF MEXICO...
.GMZ023...SW GULF S OF 22N W OF 94W...
Gale Warning through this afternoon.

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

.SW N ATLANTIC INCLUDING THE BAHAMAS...
None.

$$

*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.hurricanes.gov/marine

$$

.Forecaster Aguirre. National Hurricane Center.

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