[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200442
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1240 AM EDT Mon Jul 20 2020

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0430 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is along 33W from 02N-19N, moving
west at 10-15 kt. Scattered showers are noted south of 12N within
the monsoon trough.

The axis of a tropical wave is along 41/42W from 02N-17N, moving
west at 10 kt. Scattered showers are noted in the vicinity of
the wave mainly south of 11N, within the monsoon trough.

The axis of a tropical wave is along 57W from 03N-21N, moving
west at 10 kt. Scattered showers are noted near the wave axis
from 08N-13N.

The axis of a tropical wave is along 74/75W from 06N-24N, moving
west at 10 kt. Scattered moderate showers and isolated tstorms
are seen from 17N-24N between 72W-77W, including Haiti, eastern
Cuba and the southeast Bahamas.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 19N16W
to 13N22W to 08N40W. The ITCZ continues from 07N44W to 08N55W.
Aside from the convection related to the tropical waves
described above, scattered moderate showers are noted with the
monsoon trough from 08N-12N between 15W-40W, and along the ITCZ
between 46W-55W.

GULF OF MEXICO

A surface trough is analyzed in the central Gulf from 27N92W to
20N91W. The surface trough and upper-level divergence over the
north-central Gulf are contributing to scattered moderate showers
and isolated tstorms north of 24N between 87W-91W, and from
27N-29N between 91W-93W. Scattered showers and isolated tstorms
are also seen east of 87W from 22N-26N, including the Florida
Straits. Scattered moderate convection is over the far eastern
Bay of Campeche. A recent ASCAT pass shows fresh E winds
extending from the coast of Louisiana southward for 120 nm.

The northern extent of the tropical wave that is currently along
74/75W, will move into the SE Gulf on Tue, then move westward
across the central and W Gulf through Thu night. Increasing winds
and seas are possible by midweek in association with this
system.

CARIBBEAN SEA...

See the section above for information on the tropical wave in the
central Caribbean.

An upper-level trough axis extends over the Bahamas westward
through the Florida Straits. Upper-level diffluence to the south
of the upper-level trough axis is enhancing scattered moderate
convection across the NW Caribbean Sea, north of 17N between
77W-85W, including over portions of Cuba, Haiti and Jamaica.
GOES-16 water vapor channels show drier low to mid-level air
over the southern Caribbean from 11N-16N. A recent ASCAT pass
shows fresh trades across the central Caribbean between
68W-77W, locally strong off the coast of NW Venezuela.

The pressure gradient between high pressure north of the area and
low pressure over Colombia will maintain fresh to strong trade
winds over the south-central Caribbean this week. Elsewhere,
gentle to moderate trade winds will persist across the region for
the next several days. Expect increasing winds and seas E of 65W
Tue night through Fri night as high pressure builds across the
western Atlantic.

ATLANTIC OCEAN...

A broad upper-level trough extends over the SW N Atlantic,
Bahamas and Florida Straits. A weak surface trough is analyzed
from 29N69W to 23N73W. The northern end of a tropical wave is
also moving through the region, extending northward from the
Windward Passage to near 24N74W. As a result of the
aforementioned features, scattered moderate showers and
isolated tstorms are present over the Florida Straits, Old
Bahama Channel and across the Bahamas. Isolated showers are
farther NE near the surface trough. A recent ASCAT pass shows
fresh trades for the waters within 210 nm north of the Greater
Antilles between 65W-80W, including most of the Bahamas.
Locally strong east winds are along the north coast of
Hispaniola extending out 90 nm. Farther east, there are three
surface troughs containing isolated showers. These troughs
extend from 32N49W to 27N58W, from 30N44W to 24N46W, and from
22N55W to 16N55W, respectively. A 1021 mb surface high is
centered east of Bermuda. The surface ridge axis extends
generally east-west along 31/32N. As a result, light to
gentle winds are found in the 26N-33N latitude band between
35W-80W.

A high pressure ridge north of the area will support pulses of
fresh to strong winds off Hispaniola and near the entrance to
the Windward Passage for the next several nights. Expect
fresh winds to continue over the waters S of 25N through early
this week as the northern extent of a tropical wave, currently
along 74W, moves westward. Winds and seas will increase E of 65W
Tue night through Fri night as high pressure builds across the
western Atlantic.

$$
Hagen
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