Skip Navigation Links
NOAA NOAA United States Department of Commerce

Atlantic Tropical Weather Discussion

AXNT20 KNHC 150558

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Apr 15 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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0540 UTC.


Windward Islands Ashfall Advisory: An Ashfall Advisory has been 
issued, for La Soufriere
Volcano, that is on the island of St. Vincent, near 13.3N 61.2W. 
The volcano currently is in a state of unrest. It is possible 
that the volcano may erupt with little notice. It is possible 
that ash that was released earlier may be reaching the surface 
of the ocean, and low level visibility may be reduced. Mariners 
who are transiting the waters under the emitted ash advisory 
should exercise caution. Mariners who encounter volcanic ash or 
floating volcanic debris, are urged to report the observation to 
the National Hurricane Center, by calling 305-229-4424.


The monsoon trough passes through the coastal sections of 
Guinea-Bissau near 12N16W, to 05N20W. The ITCZ continues from 
05N20W, 02N23W, to 01N30W, to the Equator along 39W. 
Precipitation: scattered to numerous moderate to strong is from 
120 nm to 180 nm to the north of the ITCZ between 27W and 32W, 
and from 02N to 04N between 48W and 51W. Broken to overcast 
multilayered clouds, and isolated to widely scattered moderate, 
are from 05N to 16N between 44W and 60W. Isolated moderate to 
locally strong is elsewhere, from 10N southward from 50W 


A stationary front is in the coastal plains, from Louisiana to 
Texas. Precipitation: scattered to numerous moderate-to-strong 
is in parts of SE Louisiana, the coastal sections of 
Mississippi, and SW Alabama. Warming cloud top temperatures, and 
lingering but dissipating precipitation, cover the waters from 
27N northward. 

A cold front will reach the northern Gulf of Mexico on Thursday, 
then stall and weaken on Friday.
A stronger cold front will move into the NW Gulf of Mexico on 
Saturday, with strong northerly winds and building seas expected 
across the western Gulf of Mexico this weekend. The front will 
stall from central Florida to the Bay of Campeche on Monday 


The GFS model for 250 mb shows: broad anticyclonic wind flow in 
the Caribbean Sea. The GFS model for 500 mb shows: a trough 
along 64W; and anticyclonic wind flow from 16N northward from 
Jamaica westward. The GFS model for 700 mb shows: cyclonic wind 
flow from 15N southward from 70W westward; a ridge from 14N60W 
to 16N75W; anticyclonic wind flow from 15N northward from 75W 

A surface trough is along 11N73W in northern Colombia, to the 
Colombia/Panama border, beyond 07N80W, into the eastern Pacific 
Ocean. Precipitation: widely scattered moderate to isolated 
strong is in Colombia to the southeast of the surface trough. 
Scattered to numerous strong is in Costa Rica and southern 
Nicaragua from 09N to 12N. Numerous strong is in NW Venezuela, 
between Lake Maracaibo and the border with Colombia. Widely 
scattered to scattered moderate and isolated strong is from 12N 
southward from 78W westward.

Broken to overcast low level clouds, and isolated moderate 
rainshowers, cover the rest of the Caribbean Sea. The clouds and 
isolated moderate precipitation are moving with the 
surface-to-low level wind flow.

An Ashfall Advisory is in effect for La Soufriere Volcano on the 
island of St. Vincent near 13.3N 61.2W. Mariners who are 
transiting the nearby waters should exercise caution, and are
encouraged to report volcanic ash to the National Hurricane 
Center, by calling 305-229-4424. Moderate to fresh trade winds 
will prevail in the Caribbean Sea through Saturday. Fresh to 
SE winds are expected in the NW Caribbean Sea this weekend. 


The first cold front passes through 32N52W, to 25N60W, to 
21N70W, to the south of the SE Bahamas, to the coast of Cuba 
near 21N75W. Precipitation: isolated moderate rainshowers are 
within 120 nm to the east of the first cold front from 23N 
northward. A 1020 mb high pressure center is near 30N76W. 
Surface anticyclonic wind flow covers the Atlantic Ocean to the 
west and northwest of the first cold front.

A second cold front passes through 32N47W to 27N50W, 20N58W, and 
to 18N61W. Precipitation: widely scattered moderate to isolated 
strong is within 540 nm to the east of the cold front from 30N 
northward, and from 20N to 30N between 40W and the cold front 
from 20N to 30N. Isolated moderate is between 40W and the cold 
front from 17N to 20N.

A 1022 mb high pressure center is near 31N29W. Surface 
anticyclonic wind flow covers the Atlantic Ocean from 10N 
northward from the 32N47W 18N61W cold front eastward.

The current weakening cold front, that is to the northeast of 
the Leeward Islands, will move to the east of the area 
overnight. The trailing cold front, from 22N65W to just to the 
north of the Windward Passage, will stall and weaken through 
Thursday. Another cold front will move to the east of northern 
Florida into the northern waters by early Friday, then stall to 
the north of the Bahamas, from this weekend into early next