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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 160436
TWDAT 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sat Oct 16 2021

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, 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 0000 UTC surface analysis and satellite imagery through 
0425 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A 1004 mb low pressure system is located 
near 32N49W or between Bermuda and the Azores. A surface trough 
extends from the low pressure to 22N69W. Latest scatterometer 
satellite data show gale-force winds in a small area about 270 nm 
south of the center. A large area of fresh to locally strong winds
is also observed over the central Atlantic E of the trough axis, 
roughly N of 20N between 40W and 60W. Scattered moderate to 
isolated strong convection is present within 250 nm E of the 
trough axis, especially between 42W and 60W. This system is 
expected to move quickly to the NE and merge with a strong mid- 
latitude system over the N Atlantic. Seas up to 13 ft are expected
within the area of gales. The area of gales is expected to lift 
north of our area this afternoon.

Gulf of Mexico Gale Warning: A cold front is approaching the SE
Texas coast and will move into the NW Gulf of Mexico over the next
few hours with fresh to strong northerly winds following it. The 
front will reach south central Florida to western Bay of Campeche 
Sun morning with moderate to fresh N to NE winds across most of 
the Gulf. Gale-force N winds will briefly move across the Mexican
waters Sat afternoon through evening and are then expected to 
develop off of Veracruz early Sun through afternoon. Seas are 
forecast to build up to 15 ft with the strongest winds.

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
on both warnings.

...TROPICAL WAVES...

The axis of a tropical wave is along 31W, south of 19N and moving
W at about 15 kt. Scattered moderate convection is noted where the
wave interacts with the ITCZ from 02N to 10N and between 25W and 
37W. A stable environment N of 10N is suppressing the development 
of showers and thunderstorms. 

The axis of a tropical wave is along 46W, south of 19N and moving
W at 10-15 kt. Scattered moderate convection is seen where the 
wave interacts with the ITCZ from 02N to 13N and between 37W and 
52W. A stable environment N of 13N is suppressing the development 
of showers and thunderstorms. 

The axis of a tropical wave is along 67W, south of 20N and moving
W at about 15 kt. No deep convection is observed near the wave 
axis. 

The axis of a tropical wave is along 80W, south of 19N and moving
W at 10-15 kt. A few showers are present near the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near 
12N16W to 07N23W. The ITCZ continues from 07N23W to 04N31W, then
west of a tropical wave from 04N32W to 05N45W, and then west of
another tropical wave from 06N48W to 09N60W. Aside from the
convection mentioned in the Tropical Waves section, no other
convection is observed on satellite imagery. 

GULF OF MEXICO...

Refer to the Special Features for information on the Gale Warning.

A cold front approaches the NW Gulf of Mexico and is expected to
move into the region in the next few hours. A line of showers and
thunderstorms is seen over southern Texas and NE Mexico and this
activity is likely to move over the offshore waters. Meanwhile, a
surface trough over Yucatan extends northward to 24N88W. A couple
of showers and isolated thunderstorms that developed over the
peninsula in the evening have moved into the E Bay of Campeche,
but this activity is expected to quickly wane over the next few
hours. The rest of the basin is dominated by a weak 1015 mb high 
pressure system positioned over the NE Gulf. The weak pressure
gradient results in moderate or weaker anticyclonic winds and 1-3
ft seas across the entire Gulf of Mexico.

For the forecast, a cold front will enter the NW Gulf tonight with
fresh to strong northerly winds following it. The front will
reach south central Florida to western Bay of Campeche Sun
morning with moderate to fresh N to NE winds across most of the
Gulf. Gale-force N winds will briefly move across the Mexican
waters Sat afternoon through evening and are then expected to
develop off of Veracruz early Sun through late afternoon.

CARIBBEAN SEA...

A couple of tropical waves are moving westward across the Caribbean
Sea. Please, see the Tropical Waves section for details. 

Divergence aloft provided by a sharp upper level trough that
drapes across the NW Caribbean Sea into Central America results in
widely scattered moderate to isolated convection across the NW 
and central Caribbean. The strongest convection is noted from the
coast of N Colombia to 17N and between 72W and 76W. Fairly
tranquil weather conditions prevail elsewhere in the basin. Recent
scatterometer satellite data show fresh to strong trades in the
south-central Caribbean, likely associated with the convection in
the area. Moderate or weaker trades are found in the rest of the
Caribbean. Seas of 3-4 ft are prevalent E of 75W and 1-2 ft
elsewhere.

For the forecast, a weak pressure gradient across the Caribbean 
basin will lead to tranquil marine conditions. A cold front will 
enter the NW Atlc over the weekend and move SE. High pres building
in the wake of the front will bring a return to moderate trade 
winds to the Caribbean Mon night.

ATLANTIC OCEAN...

Please refer to the Special Features section above for details on
the Gale Warning over the north-central tropical Atlantic.

Aside from the low pressure producing gale-force winds discussed
in the Special Features section, the rest of the tropical Atlantic
is dominated by a 1021 mb high pressure located near the Madeira
Islands that extends SW to the Lesser Antilles and provides for
fairly tranquil weather conditions. A weak surface trough extends
from 30N63W SW to 26N72W and NW to 28N78W near the NW Bahamas, but
no deep convection is noted with this system. Satellite-derived
wind data show fresh trades from 08N to 13N and between 33W and
47W. Another region of fresh to locally strong N-NE winds is found
E of 23W and from 15N to 27N, with the strongest winds noted near
the coast of Western Sahara. Moderate or weaker winds are present
in the rest of the basin. Seas of 4-7 ft prevail W of 60W, while
seas of 5-8 ft are noted S of 20N between Africa and the Lesser
Antilles. Seas of 4-7 ft are prevalent elsewhere.

The Cumbre Vieja volcano, on the island of La Palma in the 
Canary Islands, has been erupting since 19 September 2021. 
Low ash concentrations moving NW. Marine and aviation interests 
should monitor this ongoing situation by reading the Volcanic Ash 
Advisory issued by Meteo- France at http://vaac.meteo.fr/volcanoes
/la-palma/

For the forecast W of 65W, a cold front will move southeastward
off the SE U.S. coast and across Florida by the end of the 
weekend, reaching from Bermuda to the Florida Keys by Mon morning.
Expect fresh to strong N to NE winds behind the front through Mon
morning.

$$
DELGADO