marine weather discussion
NWS TPC/National Hurricane Center Miami FL
145 am EST sun Nov 18 2008

Marine weather discussion for Gulf of Mexico...
Caribbean Sea and southwest north Atlc S of 31n W of 55w.

Radiofax schedule for graphical wind wave...surface forecast and
peak wave period charts has changed. For the Atlantic Basin this
includes 24...36...48 and 72 hour wind wave..24...48..72 hour
surface forecast and 48 and 72 hour peak wave period charts. For
additional information please refer to the fax schedule on the
NHC web site at http://www.NHC.NOAA.Gov/radiofax.Shtml

Gulf of Mexico...
latest surface analysis reveals weak high pres near the Texas
coast arcing ESE to along 26n through the East Gulf. The ridge
lies in the wake of a strong cold front...which swept through
the Gulf waters this weekend and which has now made significant
headway into the NW Caribbean and SW N Atlc. Behind the front
over the extreme se Gulf waters...mostly se of a line running
from 26n82w to 20n97w ...winds continue to blow from the N to NE
at speeds up to 20 kt and seas range from 4 to 7 ft...though
there is indication of up to 8 ft seas over the Yucatan Channel.
Elsewhere over the Gulf...winds have relaxed considerably and
range from N 10 to 15 kt over the NE waters with 3 to 5 ft seas
to N to NE 10 kt or less elsewhere W of 90w...with seas of 2 to
4 ft. The one exception is closer to the Texas coast near the
core of the surface ridge...where the winds is light and more
variable. Seas there are generally running 1 to 2 ft.

Although marine conditions have been calming down over the Gulf
since sun...the lull will not last much longer...at least not E
of 90w. A secondary cold front just now entering the far N
central and NE waters should surge S and E today...overtaking
all but the SW waters by this evening. With another round of
strong surface high pres following the front...N to NE winds
will again increase fairly dramatically...reaching speeds of 20
to 25 kt E of 90w. Some of the moderate to strong NE flow will
extend as far W as perhaps 92w...with the strongest winds
farther N and E. The effects will be much more subtle and not
too apparent over the remainder of the Gulf from Tue into Wed.
During this time...expect seas to rebuild to 6 to 10 ft E of 90w
by Tue night in N swell...with seas of up to 8 ft perhaps
reaching as far W as 91w. W of there...lighter NE to E flow
should keep the region largely unscathed...with seas 3 to 7 ft
during this next wind event.

Longer-term...the surface ridge behind the secondary cold front
should reach over anywhere from the N central to NE waters later
Wed into early Thu before shifting southward Thu. With pres
equalizing across the region...winds and seas should rapidly
diminish and subside beginning as soon as late Wed and into Thu.
In fact...the Thu afternoon...the wind pattern across the Gulf
should closely resemble the current pattern...except that the
winds over the se waters will be lighter than they are now. Seas
should range from 2 to 4 ft N of 25n except 1 to 2 ft near shore
and 4 to 6 ft S of 25n around that time. Thereafter...models
have come into better agreement on yet another shortwave trough
digging into the eastern conus.

This shortwave should deliver a third cold front into the
northern Gulf waters by Fri morning...which should clear all but
the far SW Gulf by early Sat. Although the winds following this
feature will not be as strong as either of the last two
events...there should at least be a brief burst of moderate to
occasionally strong N to NE flow...which will veer NE to E later
Fri and Sat. With the duration of the event likely shorter...
wave heights could build to 5 to 8 ft over the waters N of 22n
by early Sat morning...with NOAA wavewatch and ensemble guidance
indicating the best chance for 8 ft seas over the central Gulf
waters initially and then spreading S toward the Yucatan as well
by late Sat.

Caribbean and tropical N Atlc...
the main marine concern over the Caribbean waters is the
moderate to strong winds following the strong cold front...which
has pushed across the NW waters and is about to slip into the
western part of the SW zone. As of this writing...the front lies
from extreme se Cuba but north of the Windward Passage through
western Jamaica through at least central Nicaragua. Evidence of
the latter is supported by an earlier Quikscat pass which show
northerly flow of 20 kt as far S as 12n offshore the E coast of
Nicaragua. The same pass..combined with other data across the
region...still indicates a fairly broad area of N to NE 20 to 30
kt winds with seas of 6 to 10 ft in N swell. The winds have...
however...begun to decrease over the far NW waters and the
Yucatan Channel...though seas of up to 8 ft are still likely
there. Satellite pictures also show some convective activity...
which has ignited along the front from near Cabo Gracias a Dios
Nicaragua to near 18n80w.

