AXNT20 KNHC 122355
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
754 PM EDT Sun Aug 12 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
GALE-FORCE WINDS NEAR THE COAST OF COLOMBIA AND IN THE GULF OF
NE-to-E GALE-FORCE WINDS are forecast tonight along the coast of
Colombia from 11N to 13N between 70W and 76W, including in the
Gulf of Venezuela. Expect sea heights to range from 9 feet to 13
feet, in the Caribbean Sea but not in the Gulf of Venezuela.
Expect the GALE-FORCE wind conditions to end around sunrise on
Monday, slowing down to less than gale-force. Please read the High
Seas Forecast, that is listed under the WMO/AFOS headers, as
FZNT02 KNHC/MIAHSFAT2, for more details.
An Atlantic tropical wave is along 19W from 19N southward.
Scattered moderate rainshowers are from 05N to 10N between land
and 20W. It is easily possible that some of this precipitation
also is related to the monsoon trough.
An Atlantic tropical wave is along 41W from 21N southward.
Isolated moderate rainshowers are from 07N to 20N between 33W and
44W. It is easily possible that some of this precipitation also is
related to the monsoon trough.
An Atlantic tropical wave is along 52W from 21N southward.
Scattered moderate rainshowers are from 07N to 11N between 49W
and 61W. It is easily possible that some of this precipitation
also is related to the monsoon trough.
A Caribbean tropical wave is along 70W from 21N southward, from
the east Hispaniola to NW Venezuela. Scattered moderate
rainshowers cover the areas that are from 18N to 26N between 68W
and 70W, including in eastern sections of the Dominican Republic.
Isolated moderate to locally strong rainshowers are elsewhere from
12N in the Caribbean Sea to 27N in the Atlantic Ocean between 64W
The monsoon trough passes through the coastal sections of Africa
near 12N17W to 09N35W. The ITCZ is along 09N42W to 10N52W.
Scattered moderate convection is within 75 nm south of the monsoon
trough between 16W-30W.
GULF OF MEXICO…
An upper level cyclonic circulation center is near 23N98W, along
the coast of Mexico.
A separate area of upper level cyclonic wind flow, with a weak
cyclonic circulation center/an inverted trough, spans the Gulf of
Mexico from 23N southward from the Yucatan Channel westward. Upper
level NE wind flow covers the rest of the Gulf of Mexico from 90W
eastward. Some of the NE wind flow is related to a Bahamas upper
level trough/cyclonic circulation center. Scattered moderate
convection covers the Gulf of Mexico from 90W eastward.
A surface ridge passes across the NW Bahamas and Lake Okeechobee,
to a 1020 mb high pressure center that is near 27N89W, near the
center of the Gulf of Mexico.
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. A surface ridge will prevail elsewhere across the
area. The ridge will support moderate to locally fresh SE winds
in the west central and NW Gulf during most of the forecast
Please read the SPECIAL FEATURES section for more details about
the Gale Warning in effect.
An upper level trough continues from the Bahamas into the entire
western section of the Caribbean Sea. Upper level cyclonic wind
flow covers the Caribbean Sea from the Windward Passage westward.
Isolated moderate to locally strong rainshowers are to the west of
the line from the Windward Passage to the northern coast of Panama
that is along 80W.
The monsoon trough is along 09N from 74W in Colombia beyond
southern Costa Rica. Other rainshowers are possible also from 12N
southward from 76W westward.
Broken to overcast multilayered clouds and possible rainshowers
are moving into the easternmost part of the Caribbean Sea, from
14N to 20N between 60W and 64W.
High pressure, that is to the north of the area, will support
fresh to strong winds in the south central Caribbean Sea through
Tuesday. It is possible that sustained wind speeds may reach gale
force along the coast of Colombia and in the Gulf of Venezuela
tonight and Monday morning. The wind speeds and the sea heights
in the Caribbean Sea will subside during the middle of the week,
as the surface ridge that is in the western Atlantic Ocean weakens
An upper level inverted trough is on top of the Bahamas. Upper
level cyclonic wind flow spans the Atlantic Ocean from 70W
westward. Widely scattered to scattered moderate and isolated
strong rainshowers cover the Bahamas and surrounding waters from
23N to 28N between 77W and 80W. Isolated moderate rainshowers are
elsewhere from 70W westward.
A surface ridge extends from a 1026 mb high pressure center that
is near 33N34W, to 30N40W, to a 1026 mb high pressure center that
is near 30N57W, to the NW Bahamas, and eventually, across Lake
Okeechobee and south Florida, into the central Gulf of Mexico.
The surface ridge will remain in place during the next several
days. The ridge will help to maintain fresh to locally strong
winds along the northern coast of Hispaniola, and in the
approaches to the Windward Passage, during the evening and
nighttime hours. Gentle to moderate anticyclonic wind flow will
continue, elsewhere, N of 23N, and mainly moderate easterly wind
flow will prevail S of 23N.
For additional information please visit