[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241016
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Aug 24 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 1200 UTC surface analysis and satellite imagery through
1000 UTC.

...TROPICAL WAVES...

A tropical wave is along 24W/25W, from 20N southward, moving W at
10 to 15 knots. A 1009 mb low pressure is along the wave axis near
08N. The wave is producing a concentrated area of showers and
thunderstorms mainly from 06N-11N between 25W-30W. This convective
activity has become a bit better organized during the overnight
hours, and some additional development is possible over the next
several days while this system moves westward to west-northwestward
at 10 to 15 kt over the eastern tropical Atlantic. The latest
Tropical Weather Outlook states that this system has a medium
chance of tropical cyclone formation through 5 days.

A tropical wave is along 44W, from 21N southward. The wave is
moving W at 10 to 15 knots. A 1010 mb low pressure is analyzed
near the northern end of the wave axis. Fresh to strong winds are
noted per scatterometer data on the E side of the low center.
Scattered moderate convection is seen from 20N-23N between 42W-
45W. Little development is expected during the next day or two due
to marginally conducive ocean temperatures and strong upper-
level winds. Afterwards, environmental conditions are expected to
become more favorable for gradual development, and a tropical
depression could form by the end of the week while the system
moves northwestward to northward at 10 to 15 mph over the central
Atlantic. The latest Tropical Weather Outlook gives this system a
medium chance of tropical cyclone formation through 5 days.

A weak tropical wave is approaching the Lesser Antilles with axis
along 58W, from 19N southward. The wave is moving W 10 to 15 knots.
Convection is limited near the wave axis.

An active tropical wave is moving across the eastern Caribbean.
Its axis is along 69W and extends from Dominican Republic to
western Venezuela. The wave is producing scattered showers and
thunderstorms, particularly from 10N-15N between 61W-73W. This
convective activity is affecting the Windward Islands. The wave
is also helping to induce scattered moderate to strong convection
over western Venezuela. A broad area of low pressure is expected
to form along the wave axis over the southwestern Caribbean Sea
later this week. Thereafter, environmental conditions are forecast
to be favorable for gradual development, and a tropical depression
could form by the end of the week while the system moves west-
northwestward to northwestward over the northwestern Caribbean
Sea. This system has also a medium chance of tropical cyclone
formation through 5 days according to the latest Tropical Weather
Outlook.

A second tropical wave is over the Caribbean Sea along 86W from
20N southward, moving westward 10 to 15 knots. The wave axis
crosses northern Central America where is enhancing some shower
and thunderstorm activity.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean through the coastal
border sections of Mauritania and Senegal near 16N16W, then
crosses just to the south of the Cabo Verde Islands, and continues
westward to 14N30W to 13N40W to 08N46W. The ITCZ extends from
08N46W to 09N57W. Most of the convective activity across the
region is related to the tropical waves, with the exception of a
cluster of moderate convection near the Mauritania/Senegal border.

...GULF OF MEXICO...

High pressure remains in control of the weather pattern across the
Gulf waters producing mainly gentle to moderate winds. Seas are
generally below 4 ft. The northern end of a tropical wave, with
axis along 95W, is producing scattered showers and thunderstorms
over the Bay of Campeche. Fresh to locally strong winds are also
noted in that area. A surface trough is analyzed over the NE Gulf
extending from the Florida Panhandle to SE Louisiana. Scattered
showers and thunderstorms are also observed near the trough axis.

For the forecast, high pressure will dominate the basin through
Fri. Fresh winds will likely pulse west of the Yucatan Peninsula
tonight and again Wed night due to local effects induced by a
thermal trough. Increasing pressure gradient between high pressure
over the Gulf waters and a possible tropical system over the NW
Caribbean will result in fresh to strong easterly winds over the
SE and south-central Gulf during the upcoming weekend.

...CARIBBEAN SEA...

Two tropical waves are moving westward across the Caribbean Sea.
Please, see the Tropical Waves section for details.

The most recent scatterometer data provided observations of fresh
to strong winds across most of the east and central Caribbean with
fresh to locally strong NE winds across the Mona and Windward
passages, and in the Gulf of Honduras. Seas are 8 to 10 ft near
the coast of Colombia. Convection across the basin is related to
the tropical waves.

For the forecast, fresh to strong trade winds will dominate most
of east and central Caribbean through midweek, with seas in the 8
to 10 ft range. Fresh to locally strong winds are also expected
in the Windward passage through tonight. A tropical wave over the
eastern Caribbean Sea is expected to form a broad area of low
pressure over the southwestern Caribbean later this week.

...ATLANTIC OCEAN...

Tree tropical waves are moving westward between the W coast of
Africa and the Lesser Antilles. Please, see the Tropical Waves
section for details.

High pressure of 1022 mb is located near Bermuda at 33N64W. Another
1021 mb high pressure is centered south of the easternmost Azores
near 33N25W. The pressure gradient between this system and lower
pressures over W Africa supports an area of fresh to strong NE
winds roughly from 19N-28N and E of 26W, including the Canary
Islands. A frontal trough is between the high pressure systems. A
large area of showers and thunderstorms has developed N of Hispaniola
and covers mainly the waters from 21N-27N between 67W-72W. An
upper-level low spinning near 24N71W is generating this convective
activity.

African dust has reached the Bahamas and South Florida producing
hazy conditons and heat indices in the 100 to 105 degree range
each afternoon. This will persist today.

A surface trough, previously associated with the northern extent
of a tropical wave, will move northward across the central Atlantic
over the next 48-72 hours. Fresh to strong E to SE winds and seas
of 8 to 11 ft will follow the trough. A tropical depression could
form along the trough axis by the end of the week.

For the forecast W of 65W: High pressure located near Bermuda
will dominate the forecast region through at least Wed. Fresh to
locally strong winds are expected N of Hispaniola including the
approaches to the Windward Passage through tonight. The above
mentioned surface trough is forecast to approach from the east on
Thu. The pressure gradient could increase some across the SW N
Atlantic tonight and Wed between high pressure located just N of
Bermuda and the approaching surface trough. Then, expect increasing
winds across the waters between Cuba and the Bahamas by the end
of the week as a tropical system develops over the NW Caribbean.

$$
GR
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