[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260006
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
806 PM EDT Sat Aug 25 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.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 28W from
05N to 20N, moving westward at 15 kt. Scattered moderate
convection is within 30 nm of line from 12N28W to 11N34W, and
within 30 nm of line from 06N26W to 05N28W to 04N32W. Isolated
showers are elsewhere from 10N to 13N between 27W and 30W.

Another eastern Atlantic tropical wave has its axis along 36W/37W
from 04N to 19N, moving westward at 10-15 kt. Broken to overcast
multilayer clouds along with scattered moderate isolated strong
convection are noted where the wave axis crosses the monsoon
trough, and to the south of the monsoon trough. The scattered
moderate isolated strong convection is occurring from 05N to 07N
between 35W and 37W. Scattered moderate isolated strong convection
is within 30 nm of line from 11N34W to 11N37W. Scattered showers
and isolated thunderstorms are seen along the monsoon trough
within 120 nm east of the wave and between the trough and 10N
within 120 nm east of the wave.

A central Atlantic tropical wave has its axis along 54W from 03N
to 19N, moving westward at 15 kt. Isolated showers and thunderstorms
are within 60 nm either side of the wave south of 08N.

A central Caribbean Sea tropical wave has its axis along 72W south
of 19N to well inland S America, moving westward at 10-15 kt. This
wave is moving into an area of pre- existing upper level cyclonic
wind flow. Isolated showers are possible within 120 nm on either
side of the wave.

The earlier mentioned western Caribbean Sea tropical wave has recently
moved to just inland Belize, the far southern Yucatan Peninsula
and well inland Honduras. It is moving westward at 10 kt. Broad
upper level cyclonic wind flow spans the western Caribbean Sea,
with upper level cyclonic circulation centers and troughs. Widely
scattered moderate to isolated strong rainshowers are in the
waters that are from 80W westward. Isolated moderate rainshowers
are elsewhere from the Windward Passage westward.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from coast of Senegal near
14N17W, to 10N23W, 09N30W, 08N36W, and 07N39W. The ITCZ continues
from 07N39W to 05N45W and 05N50W. Aside from convection associated
with the tropical waves, scattered moderate convection is south
of the trough axis within 30 nm of a line from 06N12W to 07N15W to
07N20W, and also within 30 nm of 07N23W.

...DISCUSSION...

GULF OF MEXICO...

A narrow NE-to-SW oriented upper level trough extends from 32N81W
near the South Carolina/ Georgia border, across NE Florida, to
28N83W in the NE corner of the Gulf of Mexico, to 23N88W in the
Gulf of Mexico.

A surface trough will develop during the evening hours in the
Yucatan Peninsula, before pushing offshore into the SW corner of
the Gulf of Mexico each night. A surge of moderate to fresh NE to
E winds will accompany this trough. A surface ridge will dominate
the rest of the Gulf waters, supporting a gentle to moderate wind
flow.

CARIBBEAN SEA...

An upper level trough extends from an Atlantic Ocean 23N62W cyclonic
circulation center, into the NE corner of the Caribbean Sea near
18N63W and 16N70W. Isolated showers are seen east of 70W.

An upper level inverted trough extends from the SW corner of the
Caribbean Sea, across Nicaragua and Honduras, to the southern half
of the coast of the eastern side of the Yucatan Peninsula. Widely
scattered moderate to isolated strong rainshowers are in the
waters that are from 80W westward. Isolated moderate rainshowers
are elsewhere from the Windward Passage westward.

Fresh to strong winds and building seas to 9 or 10 ft will
prevail in the south-central Caribbean Sea through the forecast
period. Tropical waves will continue to move across the basin,
elsewhere, producing some convective precipitation and little
impact in winds and seas. It is possible that the wind speeds and
the sea heights may be higher near thunderstorms.

ATLANTIC OCEAN...

An upper-level cyclonic circulation center is over the central
Bahamas. A second cyclonic circulation center is near 29N67W.
Instability provided by these features on an already very moist
and unstable atmosphere is allowing for scattered showers and
thunderstorms to continue over the waters west of 74W. Scattered
showers and isolated thunderstorms are seen from 24N to 27N
between 68W and 71W. Isolated moderate showers are elsewhere west
of 70W westward. Isolated moderate rainshowers are in the Gulf of
Mexico from 94W eastward.

An upper-level trough extends from a 34N18W cyclonic circulation
center, to 34N35W, to a second cyclonic circulation center that is
near 29N46W. The trough continues to a third cyclonic circulation
center that is near 23N62W, into the NE corner of the Caribbean
Sea near 18N63W and 16N70W. Isolated moderate rainshowers are
within 300 nm on either side of the trough from 27N northward
between 40W and 55W, and elsewhere from 20N northward between 50W
and 72W. A surface trough is along 27N67W 24N70W 20N72W to the
north of Hispaniola and at the SE end of the Bahamas.

A surface trough, that is near the SE Bahamas, is forecast to
move across the area through Monday. Gentle to moderate winds
will be associated with this trough. Winds will pulse to fresh to
strong during the evening and nighttime hours just N of
Hispaniola through the middle of next week. A surface ridge will
dominate the rest of the forecast area, supporting a gentle to
moderate anticyclonic flow.

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

$$
Aguirre
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