[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180958
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Fri Aug 18 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 0600 UTC surface analysis and satellite imagery through
0940 UTC.

...SPECIAL FEATURES...

Eastern Tropical Atlantic (AL98):
Showers and thunderstorms continue to show some signs of
organization in association with a broad area of 1009 mb low
pressure located a few hundred miles west of the Cabo Verde
Islands near 16N31W. Environmental conditions appear generally
favorable for additional development of this system, and a
tropical depression is likely to form over the weekend while it
moves toward the west- northwest or northwest at about 5 to 10 kt
across the eastern tropical Atlantic. By early next week, upper-
level winds over the system are forecast to increase, and further
development is not expected. This system has a medium chance of
tropical cyclone development within 48 hours.

Central Tropical Atlantic (AL99):
An elongated trough of 1009 mb low pressure located more than 1000
miles west-southwest of the Cabo Verde Islands near 13N42W is
producing some disorganized showers and thunderstorms.
Environmental conditions are only marginally conducive for further
development of this system, but a tropical depression could still
form during the next couple of days while it moves west-
northwestward at 10 to 15 kt across the central tropical
Atlantic. Thereafter, upper- level winds are forecast to become
unfavorable for any further development. This system has a medium
chance of tropical cyclone development within 48 hours.

Please refer to the latest NHC Tropical Weather Outlook at
www.hurricanes.gov for more details on both special features.

...TROPICAL WAVES...

A tropical wave is along 31N through the low pressure mentioned in
the Special Features section, moving west with the low pressure at
5 to 10 kt. Scattered moderate convection is evident from 90 to
180 nm in the northwest quadrant of the low, and from 09N to 12N
between 32W and 35W.

A western Atlantic tropical wave has its axis near 52W from 06N
to 19N. It is moving westward near 15 kt. Scattered moderate and
isolated strong convection is depicted from 10N to 13N between
50W and 55W.

A Caribbean tropical wave has its axis near 75W, or from the
western part of Haiti to just inland Colombia, moving west at 10
to 15 kt. No significant convection is evident at this time.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis enters the Atlantic near 19N16W to the low
pressure mentioned in the Special Features section near 16N31N to
the other low pressure mentioned in the Special Features section
near 13N42W, then farther west to 11N55W. Scattered moderate to
isolated strong convection is noted from 12N to 14N between 42W
and 48W.

GULF OF MEXICO...

A weak pressure pattern extending across the basin is supporting
light to gentle breezes and slight seas this morning, except for
moderate winds off the western Yucatan peninsula.

For the forecast, the surface ridge over the Gulf waters will
support mostly gentle to moderate winds and slight seas across the
basin through Sat night. Looking ahead, a surface trough is
expected to move across the Gulf from east to west Sun through
early next week. The trough could form into a broad area of low
pressure in the central or W Gulf by the beginning of next week.
Some slow development of this system is possible thereafter as it
moves westward and approaches the western Gulf of Mexico coastline
by the middle of next week.

CARIBBEAN SEA...

Fresh NE to E winds are converging over the northeast Caribbean
and supporting scattered showers and a few thunderstorms over the
region. Wave heights are 5 to 7 ft, although maybe near 8 ft in
Atlantic passages due to easterly swell. Fresh winds are noted
over the Gulf of Venezuela, off central Colombia, and the Gulf of
Honduras, with 4 to 6 ft seas. Gentle to moderate trade winds and
3 to 5 ft seas are noted elsewhere. A few showers and
thunderstorms are evident are noted over the Windward Passage and
off western Cuba.

For the forecast, moderate to fresh trade winds will prevail over
the eastern and central Caribbean during the next few days. A
strong tropical wave is likely to approach the E Caribbean this
weekend and spread fresh to strong winds and building seas over
the NE Caribbean Sat night into Tue.

ATLANTIC OCEAN...

Please refer to the SPECIAL FEATURES and the MONSOON TROUGH/ITCZ
sections above for details on the two low pressure systems in
the central and eastern Atlantic that could become tropical
cyclones and convection in the tropical Atlantic.

The subtropical ridge extends from 1024 mb high pressure northeast
of Bermuda to the east-central Florida coast. This pattern is
supporting moderate to fresh easterly flow south of 25N with 5 to
7 ft combined seas east of 50W and 6 to 9 ft combined seas over
open waters west of 50W with a component of easterly swell. Gentle
breezes are noted north of 25N, except moderate SW flow off the
northeast coast of Florida.

For the forecast west of 55W, fresh to locally strong tradewinds
will pulse off Hispaniola each evening into early next week. Fresh
tradewinds south of 25N will persist through Sat. A strong
tropical wave could enhance winds and seas near the Leeward and
Virgin Islands over the weekend, and north of Puerto Rico early
next week.

$$
Christensen
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