[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102319
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Aug 11 2023

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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Gale Warning E of 35W: The pressure gradient between a 1024 mb
high pressure located north of the Madeira Islands and lower
pressures in NW Africa supports gale force winds, with severe
gusts in the water passages between the Canary Islands. Latest
scatterometer data confirmed the presence of these winds. Meteo-
France has a Gale Warning in effect until 11/0600 UTC. For more
details, refer to the Meteo-France High Seas Forecast listed on
their website https://wwmiws.wmo.int

...TROPICAL WAVES...

An eastern Atlantic tropical wave is located near 25W, south of
17N, and is moving westward at around 10 kt. Scattered moderate
convection is noted ahead of the wave axis from 06N to 09N between
25W and 28W.

A central Atlantic tropical wave is located near 40W, south of
17N, and is moving westward at around 10 kt. Scattered showers
are near the southern end of the wave axis.

A tropical is moving across the eastern Caribbean with axis along
68W south of 20N, moving W at 15 to 20 kt. The wave is helping
to induce numerous showers and thunderstorms over Hispaniola and
regional waters, as well as over western Venezuela.

A second tropical wave is moving across the central Caribbean.
Its axis is along 79W south of 21N, moving W at 10 kt. The wave
appears to enhance convection over eastern Cuba, Jamaica and the
Cayman Islands.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic near Dakar, Senegal and
continues SW then westward to 11N20W to 08N35W to 08N47W. The
ITCZ extends from 08N47W to 10N60W. Please refer to the Tropical
Waves section above for convection in the area.

GULF OF MEXICO...

A ridge dominates the Gulf waters producing gentle to moderate
winds with the exception of moderate to locally fresh E winds
just N of the Yucatan Peninsula. Seas are 3-4 ft W of 90W and 1-3
ft E of 90W. Scattered showers and thunderstorms are noted over
the NE Gulf and northern Florida while numerous showers with
embedded thunderstorms are occurring over central and south
Florida where a diffluent pattern aloft is noted.

For the forecast, surface ridging across the Gulf will support
gentle to moderate winds over most of the basin during the next
several days. Moderate to fresh winds will pulse over the western
Gulf with slight to moderate seas. A thermal trough will move
off the Yucatan Peninsula each night and produce fresh to strong
winds off NW Yucatan.

CARIBBEAN SEA...

Satellite derived wind data provide observations of moderate to
fresh winds over the NE and central Caribbean, in the Windward
Passage and in the Gulf of Honduras. Gentle to moderate winds
prevail elsewhere. Seas are 3-5 ft across the E and central
Caribbean and 2-4 ft over the NW Caribbean. Late this afternoon,
convection has flared up mainly over Hispaniola, eastern Cuba
and Jamaica due to the passage of a couple of tropical waves.

For the forecast, moderate to fresh winds will prevail in the central
and eastern Caribbean as a tropical wave moves across the area through
Fri, locally strong in the south-central portion. Light to gentle
winds can be expected for the western part of the basin. On Fri
night through Tue night, fresh to strong winds and moderate seas
will expand across the central Caribbean, while moderate to fresh
winds and moderate seas prevail elsewhere.

ATLANTIC OCEAN...

A ridge dominates most of the Atlantic forecast waters with a
1024 mb high pressure located N of the Madeira Islands near
37N15W, and a second and weaker high pressure center of 1019 mb
situated near 27N61W. A stationary front is between these high
pressure centers and extends from 31N40W to 26N52W. A few showers
are near the southern end of the frontal boundary. An upper-level
low over the SE Bahamas is generating scattered showers and
thunderstorms. Similar convective activity is NE of Hispaniola
affecting mainly the waters from 19N to 23N between 66W and 70W.
Saharan dust is noted over most of the tropical Atlantic
reaching the NE Caribbean based on the Saharan Air Layer tracking
product from CIMSS.

Moderate to locally fresh NE winds are evident over the Cabo Verde
Islands while gentle to moderate trades are noted over the remainder
of the tropical Atlantic. Light to gentle winds are associated with
the aforementioned ridge. Seas are 6-8 ft E of 22W, and 4 to 6 ft
elsewhere E of the Bahamas.

For the forecast W of 55W, the subtropical ridge axis will continue
to be situated near 28N through the weekend and into early next
week. The northern portion of a tropical wave is expected to move
across the southeastern waters through Fri. This will increase winds
fresh to locally strong with moderate seas across the region, including
the Bahamas. Moderate to fresh winds will resume on Sat. Winds will
pulse fresh to locally strong north of Hispaniola during the evenings
Sat through Tue.

$$
GR
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