AXNT20 KNHC 231723
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
122 PM EDT Sat Jun 23 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 1200 UTC surface analysis and satellite imagery through
The axis of a tropical wave is near the west coast of Africa along
17W from 03N-15N. The wave shows up well in the TPW product.
Scattered moderate convection associated to this wave is noted
from 05N-09N between 14W and 20W.
The axis of a tropical wave extends from 18N41W to 03N42W, moving
W at 20 kt. African dust surrounds the wave. So, only isolated
moderate convection is noted at the base of this wave.
The axis of a tropical wave is near 58W from 06N to 18N, moving W
at 20 kt. Scattered moderate convection is noted from 08N-10N
between 55W and 60W. This wave approaching Barbados will move
across the eastern Caribbean through tonight, then over the
central and western Caribbean early next week.
The axis of a tropical wave is near 72W from 10N-20N. This wave,
in conjunction with an upper level low, currently located over
Hispaniola, is producing a large area of showers and tstms over
Puerto Rico, Hispaniola and regional waters. Locally heavy rain
is expected. This wave will move across the central Caribbean
today, and will exit the western Caribbean Sun night. Moisture
from this wave will reach eastern Cuba and Jamaica this evening
into tonight, increasing the likelihood of showers with embedded
The axis of a tropical wave is near 86W, and extends across
central America into the eastern north Pacific region. Scattered
to numerous showers and tstms are observed where the wave meets
the monsoon trough, more concentrated on the EPAC. This wave will
move across the remainder of the northwestern Caribbean and
inland central America this afternoon.
The monsoon trough extends off western Africa near 16N16W to
10N20W to 06N28W. The ITCZ continues from 06N28W to 05N50W to
near the coast of Guyana at 07N57W. Outside of the convection
associated with the tropical waves, a cluster of moderate
convection is noted from 04N-07N between 21W-25W. Similar
convective activity is within about 120 nm N of the ITCZ axis
W of 50W.
GULF OF MEXICO...
An upper-level low spinning near the coast of Mexico, roughly
between Tampico and Tuxpan is helping to induce some showers and
tstms across the E Bay of Campeche. The low will drift westward
into Mexico through Sun night, and continue to enhance convection
across this area. SE wind flow will continue to transport
abundant tropical moisture from the Yucatan Peninsula into the
western Gulf the remainder of the weekend.
A 1018 mb high pressure is located just off SW Florida near
26N83W. A weak ridge extends from this high toward the coast of
Texas. The ridge will drift to over the northern gulf early next
week. Southeast return flow will increase over the western Gulf
between the ridge and weak low pressure over northern Mexico
beginning tonight. A trough moving west off the western coast of
the Yucatan Peninsula each night will further enhance overnight
winds over much of the southwestern gulf waters.
A tropical wave is over the western Caribbean and Central America.
Another tropical wave is moving across Hispaniola. Please, see
Tropical Waves section for more details. Expect increasing showers
and isolated thunderstorms in association with the passage of
these tropical waves.
Recent scatterometer data provide observations of fresh to strong
winds across the south-central Caribbean, with mainly fresh winds
over the remainder of the central Caribbean and the eastern part
of the basin. Gentle to moderate E-SE winds prevail over the NW
Caribbean. The trade winds over the south central Caribbean will
strengthen and expand in areal coverage across just about the
entire basin through early next week as high pressure builds
across the central Atlantic. Winds could reach near gale force
along the coast of Colombia tonight. Seas are forecast to build to
10-12 ft over the south-central Caribbean with the strongest winds.
Fresh to strong winds are also expected in the Gulf of Honduras
at night through at least Mon night.
High pressure of 1029 mb centered near 31N47W extends a ridge
westward across the forecast area. The most recent scatterometer
passes indicate fresh to locally strong trade winds along the
southern periphery of the ridge, particularly S of 18N W of 43W.
This high pressure will slowly shift westward through tonight,
then remain nearly stationary near 30N55W through Tue night. The
tightening pressure gradient over the central Atlantic will
continue to support fresh to strong trade winds and seas of 8-9
ft E of the Lesser Antilles to about 45W through tonight. Then,
the aerial extent of the fresh to strong trades will decrease on
Sun, covering mainly the waters E of the lesser Antilles to about
50W. Fresh to strong winds are also expected off Hispaniola at
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