AXNT20 KNHC 120517
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
117 AM 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 0000 UTC surface analysis and satellite imagery through
Caribbean Gale Warning…
Gale-force are expected tonight near the coast of Colombia and in
the Gulf of Venezuela. A recent scatterometer pass depicted gale-
force winds already occurring over the Gulf of Venezuela. These
conditions will continue through Monday morning. The sea heights
are forecast to range from 9 feet to 13 feet in this area. Please
read the High Seas Forecast, that is listed under the WMO/AFOS
headers FZNT02 KNHC/MIAHSFAT2 for more details.
An Atlantic tropical wave extends its axis along 37W from 21N
southward, moving west at 10-15 kt. This wave is depicted in model
diagnostics and 700 mb streamline analysis, and TPW imagery shows
moderate moisture in its vicinity. Scattered showers are from 10N
to 15N between 35W and 40W.
An Atlantic tropical wave is along 49W from 21N southward, moving
west at 10-15 kt. This wave is also depicted in model diagnostics.
Scattered showers are in the area where the wave meets the ITCZ
mainly south of 10N.
A tropical wave in the eastern Caribbean extends its axis along
66W and south of 21N, moving west at 10-15 kt. Despite the fact
that TPW imagery shows abundant moisture with this wave, no
significant convection is observed at this time.
The monsoon trough passes through the coastal sections of
west Africa near 14N17W to 09N42W. The ITCZ continues from 09N42W
to 09N47, then resumes west of a tropical wave near 08N50W to
06N55W. Aside from the convection related to the tropical waves,
scattered showers are noted along the boundaries east of 25W and
GULF OF MEXICO…
A surface ridge prevails across the basin, anchored by a 1018 mb
high centered near 27N87W. With this, a gentle to moderate
anticyclonic flow prevails across the area. To the southwest, a
surface trough extends over the Bay of Campeche from 22N94W to
19N94W. Abundant cloudiness and scattered showers prevail across
the west Gulf mainly west of 93W. An area of upper level
diffluence prevails across the southeast Gulf waters enhancing
scattered showers currently affecting the Florida Straits and
The surface ridge will prevail across the area through early next
week. The ridge will support moderate to fresh easterly 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.
A Gale Warning is in effect for the south-central Caribbean.
Refer to the section above for details. An upper-level low is
centered near 18N75W. This feature is enhancing convection across
the northwest Caribbean waters mainly north of 20W and west of
74W. A tropical wave extends its axis along 66W. For more
information, refer to the section above. The monsoon trough
extends along 10N between 76W-82W. Scattered showers are noted
across Panama and Costa Rica due to this.
Little change is expected through early next week. The next
tropical wave will enter the eastern Caribbean by late Monday.
An upper level low is centered over the northwest Caribbean near
18N75W. This feature is also enhancing convection across the west
Atlantic, mainly over the Bahamas. Two tropical waves are moving
across the basin. Refer to the section above for details. The
remainder of the basin is under the influence of a surface ridge,
anchored by a 1026 mb high centered near 29N54W and a 1030 mb high
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 also support fresh to
locally strong winds along the N coast of Hispaniola and the
approaches to the Windward Passage during the evening and
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