Now that the shortwave...which deposited the front...has already
lifted out the front has essentially stall and may creep only
slightly to the se early today. However...another vigorous
shortwave trough digging into the eastern conus should introduce
a well-defined secondary boundary...which should surge through
the Gulf early today and attempt to catch up to the main front
late in the day. This should give the front the necessary
impetus to make progress farther se during the next day or two
...With the front likely extending from Haiti through southern
Nicaragua Tue evening...from the Mona Passage through central
Costa Rica Wed evening...and then through Puerto Rico and to
northern Panama by Thu evening. The injection of additional
cooler and drier air into the NW Caribbean should provide for
another round of significant wind W of the front later Tue into
Wed...with the wind maintaining speeds of 20 to 30 kt...including
the Windward Passage. Guidance also indicates 20 to 25 kt
straight northerly flow spilling southward along the E coast of
Nicaragua..with northerly swell from the NW Caribbean oozing
into that area late Tue or early Wed. At a maximum...guidance is
coming into good agreement that seas should peak between 8 and
13 ft W of the front...with seas even to 8 ft in the Windward
Passage.

Elsewhere E of the front...NE to E winds which have been blowing
20 to 25 kt in the vicinity of the eastern Caribbean and
tropical N Atlc have wound down considerably over the last 24
hours. Although there still are likely spotty 20 kt winds across
this area even now...their areal coverage has greatly diminished
as of late. Seas generally range from 4 to 7 ft across the
area...though it is likely that wave heights of up to 8 ft are
occurring somewhere. To be sure...NOAA buoy 42059 in the eastern
Caribbean has seas of 7 ft at 06z. Over the next few days...NE
to E trades of 10 to 15 kt should remain relatively steady E of
the front with seas subsiding to 3 to 6 ft area wide.

Longer-term...as the front slides farther se the remainder of
this week...winds and seas will diminish and subside from NW to
se. The centroid of highest seas should also move from the NW
Caribbean to around Jamaica...the Windward Passage...and the SW
Caribbean offshore Nicaragua by Thu and Fri. Also of interest...
models show strong cyclogenesis in the wrn Atlc...which should
cause significant NW to N swell to spread from the Carolinas and
mid-Atlantic se to Hispaniola eastward into the tropical N Atlc
later Thu and Fri. Expect seas of 9 to 13 ft as the swell
arrives. Finally...a third front sweeping through the Gulf Fri
should usher in high pres from the Gulf into the SW N
Atlc...which is a pattern that favors moderate to strong NE to E
flow across the entire Caribbean and to a lesser extent the
tropical N Atlc. With this in mind...mariners can expect NE to E
winds 20 to 30 kt this weekend...with seas of 6 to 10 ft or 7 to
11 ft in NE to E swell.

SW N Atlc...
latest surface map shows the strong cold front from this weekend
extending from 29n65w to extreme se Cuba...with the N part still
edging slowly se. Within roughly 300 nm NW of the front S of 26n
N to NE winds are still blowing up to 20 kt and seas are up to 8
ft E of the Bahamas. Elsewhere within 200 nm of the front the
winds are much weaker...but seas of up to 8 ft in NW to N swell
are still occurring. To the E of the front...E to se winds of 10
to 15 kt are the rule...except S to SW N of 25n. Seas range from
4 to 7 ft. Of more importance though is a secondary cold front
now pushing offshore the NE Florida coast...with NW winds of 15
to 20 kt behind it.

The secondary front should rush se today and eventually merge
with the main front by early Wed. Meanwhile...to the N...strong
cyclogenesis is forecast to occur in the western Atlc well E of
Cape Hatteras. This development should ensure a fairly large
fetch generation area offshore the U.S. East Coast...with NW to
N winds of 20 to 30 kt. With winds of this strength in addition
to the swell forming...wave heights are forecast to build to 10
to 15 ft W of the front and N and E of the Bahamas by early Wed
morning. The swell event should further mature Wed...with 10 to
20 ft seas engulfing most of the waters W of the front and E of
the Bahamas...with highest seas NE. The swell should also bleed
through the Bahamas and between Florida and the western Bahamas
...With wave heights of 7 to 11 ft possible...especially in the
Gulf Stream. The consolidated front should sweep through the
remainder of the area by late Wed...with NW swell accompanying
it all the way down to the se Bahamas and from Hispaniola
through Puerto Rico Wed and Fri.

Longer-term...although winds should begin diminishing later Thu
and into Fri...significant NW to N swell should continue to
dominate the eastern half of area...with wave heights of 9 to 13
ft even into early Fri. Meanwhile...models have come into better
agreement on a third cold front reaching the far NW waters late
Fri and pushing across the northern half of the area into Sat.
Yet another batch of moderate to strong northerly flow is
forecast behind this feature...which should result in seas
rebuilding to 7 to 11 ft or 8 to 12 ft N and E of the Bahamas
during this time.

Atlantic...
none.

Caribbean...
none.

Gulf of Mexico...
.None.

Forecaster kimberlain. Tropical Prediction Center.

Copyright © 2008 The Weather Underground, Inc.