[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151728
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Thu Jul 15 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...

A tropical wave is in the E Atlantic from 05N to 21N with axis
along 21W, moving west at 10-15 kt. The wave is mainly analyzed
from 700 mb trough diagnostics. Scattered moderate to isolated
strong convection is noted from 07N-13N between the west coast of
Africa to 20W.

A tropical wave is in the central Atlantic extending from 02N to
21N with axis along 38W, moving west at around 15 to 20 kt. A
surface reflection is noted on the ASCAT pass from around 12Z. The
wave is surrounded by Saharan Air Layer, limiting the shower
activity.

A tropical wave is near the Lesser Antilles extending from 06N to
16N with axis near 61W, moving west at around 15 kt. The wave is
noted in the Barbados and Trinidad 700 mb winds, but it is
negligible at the surface. Scattered moderate convection extends
from the northeast coast of Venezuela to 13N between 57W and 62W.

A tropical wave has been introduced over the central Caribbean
Sea, extending from 04N to 20N with axis near 75W. A surface
reflection is noted on the ASCAT pass from around 15Z. Also, the
wave is observed from 700 mb rawinsonde winds at the Dominican
Republic and Jamaica. No important convection is associated with
this wave.

A tropical wave is over SW Gulf of Mexico and SE Mexico along 96W
extending into the eastern Pacific region. It is moving west at
around 15 kt. The wave is generating scattered moderate convection
over SW Gulf of Mexico.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from northern
Mauritania near 21N17W to 07N37W. The ITCZ continues from 07N40W
to 04N54W. For information about convection, see the tropical
waves section.

GULF OF MEXICO...

A ridge positioned over the SE United States extends north of the
Gulf waters. Gentle to moderate E-SE wind flow prevails across
most of the basin with seas in the 2-4 ft range. Scattered showers
are also noted over the E Gulf in an association with an upper
level trough just west of the convection.

The surface ridging will prevail through the forecast period,
supporting mostly gentle to moderate E to SE winds. Fresh NE winds
will pulse tonight over the waters to the northwest of the
Yucatan Peninsula, associated with a diurnal surface trough moving
into the Bay of Campeche. Heavy showers and isolated
thunderstorms in the SW Gulf associated with a tropical wave will
dissipate early this afternoon as the wave moves W of the area.

CARIBBEAN SEA...

A modest pressure gradient between a 1024 mb Bermuda High and a
1010 mb Colombian Low is promoting strong NE trades just north of
Colombia with fresh and weaker trades prevailing elsewhere across
the Caribbean. Seas are 6-8 ft over the central Caribbean and 3-5
ft elsewhere. An upper level trough extends from the Atlantic
Ocean, across Hispaniola into the south-central Caribbean. Dry air
is suppressing the shower activity across the central and western
Caribbean Sea. Scattered showers are noted north and south of
Jamaica.

For the forecast, high pressure between Bermuda and South
Carolina will continue to support fresh to strong trade winds in
the south-central Caribbean. These winds will prevail through
Friday and then increase in areal coverage as a tropical wave
enters the eastern Caribbean late Saturday and moves into the
central Caribbean late Sunday. Fresh winds will pulse at night in
the Windward Passage through Sunday night.

ATLANTIC OCEAN...

Please refer to the Tropical Waves section above for information
about these features.

An expansive anticyclonic wind flow covers most of the Atlantic
forecast waters. An ASCAT pass around 15Z showed 15 to 20 kt SE
winds over the eastern Bahamas, extending to the coasts of
eastern Cuba and northern Hispaniola, including approaches to the
Windward Passage. Another ASCAT pass around 11Z showed 20 to 25 kt
N-NE between the Canary Islands due to a locally tight pressure
gradient. Seas of 3-6 ft dominate the waters west of 30W while
seas of 5-8 ft are near the fresh to strong winds off the coast
of Western Sahara.

A surface trough is analyzed from 29N62W to 22N67W. A few showers
are noted to the east the trough axis.

For the forecast for the waters west of 65W, surface high
pressure centered off the Carolina coast will maintain moderate
winds across the area, except moderate to fresh south of 23N. A
tropical wave will bring fresh winds to Puerto Rico adjacent
waters Saturday night through Monday night. Fresh to strong winds
will pulse north of Hispaniola through the forecast period,
strongest Sat night through Monday night.

$$
RUBIO/DELGADO/LANDSEA
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