[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112355
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
755 PM EDT Sat Aug 11 2018

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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURE...

GALE-FORCE WINDS NEAR THE COAST OF COLOMBIA AND IN THE GULF OF
VENEZUELA...

Frequent gusts to GALE-FORCE are expected to develop tonight near
the coast of Colombia and in the Gulf of Venezuela. Expect NE to
E winds 20 to 30 knots, from 11N to 13N between 70W and 76W. Sea
heights will range from 9 feet to 12 feet. On Sunday night, GALE-
FORCE NE winds are expected within 90 nm of the coast of Colombia,
and frequent gusts to GALE- FORCE winds in the Gulf of Venezuela.
The sea heights are forecast to range from 9 feet to 13 feet.
Please read the High Seas Forecast, that is listed under the
WMO/AFOS headers, as FZNT02 KNHC/MIAHSFAT2, for more details.

...TROPICAL WAVES...

An Atlantic tropical wave is along 36W from 21N southward.
Scattered showers are from 10N to 16N between 30W and 40W. This
precipitation is related to the proximity of the monsoon trough.

An Atlantic tropical wave is along 47W from 21N southward.
Scattered showers are from 09N to 12N between 40W and 47W. This
precipitation is also related to the proximity of the monsoon
trough.

A Caribbean tropical wave is along 64W from 21N southward.
No significant convection is observed with this wave at this
time.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
west Africa near 14N17W to 08N46W. The ITCZ continues from 08N46W
to 04N50W. Aside from the convection related to the tropical
waves, scattered showers are noted along the boundaries between
30W-50W.

...DISCUSSION...

GULF OF MEXICO...

An upper level cyclonic circulation center is near 24N87W. Upper
level cyclonic wind flow covers the Gulf of Mexico from 90W
eastward. Isolated moderate rainshowers are to the east of the
line that runs from SE Louisiana to the Florida Keys, and from
26N northward from 90W westward.

A surface trough is in the SW corner of the Gulf of Mexico, along
92W/94W, from 22N southward into the Isthmus of Tehuantepec of
southern Mexico. Upper level anticyclonic wind flow covers the
Gulf of Mexico from 26N southward from 90W westward. Scattered
moderate to isolated strong rainshowers are along the coast of
Mexico from 26N southward from 94W westward. Other broken
multilayered clouds and possible rainshowers are elsewhere from
26N southward from 88W westward.

A surface ridge passes across the NW Bahamas, to a 1018 mb high
pressure center that is near 27N88W, and it continues to the lower
Rio Grande Valley of Texas. Gentle to moderate anticyclonic wind
flow covers much of the Gulf of Mexico. Light to gentle winds
cover the NE part of the area. The sea heights are in the range of
1 foot to 2 feet in the NE corner of the area, and in the range
of 2 feet to 4 feet elsewhere.

The current surface ridge will prevail across the area through
early next week. The ridge will support moderate to fresh SE
winds in the west-central and NW Gulf. A nocturnal trough moving
off the Yucatan peninsula will induce a surge of fresh to strong
NE to E winds in the Bay of Campeche each night.

CARIBBEAN SEA...

An upper level cyclonic circulation center is near 23N73W in the
Atlantic Ocean. A trough extends from the 23N73W cyclonic center
to 14N76W in the Caribbean Sea. Upper level cyclonic wind flow
covers the Caribbean Sea from 14N northward between 63W and 84W.
Isolated moderate rainshowers are from 15N northward between the
Mona Passage and 83W.

The monsoon trough is along 08N/09N, from 73W in Colombia beyond
southern Costa Rica. Widely scattered moderate to isolated strong
rainshowers are from 12N southward from 80W westward, in the
coastal plains/coastal waters from Panama to Costa Rica to
Nicaragua.

High pressure, that is to the north of the area, will support
fresh to strong winds in the south central Caribbean Sea through
Tuesday. Frequent gusts to gale force are expected in the Gulf of
Venezuela and near the coast of Colombia tonight and Sunday night.
It is possible that sustained wind speeds may reach gale force
along the coast of Colombia on Sunday night. One tropical wave is
entering the eastern Caribbean Sea. The next tropical wave will
enter the Caribbean Sea on Monday night.

ATLANTIC OCEAN...

An upper level cyclonic circulation center is near 23N73W. A
trough extends from the 23N73W cyclonic center to 14N76W in the
Caribbean Sea. Upper level cyclonic wind flow covers the Caribbean
Sea from 14N northward between 63W and 84W. Isolated moderate to
locally strong rainshowers cover the Atlantic Ocean from the
Greater Antilles northward elsewhere from 60W westward.
Rainshowers that are associated with a 62W/63W tropical wave are
from 18N to 23N between 60W and 65W.

An upper level cyclonic circulation center is near 36N49W. Upper
level cyclonic wind flow covers the Atlantic Ocean from 28N
northward between 40W and 58W. Isolated moderate rainshowers are
from 28N northward between 44W and 57W.

A surface ridge extends from a 1030 mb high pressure center that
is near 35N30W, through 32N42W, to 27N56W 27N73W, across the south
Florida peninsula, to a Gulf of Mexico 1020 mb high pressure
center that is near 25N87W.

The current surface ridge will remain in place during the next
several days. The ridge will help to maintain gentle to moderate
anticyclonic flow N of 22N, and mainly moderate easterly winds
will prevail S of 22N. This scenario will support fresh to
locally strong winds along the N coast of Hispaniola and the
approaches to the Windward Passage during the evening and
nighttime hours.

For additional information please visit
http://www.hurricanes.gov/marine

$$
ERA/MT
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