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Atlantic Tropical Weather Discussion

AXNT20 KNHC 211000

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Oct 21 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 0600 UTC surface analysis and satellite imagery through 
1000 UTC.


The axis of a tropical wave is near 40W south of 13N, moving 
westward around 15 kt. Scattered moderate convection is seen from
04N to 10N between 35W and 44W. 

The axis of a tropical wave is near 63W south of 18N, moving 
westward 10-15 kt. Isolated showers and thunderstorms are east of 
the wave axis south of 14N.

The axis of a tropical wave is near 71W south of 20N, moving 
westward at 10-15 kt. Scattered moderate convection is noted from 
16N to 18N between 70W and 73W. 


The monsoon trough extends off the coast of Africa from 14N17W to
07N25W. The ITCZ continues from 07N25W to 02N37W. It resumes at 
02N39W to 01S44W. Aside from convection noted in the tropical 
waves section above, scattered moderate convection is noted from 
00N to 11N between 30W and 35W. 


A surface trough extends over the far SW Gulf. High pressure 
prevails over the northern Gulf. Moderate to fresh winds are noted
over the SE Gulf, gentle to moderate winds over the SW Gulf, and 
light to gentle winds over the Gulf waters north of 25N.

For the forecast, ridge will dominate the Gulf waters during the
forecast period. Moderate to fresh easterly winds are expected
across the SE Gulf today. Gentle to moderate winds will prevail 


A weak pressure gradient prevails across the Caribbean waters. 
Moderate to fresh winds are over the eastern Caribbean and gentle 
to moderate winds prevail elsewhere. Seas are in the 3-5 ft range.

For the forecast, high pressure N of the area will support fresh 
to locally strong trades E of the Windward Islands into Sun night.
During this period, moderate to fresh winds are expected over the
south- central Caribbean, with winds reaching locally strong in 
the Venezuela basin. Gentle to moderate tradewinds will prevail 


High pressure of 1023 mb centered near 32N71W is presently 
controlling weather regime over the western part of the area. This
is supporting moderate to fresh winds south of 25N and west of
60W, and light to gentle winds north of 25N. Seas over this area
are in the 5-7 ft range south of 25N and west of 60W, and 3-5 ft
north of 25N and west of 60W. Farther east, a cold front enters
the forecast waters near 31N47W to 28N59W and then becomes
stationary to near 24N62W. Scattered moderate convection is within
90 nm of the front. East of the front, 1023 mb high pressure is
centered near 27N43W. Gentle to moderate winds prevail over the
remainder of the tropical and subtropical waters north of 20N and
east of 60W. Seas over this area are mainly in the 5-7 ft range.
Over the tropical waters south of 20N, fresh to strong winds
prevail west of 45W, with moderate to fresh winds east of 45W.
Seas are in the 5-8 ft range. 

The Cumbre Vieja volcano, on the island of La Palma in the 
Canary Islands, has been erupting since 19 September 2021. Ash 
emission is on-going. Moderate to high volcanic ash is expected 
in the vicinity of the volcano. Elsewhere, light volcanic ash 
concentration is drifting south. Marine and aviation interests 
should monitor this ongoing situation by reading the Volcanic Ash 
Advisory issued by Meteo-France at 
/la- palma/.

For the forecast west of 65W, high pressure will shift eastward 
across the W Atlantic along 31N- 32N through early Fri, producing 
moderate to fresh winds south of 25N. Surface troughing will then 
prevail over the area through early next week.