[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162323
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Aug 17 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 approaching the Cabo Verde Islands
along 26W, from 17N southward, moving W at 15 kt. This tropical
wave is producing a large area of disorganized showers and
thunderstorms. This system is forecast to move toward the west-
northwest at about 15 mph, with an area of low pressure expected
to form in a day or so just to the west of the Cabo Verde Islands.
Further development of the low is possible, and a tropical
depression could form over the weekend before environmental
conditions become unfavorable early next week. This system has a
low chance of developing in 48 hours and a medium chance in 7
days.

An axis of a tropical wave is in the central Atlantic along 42W,
from 16N southward, moving W at 15 kt.  Scattered moderate and
isolated strong convection is noted from 09N to 15N between 39W
and 46W. Environmental conditions appear conducive for gradual
development of this system, and a tropical depression could form
during the next several days while moving toward the west or west-
northwest at about 10 kt across the central tropical Atlantic. This
system has a low chance of developing in 48 hours and a medium
chance in 7 days.

The axis of a tropical wave is in the E Caribbean near 65W, from
19N southward, moving W at 15 kt. Convection previously
associated with this wave has generally diminished today.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes near coastal Senegal near 15N17W to
11N29W to 10N47W. The ITCZ continues from 10N47W to 10N61W.
Scattered moderate to isolated strong convection is noted from 07N
to 17N between 20W and 32W. Scattered moderate convection is
noted from 06N to 13N between 49W and 59W.

GULF OF MEXICO...

Scattered moderate to isolated strong convection is noted over
the eastern Bay of Campeche. Otherwise, a stationary front is
noted just inland of the northern Gulf coast, with a weak pre-
frontal trough noted along 28N from offshore the Florida
Panhandle to the NW Gulf. Scattered moderate to isolated strong
convection 22N and E of 96W. Despite these features, weak high
pressure dominates the basin, providing light and variable winds
and seas of 1 to 2 ft.

For the forecast, the surface trough will continue to support
isolated thunderstorms across the N-central and NE Gulf tonight
and tomorrow. A surface ridge over the central Gulf will support
mostly gentle to moderate winds and slight seas across the basin
through the weekend. Looking ahead, a broad area of low pressure
could form in the central or W Gulf by the beginning of next week.

CARIBBEAN SEA...

Scattered moderate convection is noted near the Windward Islands,
otherwise dry conditions prevail. Fresh to locally strong trades
are noted in the central Caribbean, with moderate winds in the
eastern Caribbean. Gentle winds are noted in the NW basin and S
of the eastern extension of the East Pacific monsoon trough along
10N in the far SW Caribbean. Seas are 5 to 7 ft in the central
Caribbean, and 3 to 5 ft elsewhere, lesser in the lee of Cuba.

For the forecast, fresh to locally strong tradewinds will prevail
across the central Caribbean through tonight. The pressure
gradient between the Bermuda High and the Colombian Low will
loosen by tomorrow morning, resulting in a slight decrease in
winds over the area for the next few days. Gentle to moderate
tradewinds will prevail elsewhere.

ATLANTIC OCEAN...

The dominating feature in the basin is the Bermuda to Azores
ridge. This is leading to mainly gentle E winds N of 25N, with the
gradient between the ridge and the ITCZ and monsoon trough leading
to moderate to fresh trades S of 25N. Some moderate to fresh SW
winds are occurring N of the Bahamas, as an eastward moving front
along the Mid-Atlantic U.S. coast passes N of the waters.
Scattered moderate to isolated strong convection is N of 24N and W
of 70W to the coast of Florida. Some fresh to locally strong
winds have developed within about 100 nm of the center of a 1009
mb low pressure to the SW of the Cabo Verde Islands, that is
depicted in more detail in the tropical waves section above. Other
convection associated with the monsoon trough and tropical waves
is also described in the section above. Seas across the basin are
mainly 5 to 8 ft, with areas NW of a 31N60W to Turks and Caicos
line having somewhat lower seas of 3 to 5 ft.

For the forecast W of 55W, fresh to locally strong tradewinds
will pulse off Hispaniola each evening through the next several
days. Fresh tradewinds will develop south of 25N starting Thu and
diminishing again on Sat. A cold front will approach the NW waters
then stall, but fresh SW winds ahead of the cold front can be
expected Thu and Fri in the NW waters. Gentle to moderate winds
will prevail elsewhere.

$$
AReinhart
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