[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111657
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Jul 11 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 near 28W from 12N southward and
moving W at 20 kt. Scattered moderate convection is within 200 nm west
of the wave from 07N to 10N.

Another Atlantic tropical wave is along 41/42W from 10N southward
and moving W at 10 to 15 kt . No significant convection is noted
with this wave.

A Caribbean tropical wave is near 61W from 21N southward moving W
10 kt. This wave has been repositioned to the east based on upper
air soundings from the eastern Caribbean. Scattered moderate
convection is present within 300 nm west of the trough axis, north
of 10N.

Another Caribbean tropical wave is along 81W from 15N southward
to western Panama, moving W at 10 kt. Scattered moderate to
isolated strong convection is flaring up over the SW Caribbean
basin from 10N to 16N west of 77W

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
12N16W to 09N24W to 08N33W. Segments of the ITCZ extend from
08N33W to 08N40W, and from 08N42W to 09N53W. Scattered moderate
convection associated with the monsoon trough is from 07N to 11N
between 14W to 24W. Scattered moderate convection associated with
the ITCZ is from 08N to 11N between 46W to 52W.

GULF OF MEXICO...

A surface ridge extends westward from the western Atlantic across
the northern Gulf to South Texas. Divergent upper- level winds
are coupling with convergent SE winds along the surface ridge to
trigger scattered convection over the southeast Gulf. A recent
scatterometer satellite pass noted moderate SE winds over the
western Gulf between a ridge extending from the western Atlantic
to the north central Gulf and lower pressure over northern Mexico.
Moderate to fresh E winds are noted in the Florida Straits with
gentle to moderate E-SE winds noted elsewhere. Seas are 1 to 2 ft
in the northeast part of the basin with 3 to 5 ft seas elsewhere.

For the forecast, the ridge will lift north of the area through
Mon. This will support gentle to moderate winds and slight to
moderate seas through mid week. 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 see the Tropical Wave section for information on
convection.

Scatterometer data from this morning notes fresh to strong trade
winds across the eastern and central Caribbean, driven by the
pressure gradient between the subtropical high north of the area
and lower pressure over Colombia and W Venezuela. Seas range from
6 to 10 ft except in the far SE Caribbean where seas are 3 to 5
ft. Moderate trades and seas of 2 to 4 ft are within the
northwestern portion of the basin, including the Gulf of
Honduras.

For the forecast, the tropical wave in the eastern Caribbean will
move through the central Caribbean by tonight through Tue, and
then west of the basin through 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, to
include strong NE winds across the Windward Passage Tue night.
Winds and seas will diminish through late Thu.

ATLANTIC OCEAN...

Please see the section above for information the tropical waves
moving across the basin.

A surface high centered near 36N50W supports gentle to moderate
anticyclonic flow across the basin north of 25N and west of 40W
with 3 to 5 ft seas. An upper low centered just east of the
central Bahamas is supporting scattered showers and thunderstorms
near the approaches to the Windward Passage, and north of the
Leeward Islands where the tropical wave is present. A few showers
and thunderstorms is noted off northeast Florida over the Gulf
Stream. The gradient between the surface ridge extending from
near Bermuda to central Florida and a tropical wave over the
eastern Caribbean supports moderate to fresh trade winds south of
25N west of 35W, with 6 to 8 ft seas in open waters. Moderate to
fresh NE winds and 5 to 7 ft seas are noted east of 35W.

For the forecast west of 65W, the surface ridge from Bermuda to
central Florida will lift north of the area through tonight. A
large tropical wave moving across the eastern Caribbean will bring
a surge in wind and waves to the Atlantic waters north Leeward
Islands and Puerto Rico today, north of Hispaniola tonight
through Mon, then across the Turks and Caicos Islands and southern
Bahamas late Mon and Tue. Winds and seas will diminish across the
region by mid week as high pressure builds across the region in
the wake of the tropical wave.

$$
Mora
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