[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121707
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Mon Jul 12 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
1700 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave is along 38W from 11N southward and
moving W at 15 to 20 kt. Scattered moderate convection is seen
from 08N to 11N between 37W and 39W.

Another weaker Atlantic tropical wave is near 50W from 09N
southward and moving W near 15 kt. Scattered moderate convection
is noted ahead of the wave axis to the coast of Guyana from 06N
to 09N.

A robust Caribbean tropical wave extends from Haiti to northeast
Colombia, moving W at 10 to 15 kt. Aided by upper- level
divergent winds, scattered to numerous showers and thunderstorms
are present across the Turks and Caicos Islands, Dominican
Republic and over waters south of Hispaniola .

The Caribbean tropical wave previously located over Honduras,
Nicaragua and Costa Rica has moved in the E Pacific and will be
included in the Pacific Discussion.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near 11N16W
to 08N28W to 07N37W. The ITCZ then continues from 07N39W to
07N47W. In addition to the convection listed in the Tropical Wave
section, scattered moderate to isolated strong convection is
evident near the monsoon trough from 05N to 10N between 15W and
30W, and from 08N to 11N between 40W and 45W.

...GULF OF MEXICO...

A surface ridge extends west-southwestward from northern Florida
across the northern Gulf to South Texas. A scatterometer pass from
1500 UTC confirmed this pattern is supporting mostly gentle to
moderate E to SE winds over most of the basin. Seas are mainly 2
to 4 ft. A few showers and thunderstorms are noted over the
northwestern Gulf, the Straits of Florida, and over the warmer
Loop Current of the south-central Gulf.

For the forecast, the gentle to moderate SE winds will persist
across most of the Gulf, south of the surface ridge. The ridge
will lift just north of the area through today, maintaining gentle
to moderate winds and slight to moderate seas through Fri. The
exception will be fresh to occasionally strong winds off the
northwest Yucatan Peninsula and eastern Bay of Campeche during
overnight hours through mid week, related to the surface trough
that forms during the late afternoon each day.

...CARIBBEAN SEA...

Please refer to the Tropical Waves section above for details on
convection in the basin.

Scatterometer data from this morning noted 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 9 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 to isolated strong convection is ongoing off Costa Rica
and southeastern Nicaragua.

For the forecast, the tropical wave reaching from Haiti to
northeast Colombia will move west of the basin into mid week.
High pressure centered north of the region will build in the wake
of the tropical wave, supporting 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 Grand Bahama Island
is supporting clusters of scattered moderate to isolated strong
convection over the Cay Sal area of the Bahamas and across the
southern Bahamas and Turks and Caicos Islands.

For the forecast, the surface ridge from the north-central
Atlantic through Bermuda to central Florida will lift north to
along 32N through Tue. An active tropical wave over Haiti will
move quickly westward across the central Caribbean and bring a
surge in wind and waves to the Atlantic waters north of Hispaniola
and Cuba and across the Turks and Caicos Islands and southern
Bahamas late today and 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
high pressure weakens.

$$
Mora
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