[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130515
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Jul 13 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
0430 UTC.

...SPECIAL FEATURE...

Gale

...TROPICAL WAVES...

A newly analyzed Atlantic tropical wave is near 23W from 13N
southward and moving W at 10 to 15 kt. Scattered showers and a few
thunderstorms are seen from 03N to 12N between 20W and 31W.

Another Atlantic tropical wave is along 4W from 12N southward and
moving W at 15 to 20 kt. Scattered moderate to isolated strong
convection is noted from 05N to 10N between 34W and 47W.

A much weaker Atlantic tropical wave previously located near 50W
has moved over French Guiana and Suriname. It has absorbed into a
near-equatorial trough and is no longer identifiable.

A Caribbean tropical wave is over central Cuba and southward to E
Panama, and moving W at 15 to 20 kt. Aided by upper-level
divergent winds, numerous showers and thunderstorms are occurring
over central Cuba, the Florida Strait and near the Panama-
Colombia border.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from near the Gambia/Guinea-Bissau
border at 12N15W to 08N28W to 08N42W. The ITCZ is seen farther W
from 08N46W to near the Suriname coast. Scattered moderate to
isolated strong convection is evident near the monsoon trough from
06N to 14N between the African coast and 20W, and near the ITCZ
from 06N to 10N between 48W and 53W. For additional convection
associated with the tropical waves, refer to the Tropical Waves
section above.

...GULF OF MEXICO...

Two broad upper-level lows, one is centered over the NW Gulf at
26N94W and another one near the Georgia-S Carolina border at
32N81W. Two modest surface troughs, one is across the N central
Gulf at 28N89W and another one over the SW Gulf at 22N9%W.
Interaction betweeen these surface and upper-level features is
triggering scattered showers and isolated thunderstorms SE of New
Orleans and over the Florida Panhandle, and over the SW Gulf just
N of the Bay of Campeche.

A surface ridge across the Gulf States will continue to support
gentle SE to S winds and seas of 1 to 3 ft over the N Gulf.
Gentle to moderate ENE to E trades and seas of 2 to 4 ft prevail
across the central and S Gulf. Locally fresh winds and seas up to
6 ft are seen over the Florida Strait associated with the
convection mentioned in the Tropical Waves section above.

For the forecast, a surface ridge just north of the area will
maintain gentle to moderate winds and slight to moderate seas
across much of the Gulf through Fri. A surface trough will develop
each day over the Yucatan and shift westward into the SW Gulf.
This will support fresh to occasionally strong winds off the
northwest Yucatan Peninsula and eastern Bay of Campeche during the
overnight hours through mid week.

...CARIBBEAN SEA...

Please refer to the section above for details on the tropical wave
moving across the basin.

Scatterometer data depicts fresh trades across most of the
eastern and central Caribbean, with locally strong winds in the
south-central Caribbean offshore of Colombia. Maximum seas are
estimated to be 10 ft in the south-central Caribbean, mainly off
the coast of Colombia, and 6 to 8 ft over the eastern Caribbean
where fresh tradewinds follow the tropical wave moving across the
basin. Moderate E to SE winds and 3 to 5 ft seas are noted over
the northwest Caribbean. In addition to the convection mentioned
in the Tropical Wave section, scattered moderate convection is
ongoing off Costa Rica and eastern Nicaragua west of 80W.

For the forecast, the tropical wave in the central Caribbean
will move west of the basin the middle of the week. High pressure
centered north of the region will support strong tradewinds and
building seas into Wed, including strong nocturnal NE winds across
the Windward Passage Tue night into Wed. Winds and seas will
diminish through Fri.

...ATLANTIC OCEAN...

Please see the Tropical Waves and Monsoon Trough/ITCZ sections
above for information on convection across the basin.

A surface ridge extends from the central Atlantic across Bermuda
to the central Florida coast. This pattern is supporting gentle to
moderate E to SE trade winds north of 25N west of 35W with 3 to 5
ft seas over open waters. Fresh trades are noted south of 25N
west of 35W to 60W with 6 to 9 ft seas. Fresh to locally strong
E winds are south of 25N and west of 60W over waters surrounding
the Greater Antilles with 4 to 6 ft seas. Divergence aloft
associated with an upper low now centered over the west Atlantic is
supporting scattered moderate convection mainly west of 75W. To
the east, another upper level low is centered near 28N53W and it
is reflected at the surface as a trough along 50W. Scattered
showers are noted along and west of the trough north of 25N
between 50W and 59W.

For the forecast, the surface ridge will lift north to along 32N
through Tue. Strong winds will continue to pulse off Hispaniola
and into the Windward Passage Tue night into Wed. Winds and seas
will diminish across the region through Fri as the area of high
pressure weakens.

$$
NATIONAL HURRICANE CENTER
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