Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 171643

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Mon May 17 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 1200 UTC surface analysis and satellite imagery through 
1600 UTC.



A strong pressure gradient between a 1026 mb Azores High near
33N27W and lower pressures over NW Africa will support developing
gale-force winds in the METEO-FRANCE forecast area, that is 
called AGADIR. The gale-force winds are forecast to start at 
17/1500 UTC, and end possibly at 18/0600 UTC. Seas are forecast 
to range from 9 to 12 feet. Please, refer to the Meteo-France 
High Seas Forecast: www.meteofrance.com/ previsions-meteo- 
marine/bulletin/grandlarge/metarea2 for more details.


The monsoon trough passes through the coastal plains of 
Guinea near 10N15W to 06N25W. The ITCZ continues from 06N25W to 
03N61 along the coast of NE Brazil. Scattered moderate and
isolated strong convection is noted south of 05N and east of 23W.
Widely scattered moderate convection is noted south of 03N and
west of 35W.


A surface ridge over the SE United States along with a trough over
N central Mexico is producing E to SE moderate to fresh winds
across the Gulf. Seas are 4 to 6 ft. Scattered moderate convection
is noted within 120 NM of the Louisiana and Mississippi coasts.

High pressure along the middle Atlantic coasts extending SW to 
the NE Gulf will remain generally stationary throughout the week. 
This will support moderate to fresh E to SE winds over the basin 
through Tue. Winds will increase to fresh to strong late Tue 
through Fri as low pressure deepens across the Southern Plains.


A 1027 mb Bermuda High centered near 38N70W along with a 1010 mb
Colombian Low near 10N76W is contributing to fresh to strong NE 
to E trades in the S central Caribbean and gentle to moderate E 
trades elsewhere. Seas are 5 to 7 ft over the S central Caribbean 
and 2 to 4 ft elsewhere. The tail end of a shear line extends 
across central Cuba to 21N83W and is causing scattered showers 
from 20N to 22N between 78W and 83W. Scattered moderate 
convection is noted south of 10N in the SW Caribbean.

The Bermuda High NE of the Caribbean Sea will shift eastward and 
weaken, diminishing winds and seas modestly through Wed. Trade 
winds will increase basin wide Wed night through Fri night as high
pressure builds across the western Atlantic. 


A cold front extends southwestward from a 1006 mb low at 32N53W 
to 25N60W, where it transitions to a stationary front to 24N67W, 
where it transitions to a shear line to central Cuba. Winds north 
of 28N behind the front are NW fresh to strong, while ahead of the
front are SW to W fresh to near gale. Seas in these winds are 8 
to 12 ft. Scattered moderate convection is noted within 60 NM of 
the front east of 60W, while scattered showers are occurring 
within 60 NM of the front/shear line west of 60W. A ridge extends 
southwestward from a 1026 mb Azores High at 33N27W to 22N65W. NE 
to E trades south of the ridge are moderate to fresh. Elsewhere 
winds across the tropical N Atlantic are light to moderate with 
seas of 4 to 7 ft.

For the forecast west of 65W, the weakening frontal boundary from
25N65W to the central Bahamas will drift SE and dissipate through
late Tue. Its remnants will drift N along 23N-24N. The pressure 
gradient between high pressure off of Hatteras and the frontal 
boundary will support an area of fresh to strong easterly winds N 
of 23N and W of 68W with seas to 11 ft E of the Bahamas late Tue 
through Fri.

For the forecast east of 65W, the strong to near gale winds 
associated with the cold front will lift north of the area by late
Tue. Swells of 8 to 10 ft will continue north of 27N east of 65W 
through Wed night. NE to E trades south of 20N will continue as 
moderate to fresh for the next several days.


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Page last modified: Monday, 17-May-2021 16:43:35 UTC