[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Tue Jul 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
2315 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 22W from
02N to 17N. It is moving westward at 10-15 kt. Isolated showers
are ahead of this wave within 30 nm of 11N24W.

A central Atlantic tropical wave, with a very noticeable
signature on satellite imagery, has its axis extending from
20N51W to 05N55W. This wave is moving westward at about 20 kt.
Scattered moderate convection is seen from 14N to 17N between
49W-59W. Fresh to strong easterly trade winds and seas of 6-9 ft
are occurring in the vicinity of the tropical wave, mainly north
of 13N.

An eastern Caribbean Sea tropical wave has its axis along 69W
south of 19N. It is moving westward at around 15 kt. Scattered
showers and thunderstorms are east of the wave to 62W and from
12N to 15N.

A central Caribbean Sea tropical wave has its axis along 79W,
south of 21N. It is moving westward at 13 kt. This wave extends
from eastern Cuba to Panama. Isolated moderate convection is
present near the northern portion of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis reaches the Atlantic through the coast
of northern Senegal near 16N17W and extends south-southwestward
to 07N24W and to 07N29W, where it transitions to the ITCZ and
continues to 06N38W and northwestward to 15N50W. It resumes
at 14N54W to 11N61W. Aside from convection that is associated to
tropical waves, numerous moderate isolated strong convection is
occurring from 05N to 08N between 27W-32W and within 60 nm south
of the ITCZ between 32W-37W.

GULF OF MEXICO...

The combination of divergence aloft associated to broad
troughing with a surface cold front and pre-frontal that is just
inland the southern United States has resulted in the
development of scattered showers and thunderstorms north of 27N
and east of 91W. The remainder of the Gulf of Mexico is in the
southwestern periphery of the broad subtropical ridge positioned
over the central Atlantic. This pattern is suppressing the
development of deep convection, especially in the southeastern
part of the Gulf, where a batch of dry Saharan dust is noted.
Moderate to locally fresh anticyclonic winds are found in the NE
Gulf and Bay of Campeche, along with seas of 3-4 ft. Stronger
winds and higher seas may occur near the strongest convection.
Elsewhere, moderate or weaker winds and 1-3 ft prevail.

For the forecast, a ridge will continue to dominate the Gulf
waters while a trough will develop over the Yucatan Peninsula
each evening and move offshore. Under this weather pattern,
moderate to fresh winds will pulse north and west of the Yucatan
peninsula during the late afternoon and evening hours. Elsewhere,
gentle to moderate anticyclonic flow and slight seas will
prevail.

CARIBBEAN SEA...

The combination of low-level convergence and plenty of moisture
is supporting numerous moderate to isolated strong convection in
the southwestern Caribbean Sea, especially within 120 nm of the
coasts of Nicaragua, Costa Rica and Panama. The rest of the basin
is under a generally dry weather pattern that is suppressing the
development of showers and thunderstorms, with the exception
of the shower and thunderstorm activity that is east of the
tropical wave in the eastern part of the sea as described above.

The pressure gradient between the 1024 mb high pressure near the
Azores and lower pressure in NW South America sustain strong to
locally near gale-force easterly trade winds in the south-
central Caribbean. This was confirmed by the latest ASCAT data
pass over that part of the sea. These winds also support seas of
8-10 ft in the area described. Fresh to strong easterly trade
winds and seas of 5-8 ft are found in the north- central
Caribbean. Moderate to fresh easterly breezes are occurring in
the eastern Caribbean and Gulf of Honduras, along with seas of
3-6 ft. Elsewhere, moderate or weaker winds and 2-4 ft seas are
present.

For the forecast, fresh to strong winds and rough seas will
continue over the central Caribbean through the weekend as two
tropical waves moves across the region. Locally near gale force
winds are likely off Colombia. Fresh winds will reach strong
speeds at night in the Gulf of Honduras through Tue, and resume
Sat night. Moderate to fresh trade winds will prevail over the
eastern Caribbean and tropical Atlantic waters through Sat
night. One of the aforementioned tropical waves is forecast to
bring an increase in winds and seas across the waters E of the
Leeward Islands on Tue, and over the NE Caribbean on Wed. Fresh
to strong northeast winds are expected in the Windward Passage
ahead of the wave axis by Wed night.

ATLANTIC OCEAN...

The tropical Atlantic is dominated by an expansive subtropical
ridge positioned near the Azores. The basin is mostly devoid of
deep convection aside from isolated showers found north of the NW
Bahamas. The pressure gradient between the ridge and a frontal
system off the eastern United States is sustaining moderate to
fresh southwest winds north of 28N and west of 55W. Moderate
easterly trade winds are noted south of 24N and west of 55W. Seas
in the waters described are 4-7 ft. Elsewhere W of 55W, light to
gentle anticyclonic winds and seas of 3-5 ft prevail.

Satellite imagery reveals that another outbreak of Saharan dust
is occurring off the coast of Africa and will be propagating
westward over the next several days. Moderate to locally strong
northerly winds are present in the eastern Atlantic, especially
south of 29N and east of 35W. Seas over these waters are 5-8 ft.
Moderate or weaker winds and moderate seas are prevalent over the
remainder of the basin.

For the forecast W of 55W, a ridge will remain in place across
the SW N Atlantic while a weak frontal boundary emerges off
the southeastern United States, and shifts eastward across the
waters north of 30N through late Wed. The pressure gradient
between these two features will support moderate to fresh
southwest winds north of 27N through Tue. Developing low
pressure north of the forecast region could bring increasing
winds over the northeast waters Tue night into Wed. The northern
end of a tropical wave is forecast to impact the waters north of
the Leeward Islands and Puerto Rico on Wed, and north of
Hispaniola, including approaches to the Windward Passage by Wed
night. Light to gentle winds will persist elsewhere along the
ridge axis.

$$
Aguirre
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