[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152318
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Aug 16 2023

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is over west Africa near 15W from 04N
to 18N, moving W at 10-15 kt. Numerous moderate with isolated
strong convection is occurring from 05N to 18N between 25W and
the west coast of Africa. The tropical wave is forecast to move
off the west coast of Africa tonight or early Wednesday. Some slow
development of this system is possible later this week or over
the weekend while it moves generally west-northwestward or
northwestward across the eastern Atlantic. Environmental
conditions are expected to become unfavorable for development by
early next week. There is a low chance for tropical cyclone
development over the next 7 days.

The axis of an Atlantic Ocean tropical wave is near 35W, from 18N
southward, moving W at 15 kt. Scattered moderate convection is
noted from 07N to 16N between 31W and 40W. Development, if any,
of this system should be slow to occur while it moves generally
west-northwestward at about 15 mph across the tropical Atlantic
through the end of the week. There is a low chance for tropical
cyclone development over the next 7 days.

The axis of an Atlantic Ocean tropical wave is near 58W, from 21N
southward, moving W at 15-20 kt. Scattered moderate convection is
noted from 11N to 13N between 57W and 60W, including over
Trinidad and Tobago.

The axis of a Caribbean Sea tropical wave is near 82W, from 19N
southward through Panama and into the east Pacific, moving W at
15-20 kt. Upper-level diffluence to the east of an upper-level low
centered over Belize and northern Guatemala is enhancing
scattered moderate isolated strong convection across the western
Caribbean from 10N to 28N between 80W and 86W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal Mauritania near 18N16W
to 13N35W to 09N55W. See the Tropical Waves section
above for a description of showers and thunderstorms.

GULF OF MEXICO...

A high pressure ridge stretches across the central Gulf of Mexico
from east to west. Weak surface troughing is over the Bay of
Campeche, where moderate E winds prevail along with 3-4 ft seas.
Light to moderate winds prevail elsewhere with 1-3 ft seas.
Scattered thunderstorms are seen over the NE Gulf from 24N to 30N
and west of 85W. Isolated showers and tstorms are near the coast
of Mexico between Veracruz and Tampico. A surface trough over the
eastern Straits of Florida is helping scattered thunderstorms
persist across the western Straits of Florida and SE Gulf. A
narrow upper- level trough is also producing some cloudiness and
isolated showers and tstorms across the west-central Gulf.

For the forecast, a trough will move off the Yucatan Peninsula each
night through late week, supporting fresh winds off northwest
Yucatan. Elsewhere, a ridge over the Gulf will support mostly
gentle to moderate winds and slight seas across the basin
through Sat.

CARIBBEAN SEA...

See the Tropical Waves section above for a description of showers
and thunderstorms occurring across the basin. No significant
precipitation is noted north of 12N and east of 77W, due to dry
Saharan dust over the eastern two-thirds of the Caribbean, as
noted on the GOES-16 CIMSS Saharan Air Layer Tracking Product.

Earlier ASCAT data depicted fresh E trade winds across the
eastern and central Caribbean. Recent buoy and altimeter data show
seas of 6 to 7 ft across much of the basin, east of 80W. In the
south- central basin, off the coast of Colombia, earlier ASCAT
shows strong ENE winds with seas likely range 7 to 8 ft. Moderate
or weaker winds and 2 to 5 ft seas prevail across the western
Caribbean.

For the forecast, ridging over the western Atlantic will support
fresh to locally strong winds across mainly the south-central
Caribbean into Wed. Moderate winds and seas will prevail
otherwise.

ATLANTIC OCEAN...

A surface trough is moving westward over the eastern Straits of
Florida, from 27N7.5W to 24N81W. Scattered thunderstorms are
noted from 22N to 269, and west of 72W through the Straits of
Florida. Scattered moderate convection is also noted offshore NE
Florida, north of 28N and W of 80W.

An upper-level low centered near 26N68W is only able to induce
isolated showers and tstorms from 22N to 29N between 65W and 70W
as a large plume of dry Saharan dust has recently caught up with
the upper-low.

Surface ridging dominates the remainder of the basin, anchored by
a 1024 mb high pressure center near 34N41W. A surface ridge axis
extends WSW from that high to the NW Bahamas. Moderate to fresh
NE to E trade winds from 15N to 26N between 35W and 60W, where
seas are 6 to 8 ft. Earlier ASCAT data depicted moderate to fresh
ESE trades north of Hispaniola through the SE Bahamas and in the
Windward Passage, where seas are likely 4 to 5 ft. Gentle to
moderate wind speeds are farther north, closer to the ridge axis.
Over the far NE Atlantic, from the Canary Islands to the coast of
Western Sahara, fresh to strong NE winds and seas of 7 to 8 ft
prevail. Of note, a dry airmass due to Saharan dust covers much of
the basin from 13N to 27N, and east of 70W.

For the forecast W of 55W, fresh to locally strong winds will pulse off
Hispaniola this evening. Fresh E winds will form S of 25N starting
Thu. A cold front will approach the NW waters then stall, but
fresh SW winds can be expected Thu and Thu night in the NW waters.
Gentle to moderate winds will prevail elsewhere.

$$
AReinhart
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