Atlantic Tropical Weather Discussion
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AXNT20 KNHC 181007
TWDAT 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1215 UTC Thu Dec 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 0600 UTC surface analysis and satellite imagery through 
0950 UTC.

...SPECIAL FEATURES...

Western and Central Atlantic Gale Warning: A stationary front
extends from 31N40W to 27.5N60.5W, where a 1014 mb low center has
formed, with the remnant frontal trough continuing through the SE
Bahamas. A 1026 mb Bermuda High is centered north of the area
along 69W. The pressure gradient between the high and these
features is producing fresh to strong NE to E winds, with strong
winds to around 30 kt occurring within 240 nm NW of the low
center. The low is expected to move slowly E-NE today, with gale 
force winds and rough to very rough seas are expected across the W
semicircle of the low center later this morning through Fri
morning, as the low deepens. Winds across the NW semicircle are
expected to increase to near 45 kt late this afternoon and 
evening, when seas will peak near 19 ft or 6.0 m. The low will 
then stall Fri and begin to gradually weaken before slowly 
exiting the forecast area to the north Sat morning. A large area 
of 12 ft seas in northeasterly swell will cover the area from 27N 
northward between 54W and 60W this evening through Fri morning 
before slowly diminishing. 

Please read the latest High Seas and Offshore Waters Forecasts 
issued by the National Hurricane Center at website: 
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and 
https://www.nhc.noaa.gov/marine/offshores.php for more information
this event.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic along the Liberia coast near
07N11W and then runs west-southwestward to 05.5N15W. The ITCZ 
continues from 05.5N15W to 04N37W to 01N48W. Convection near the
monsoon trough and ITCZ appears to also be influenced by an upper
level low near 16N34W, with a large area of scattered showers and
isolated thunderstorms occurring E of 35W between the Equator and
12N.

The eastern end of the East Pacific monsoon trough is triggering
widely scattered showers across the Caribbean waters near
Colombia.

...GULF OF AMERICA...

Derived satellite imagery shows patches of fog forming over
portions of the northern Gulf waters generally within 60 NM of the
coast. Mariners should be aware of the potential for reductions in
visibility. A surface trough is analyzed in the far W Gulf along
the Mexican coast, with another surface trough analyzed from the 
Yucatan Channel into the N central Gulf near 28N90W. Scattered 
showers and isolated thunderstorms are seen near both of these 
trough axes. Recent scatterometer data indicated fresh to strong 
E to SE winds and moderate seas of 4 to 7 ft across much of the 
Gulf east of 90W. Moderate or weaker winds and seas of 2-5 ft 
prevail W of 90W.

For the forecast, the pressure gradient between a ridge across 
the western Atlantic and a surface trough across the E central 
Gulf will produce fresh to strong S to SE winds today across the 
eastern Gulf that will shift northward into the Florida Big Bend 
late this afternoon and diminish. Otherwise, winds across the rest
of the basin will veer to the S and SW today ahead of the next 
cold front, which is forecast to move into the NW Gulf this 
evening. The front will then reach from the Florida Big Bend to 
near Brownsville, Texas by Fri morning, from SW Florida to NE 
Mexico Fri evening, then begin to lift northward and dissipate 
through Sat. High pressure will move into the NE Gulf Sat 
afternoon through Sun. 

...CARIBBEAN SEA...

The southern end of a surface trough is causing scattered showers
across the northwestern basin, including the Gulf of Honduras and
Yucatan Channel. Refer to the Monsoon Trough/ITCZ section for 
additional weather in the Caribbean Sea. Otherwise, a typical trade-
wind regime continues across much of the Caribbean Sea. Moderate 
to fresh trades and moderate seas prevail across much of the 
central and eastern Caribbean as well as off the south coast of 
Cuba, with areas offshore NW Colombia seeing fresh to strong NE 
winds and seas 7 to 8 ft. The remainder of the basin is seeing 
gentle to moderate or weaker winds and 3-6 ft seas.

For the forecast, fresh to locally strong trade winds and moderate to
locally rough seas will prevail over the south-central Caribbean
through Thu night as high pressure shifts eastward across the 
western Atlantic. Elsewhere, moderate to fresh winds are expected,
with the exception of gentle to moderate winds over the NW 
Caribbean. Large E swell will persist over the tropical Atlantic 
waters, through the Atlantic passages and into the eastern part of
the basin through Fri. High pressure will strengthen north of the
basin Thu into the weekend to bring a return to fresh to strong 
trades across the central and southwest Caribbean. 

...ATLANTIC OCEAN...

Please see the Special Features section about a Gale Warning in 
the western and central Atlantic.

A stationary front extends from 31N40W to 27.5N60.5W, where a 
1014 mb low center has formed, with the remnant frontal trough 
continuing through the SE Bahamas. A 1026 mb Bermuda High is 
centered north of the area along 69W. Scattered moderate isolated
strong convection is evident N of 26N between 50W and 60W. Refer 
to the Monsoon Trough/ITCZ section for additional convection in 
the Atlantic Basin.

Elsewhere across the Atlantic, a 1027 mb high is centered across
the eastern Atlantic near 29N26W, and extends a ridge across the 
basin to 60W. Accordingly, scatterometer data indicates fresh to 
strong trades and 7-11 ft seas across much of the tropical
Atlantic east of the Lesser Antilles. The exceptions are N of 25N
to the aforementioned frontal boundaries between 22W and 52W, 
withing the high pressure ridge, maintaining gentle to moderate 
winds and moderate seas. Moderate to fresh trades and moderate 
seas are also observed south of the frontal remnant trough in the 
vicinity of the southern Bahamas and the Greater Antilles. 

For the forecast W of 55W, low pressure of 1014 mb has developed 
near 27.5N60.5W with a weakening cold front extending 
southwestward through the SE Bahamas. A 1026 mb Bermuda High is 
north of the area along 69W and is producing fresh to strong NE to
E winds and rough seas north and northwest of the front and low. 
The low pressure is expected to become better organized and deepen
today as it moves slowly E-NE across the far NE zones. Gale-force
winds and very rough seas are expected across the W semicircle of
the low center later this morning through Fri morning, increasing
to strong gales this evening, before the low begins to slowly 
weaken and gradually exits the forecast area Sat morning. The next
cold front will move into the NW waters Fri afternoon, reach from
near Bermuda to the Straits of Florida Sat morning, then stall 
and weaken from 31N60W to the NW Bahamas Sat evening. Another cold
front may move into the NW waters Sun night. 

$$
Stripling