[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142146
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
2110 UTC.

...TROPICAL WAVES...

A tropical wave is in the Atlantic Ocean near 34W/35W from 15N
southward, moving W at around 15 to 20 kt. Scattered moderate
convection is noted from 08N to 09N between 35W and 37W. The
northern portion of the wave is surrounded by SAL.

A tropical wave is in the Atlantic Ocean near 57W from 15N
southward to across Suriname, moving W at around 15 kt. Scattered
moderate convection is noted from 10N to 15N between 55W and 58W,
and from 07N to 12N between 52W and 55W.

A tropical wave is over the Yucatan Peninsula near 91W from 22N
southward, moving W at around 10 to 15 kt. Scattered moderate
convection is noted across portions of the Yucatan Peninsula.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from Guinea-Bissau
near 11.5N15W to 09N33W. The ITCZ continues from 08N36W to
07N54W. Scattered moderate convection is noted from 07N to 10N
between 14W and 18W, from 05N to 11N between 22W and 32W, and from
02N to 07N between 36W and 39W.

GULF OF MEXICO...

A southeastern U.S.A. ridge extends across most of the lower
Mississippi Valley. Gentle to moderate E-SE flow prevails across
the basin, locally moderate to fresh just north of the northern
Yucatan Peninsula coast. Seas are mainly in the 2 to 4 ft range
across the basin. Scattered moderate convection is noted in the SW
Gulf from 18N to 23N between 92W and 97W. Isolated to scattered
showers and thunderstorms are noted across the waters north of 26N
and west of 87W, as well as across the western Florida Peninsula
extending into the Florida Gulf coastal waters.

For the forecast, a surface high pressure ridge over the SE
United States will maintain gentle to moderate E to SE winds and
slight to moderate seas across much of the Gulf through Fri. A
surface trough will develop each day over the Yucatan and shift
westward into the SW Gulf. This will support fresh to occasionally
strong winds off the northwest Yucatan Peninsula and eastern Bay
of Campeche during the overnight hours through Thu night. Looking
ahead, the northern end of a tropical wave will move through the
southeast Gulf Fri and across the central Gulf Sat and Sun,
bringing a slight increase in winds and seas to the Straits of
Florida Fri night into Sat.

CARIBBEAN SEA...

Please refer to the Tropical Waves section for details on a
tropical wave over the Yucatan Peninsula.

An upper level trough extends from the Atlantic Ocean, across the
Greater Antilles, into the southern Caribbean Sea. Dry, subsident
northerly flow aloft is suppressing showers and thunderstorms
across much of the central and western Caribbean Sea. Scattered
showers and isolated thunderstorms are within 60 nm of the coasts
of Panama and Costa Rica, as well as across Hispaniola and
northern South America.

Fresh to strong trade winds are noted in the south-central
Caribbean and in the vicinity of the Gulf of Honduras. Moderate
trades prevail elsewhere, locally fresh across the Windward
Passage, and except gentle to moderate in the SW Caribbean south
of 10N. Seas are mainly in the 4 to 6 ft range across the basin,
except 7 to 11 ft from 10N to 15N between 74W and 82W due to the
stronger winds.

For the forecast, high pressure north of the region will continue
to support fresh to strong tradewinds and rough seas over the
south-central Caribbean. Fresh to strong NE to E winds are
expected in the Gulf of Honduras through tonight. Winds and seas
will diminish Thu and Fri as the high pressure weakens, although
areas of fresh to strong winds will continue to pulse in the Gulf
of Venezuela and near the coast of NE Colombia. Looking ahead,
tradewinds and related seas will increase over the south-central
Caribbean and slightly around the Leeward Islands Sat into Sun as
another tropical wave reaches the eastern Caribbean.

ATLANTIC OCEAN...

Please refer to the Tropical Waves section for details on two
tropical waves in the Atlantic Ocean.

Gentle to moderate anticyclonic wind flow covers most of the
Atlantic basin. Fresh to strong N-NE winds are occurring from 18N
to 31N west of the coast of Africa to 30W due to a locally tight
pressure gradient. A pair of surface high pressure centers are in
the central Atlantic just north of the area, 1026 mb near 34N51W
and 1025 mb near 33N46W. Seas of 3 to 6 ft dominate the waters
west of 30W, except around 3 ft just south of the high pressure
centers. Seas are 6 to 9 ft near the fresh to strong winds off the
coast of Africa.

A large upper level trough is just to the north of Puerto Rico. A
weak surface trough is located from 30N59W to 24N62W. A few
showers and thunderstorms are noted within 60 nm to the west of
the trough. A 1026 mb high pressure center is just north of the
area near 33N74W.

For the forecast for the waters west of 65W, a high pressure
ridge just north of the area, off the Carolina and Georgia
coasts, will maintain gentle to moderate E winds across the
western Atlantic. Looking ahead, winds and seas will build
slightly Sat south of 22N and north of the Leeward Islands as a
tropical wave approaches the region from the east. Expect fresh to
strong winds to pulse off Hispaniola Sat through Mon.

$$
Lewitsky
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