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AGXX40 KNHC 301829

Marine Weather Discussion
NWS National Hurricane Center Miami FL
229 PM EDT Thu Mar 30 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


The pressure gradient associated with high pressure extending
from the SW N Atlc to the central gulf and low pressure in the
western basin associated with a cold front support moderate to
fresh winds E of 90W. SE winds are fresh to strong NW of the
Yucatan Peninsula to 24W and over the eastern Bay of Campeche
just to the east of a 1006 mb low located near 21N94W. The cold
front that extends from SW Louisiana to NE Mexico is preceded by
a squall line that extends from SE Louisiana to near 25N93W.
Lighting density data show strong convection and numerous tstms
along and in the vicinity of the squall line about N of 25N. The
cold front will quickly move to central waters this afternoon and
the eastern waters late tonight while it weakens. Fresh to
strong NW winds will be W of the front through tonight, then
mainly fresh southerly winds will precede the front across NE
waters. However, atmospheric instability associated with upper
level dynamics is expected to continue to bring numerous showers
and thunderstorms, some capable of producing strong gusty winds
and tough seas ahead of the front through Friday.

Another area of low pressure will develop over the southern
Plains Friday, and move over the southern United States during
the weekend. The pressure gradient between the low and Atlantic
high pressure ridging extending to the eastern waters will once
again increase the southeast winds to fresh to strong W of 85W. The
cold front associated with this second area of low pressure is
forecast to move off the Texas coast early Monday morning and
reach from west-central Florida to the northeast Yucatan
Peninsula at night. Mostly strong southerly winds are likely to
precede the front.


Generally, gentle to moderate trades dominate over the Caribbean
waters with the exception of SE of Hispaniola and the Gulf of
Honduras where fresh winds are noted. High pressure building
over the SW N Atlc will allow for the trades to become mainly fresh
at night while fresh to strong winds are forecast for the Gulf
of Honduras and along the coast of Colombia. This pattern of
moderate to fresh trades over the majority of the Caribbean and
fresh to strong winds over the Gulf of Honduras and Colombia
coast will persist through the upcoming weekend.

Over the tropical Atlantic waters, a weakening cold front
extends from 19N55W across the Leeward Islands to 15N65W and
sustains gentle to light easterly flow over just about the entire
Tropical North Atlantic zones, except for moderate trades in the
southeast portion of these zones. The front is forecast to
continue to move SE while gradually dissipating through tonight.
Northerly swell is decaying in the Tropical North Atlantic,
however wave model guidance is suggesting that quite an
impressive and extensive batch of long period northerly swell
will begin to infiltrate the Tropical North Atlantic waters
starting on Saturday. This northerly swell will propagate
through all of the Tropical North Atlantic zones into Monday
while inducing combined sea state of 8-11 ft.


A long-period northerly swell will move into the northeast
portion of zone AMZ115 beginning this tonight with seas of 6-9
ft. This swell will propagate through all of the eastern portion
of the basin into Sunday afternoon, with combined sea state
peaking to around 10 ft. Weak high pressure prevails over the
basin as a weak cold front extends across the northern waters
from near 28N65W to 27N73W then becoming stationary northwest to
30N79W. The front is followed by generally moderate northwest to
north winds. The cold front will move off the area late Friday,
while the stationary front becomes diffuse tonight. The next
cold front will emerge off the southeast U.S. coast on Friday
night and move over the north-central waters Saturday. A tight
gradient between the front and former high pressure in the area
will develop fresh to strong southerly winds over much of zone
AMZ113 on Saturady with seas of 8-9 ft. This strong southerly
flow will shift to the northeast zone Saturday night through
Sunday. High pressure in the wake of the front will slide
eastward to the northeast part of the forecast waters by late
Monday. A strengthening pressure gradient between a low pressure
system forecast to be over the SE CONUS on Monday afternoon and
the high pressure over the SW N Atlc will lead to a significant
increase of southerly flow over the northwest waters beyond
Monday night.


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


55W AND 64W...



*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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