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AGXX40 KNHC 290903

Marine Weather Discussion
NWS National Hurricane Center Miami FL
503 AM EDT Thu Jun 29 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


Weakening stationary boundary across the NE Gulf has shifted
barely inland across NE portions this morning. Mid to upper
trough digging SSE along the TX coast aiding in lift out ahead of
it across N central portions, where fresh SE winds per recent
scat pass providing moisture convergence. Look for that weather
to shift inland by afternoon as llvl troffing across the far NW
Gulf weakens and shifts NNW. Otherwise, no changes from recent
guidance trends. High pressure shifting ENE off mid Atlc coast
combining with frontal system across the Great Plains to produce
moderate to fresh return flow across all but NE part of basin
this morning and will gradually strengthen to fresh to locally
strong tonight into Fri as the frontal system moves SE into the
TX Panhandle. 4-5 ft seas across NW part W of 90W will increase
to 4-6 ft this afternoon, then focus of strong winds forecast to
shift a bit W and into far W and NW part, where 5-6 ft seas will
develop. Meanwhile, Yucatan diurnal thermal trough will yield
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 northwest into the Central
Plains. Winds will back to SE and focus highest winds and seas W

55W AND 64W...

Atlc ridge now settled across central Atlc with old stalled front
and pre frontal trough across Atlc waters N of basin, yielding
modest pres gradient across entire basin. Evening scat passes
showed fresh to strong trades across S central portions, and
across the Gulf of Honduras, while 20 kt winds depicted along NW
coast of Hispaniola spilling into Windward Passage. Seas
estimated 5-7 ft in Gulf of Honduras and 609 ft from offshore of
Colombia into SW Carib.

Two tropical waves affecting the basin this morning, one exiting
the basin and nearing 90W, and aiding in strong flow across Gulf
of Honduras, and second wave across central Carib along 70-71W.
This second wave has supported active convection past few days
and was accompanied by strong AEJ to 30-35 kt and definitive
narrow band of strong SAL just ahead of wave axis. These combined
for strong TSTM wind gusts reported yesterday morning across ST
Lucia. This wave also has had a secondary vort trailing behind by
about 5 deg that has lifted NW and currently forcing the line of
cnvtn extending NE across the NE Carib. Models have underforecast
the northern extend of this cnvtn and am trying to adjust and
account for it in this forecast. Appears that TUTT axis N of PR
and VI will provide sufficient evacuation for this approaching
line of moisture and convection for active diurnal convection
today and numerous coverage across the regional waters. Moderate
to fresh SE winds will build in behind this broad wave as it
shift W across the basin next few days. Broad nature of wave is
producing freshening ENE winds along and ahead of wave N of 15N
this morning as it moves across the NE Carib and will shift W and
brush along S coast of Hispaniola for enhanced Barahona winds
with building seas to 7-8 ft tonight into Fri. Atlc ridge will
build back into Bahamas Fri-Sat and establish broad area of fresh
to strong trades across entire central Carib Sat through Sun with
possible nocturnal max along Colombian coast to 30 kt Sat night-
Sun morning.

The next tropical wave across the central Atlc to reach the
tropical N Atlc waters late Fri and has significant negative tilt
yielding only moderate to fresh ENE trades with and ahead of
wave and modest seas 6-7 ft with passage of wave. Best moisture
and wx will occur along and behind this wave.


Atlc ridge has shifted into E central part of basin and extends
SW to about 60W where it is interrupted by deep layered
troffing. Lingering frontal boundary along 30-31N across NW
waters past few days looks to be finally drifting nwd attm as
llvl flow is veering ESE there. Portion of front N of 31N will
drag E today and continue to produce active wx across far NE
waters. Atlc ridge will then build modestly westward along 28-29N
Fri-Sat and support moderate to fresh trades S of 24N, except
for strong diurnal enhancement along N coastal waters of
Hispaniola late afternoon and evenings. Seas will remain 3 to 5
ft over open waters north of 22N, and 4 to 7 ft south of 22N.


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


55W AND 64W...



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Digital Forecast Database (NDFD) at:

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