Atlantic Discussions
Basin Outlook & Discussion
ABNT20 KNHC 281708

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Wed Jul 28 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

Forecaster Cangialosi


AXNT20 KNHC 281031

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed Jul 28 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 
0930 UTC.


An Atlantic tropical wave is along 22W from 18N southward, moving
W near 15 kt. This wave has yet to exit the monsoonal circulation
off of W Africa. Numerous moderate to strong convection is seen 
from 07.5N to 12N between 27W and western Africa.

Another Atlantic tropical wave is along 39W-40W from 19N 
southward, moving W 15-20 kt. Satellite imagery suggest that this
wave is dominated by a broad area of Saharan air south of 26N to
09N extending as far west as 47W. Scattered moderate convection 
is seen from 03.5N to 07N between 30W and 43W.

A Caribbean tropical wave has been relocated to 77W from 13N 
southward across Colombia, moving W at 15-20 kt. Asociated 
scattered convection is occurring across N Colombia. Dry stable 
air is immediately behind this wave across the E Caribbean.

Another tropical wave in the west Caribbean is along 87W from the
Gulf of Honduras southward into the eastern Pacific, moving W 
near 10 kt. Enhanced by an elongated upper-level low just to the
NW of the wave, scattered moderate to strong convection is 
present from 11.5N to 15.5N between 81W and 84.5W, including
coastal sections of Honduras and Nicaragua.

A third W Caribbean tropical wave moving W at 5 kt is no longer
discernible and is assumed to have merged with the wave upstream 
along 87W.


A monsoon trough extends across the Gambia coast at 13N16W to 
07N39W. The ITCZ then continues from 07N39W to the coast of 
Suriname at 06N55W. Beyond convection described above associated 
with the tropical waves, Widely scattered moderate convection is 
seen from 05N to 12.5N between 50W and 59W.


A surface trough is over the W central Gulf from 27N90W to 22N93W.
An upper-level low is centered across the NW Gulf near 26N97W. 
This combination is triggering scattered moderate convection from
22.5N to 26.5N between 90W and the Texas-Mexico coast. Associated
divergent aloft continues to enhance a cluster of strong
convection that has moved off of the NW coast of the Yucatan
Peninsula near 23N90.5W. Otherwise, light to gentle winds near 
the W periphery of the Atlantic ridge prevail across the basin, 
with seas of 1 to 3 feet.

The surface trough will drift toward the NW Gulf and weaken 
through Thu evening, while convection in the vicinity gradually
diminishes. In its wake, the Atlantic high pressure will begin to
build westward into the Gulf waters Wed and Thu, with a ridge 
persisting along 27N into Sun. 


Convergent trade winds behind the tropical wave along 87W are 
producing scattered strong convection over the western basin, and
into coastal Honduras and Nicaragua. Refer to the Tropical Wave 
section above for more information on additional convection. Dry
stable low level air and generally fair weather prevails to the
east of this area. Gentle to moderate trades S of the Atlantic 
ridge dominate the entire Caribbean basin. Seas of 2 to 4 ft are 
present over the W basin, and 3 to 5 ft are found over the central
and E basin, except to 6 ft off the NW coast of Colombia.

Gentle to moderate trade winds are expected across the basin 
through Thu. The exception will be moderate to locally fresh winds
near the coast of Colombia, in the Gulf of Venezuela and Gulf of 
Honduras, and S coast of Hispaniola. Winds will begin to increase 
across the E and central Caribbean Wed night through Thu night, 
then persist through the weekend, as the Atlantic ridge builds 
westward in the wake of a trough moving westward across the Atlc 
waters north of the Greater Antilles. 


Refer to the Tropical Waves and Monsoon Trough/ITCZ sections above
for convection across the Atlantic Basin.

The Atlantic ridge extends WSW from a 1029 mb Azores high, across
Bermuda to north Florida. This ridge supports light to gentle 
winds and seas of 2 to 4 ft N of 23N between 40W and the Georgia-
Florida coast. Overnight satellite scatterometer and altimetry 
data reveal gentle to moderate trades and seas of 4 to 6 ft from 
10N to 23N between 34W and the Lesser Antilles. Dry and stable 
atmospheric conditions across this region are producing generally 
fair weather. Moderate to fresh trades and seas at 6 to 8 ft are 
evident near the Canaries Islands N of 19N between the NW African 
coast and 34W. Gentle to locally moderate SE trades and seas of 5 
to 7 ft prevail across the rest of the basin.

The Bermuda-Azores high extends a ridge along 27N-28N to NE 
Florida and will persist through Thu. An inverted trough located 
along 65W south of 23N will move quickly westward across the SE 
waters this morning, then continue north of the Greater Antilles 
and across the southern Bahamas through Thu. Stable conditions
will limit associated convection until reach the central Bahamas. 
Expect fresh to locally strong easterly winds from late afternoon
through the night just off the N of Hispaniola, including 
approaches to the Windward Passage, during most of the forecast 



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