000
AXNT20 KNHC 181627
TWDAT
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1815 UTC Sat Oct 18 2025
Tropical Weather Discussion for North America, Central America
Gulf of America, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.
Based on 1200 UTC surface analysis and satellite imagery through
1600 UTC.
...SPECIAL FEATURES...
Atlantic Large Swell Event: Northerly swell generated from a
storm force low over the Atlantic waters north of the discussion
area will generate rough to very rough seas over the western
Atlantic through this weekend. Seas in excess of 12 ft and
greater, with period of 12-14 seconds will continue to spread
southeastward today, covering the waters north of 26N between 44W
and 70W by tonight. The swell will then start to subside over the
discussion waters allowing for seas to drop below 12 ft Sun
night. Seas with this swell will peak near 18 ft over the waters
north of about 30N between 50W and 65W today.
Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.
...TROPICAL WAVES...
A far eastern Atlantic tropical wave has its axis near 21W from
from 02N to 16N moving westward around 10 kt. Nearby convection is
discussed in the monsoon trough/ITCZ section below.
A central Atlantic tropical wave has its axis near 36W from 02N
to 10N, moving westward at 10 to 15 kt. No significant convection
is evident near this tropical wave.
An Atlantic tropical wave has its axis near 48W-49W from 04N to
18N, moving westward at 15 kt. A recent scatterometer satellite
pass indicated strong winds along a sharp surface trough along
the wave axis, mainly from 08N to 14N. Rough seas are likely
ongoing in this area as well. The wave is also producing a large
area of showers and thunderstorms from 10N to 14N between 46W and
52W. Invest AL98 has been opened to monitor this wave, and gradual
development of this system is possible during the next several
days while it moves generally westward at around 15-20 kt.
Regardless of development, this system is expected to bring heavy
rainfall and gusty winds to the Windward Islands late this
weekend, then move across the Caribbean Sea through much of next
week. The wave will also produce strong winds and gusty seas
across the tropical Atlantic waters this weekend and the Caribbean
next week.
An Atlantic tropical wave has its axis near 58W south of 16N. It
is moving westward near 15 kt. Scattered moderate to isolated
strong convection is noted from 10N to 13N between 56W and 62W.
...MONSOON TROUGH/ITCZ...
The monsoon trough enters the Atlantic near 14N16W and extends
southwestward to near 10N20W then on to 07N30W. Segments of the
ITCZ extend from 07N30W to 05N35W, and from 04N38W to 04N48W.
Scattered moderate convection is noted from 05N to 08N between
10W and 15W, and from 08N to 10N between 17W and 26W.
...GULF OF AMERICA...
A few showers and thunderstorms are active off the central
Louisiana coast, south of a coastal trough reaching from off
Morgan City, Louisiana to off Port Connor, Texas. 1020 mb high
pressure is centered over Carolina coast near Myrtle Beach, SC.
South of the high pressure, a plume of moderate E to SE winds
with 4 to 5 ft seas extends from the Straits of Florida to near
the mouth of the Mississippi River. Light to gentle breezes with 1
to 3 ft seas are noted elsewhere.
For the forecast, moderate S to SE winds and slight to moderate
seas will prevail over the Gulf of America later this afternoon as
the high pressure builds over the western Atlantic. Locally fresh
S to SE winds are expected to develop tonight east of 90W,
including through the Florida Straits. A cold front will move
into the northwestern Gulf Sun morning and move southeastward over
the basin through Mon. Moderate N to NE winds are expected north
of the cold front, and locally fresh winds will be possible north
of 27N into Mon morning. High pressure is slated to develop over
the basin in the wake of the front, leading to gentle to moderate
winds and slight seas over the Gulf early next week.
...CARIBBEAN SEA...
Convergent easterly flow and lingering moisture from an old trough
are supporting scattered showers and thunderstorms across the
northwest Caribbean this morning, mainly north of 18N. Convergent
trade wind flow is also supporting a few showers and thunderstorms
across the far southwest Caribbean between Panama and Nicaragua.
Farther east, an upper trough is supporting a few showers and
thunderstorms across the south-central Caribbean off northeast
Colombia and northwest Venezuela. Scattered showers and thunderstorms
are impacting Trinidad and Tobago, ahead of the approaching
tropical waves. Clusters of these thunderstorms are training in
lines from east to west, and could bring heavy rainfall to these
islands and the nearby coast of Venezuela. Earlier showers and
thunderstorms near Puerto Rico and the Virgin Islands along a
trough appear to have dissipated. Moderate SE winds and 2 to 4 ft
seas are noted over the eastern Caribbean, and gentle E to SE
breezes and 1 to 3 ft seas are noted elsewhere.
For the forecast, winds will freshen over the south-central
through eastern basin tonight through Sun as high pressure builds
over the western Atlantic. Locally strong winds will be possible
in the Gulf of Venezuela on Sun. A long period N swell will lead
to rough seas through the Atlantic passages and over the waters
east of the Lesser Antilles Sun into early next week. Looking
ahead, a tropical wave located in the central Atlantic will move
westward this weekend, entering the eastern Caribbean Sun night.
Fresh to strong winds and rough seas will accompany this wave as
it moves over the eastern and central Caribbean early next week.
This system has a low chance of tropical development within the
next 7 days.
...ATLANTIC OCEAN...
Please refer to the Special Features section for further details
on a large swell event that will impact some sections of the
north-central waters through the weekend, and details about the
tropical wave/Invest AL98W near 50W.
A cold front extends from 31N50W to southern Bahamas and Turks and
Caicos Islands, west of 1021 mb high pressure near 25N38W.
Scattered showers and thunderstorms are active within 150 nm east
of the front. Fresh to strong W to NW winds are west of the front
to 65W, north of 25N. Fresh to strong SW winds are also evident
within 240 nm east of the front, north of 25N. Seas are in excess
of 8 ft north of 23N between 40W and 75W. Outside of the area of
winds and seas associated with Invest AL98 described in the
Special Features section, moderate to fresh NE to E trade winds
and 5 to 7 ft seas are noted south of 20N, with gentle to moderate
breezes and 4 to 6 ft seas elsewhere.
For the forecast W of 55W, the front will progress northeastward
this weekend. Fresh to strong W to NW winds are expected in the
wake of the front north of 27N and east of 65W through Sun
morning. Widespread rough seas associated with this storm system
will continue north of 20N and east of 77W through tonight, with
rough seas expanding southeastward through the Greater Antilles
Atlantic Passages on Sun. Very rough seas in excess of 12 ft are
expected north of 25N and east of 72W into Sun afternoon. Rough
seas will slowly subside from west to east Sun into early next
week. Elsewhere, moderate to locally fresh E to NE winds will
occur over the Bahamas and through the Florida Straits through Sun
morning as high pressure builds over the western Atlantic this
weekend. Looking ahead, a series of cold fronts are slated to push
off the coast of the southeastern United States early next week,
leading to increasing N winds offshore of Florida.
$$
Christensen
