[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192314
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Aug 20 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
2250 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIX: At 19/2100 UTC, Tropical Depression Six
formed at 16.7N 50.2W. Maximum sustained winds are 30 kt with
gusts to 40 kt. The estimated minimum central pressure is 1006 mb.
Numerous moderate isolated strong convection is within 120 nm of
the center. Seas are 8-11 ft within 60 nm of the center. The
depression is moving toward the west- northwest at 14 kt and a
turn to the west is expected later today with a gradual decrease
in forward motion over the next day or so. On Monday, the
depression is expected to turn back to the west- northwest. The
depression is expected to be short- lived and become a remnant low
by Monday.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
Tropical Depression Six NHC Forecast/Advisory and Public Advisory
at www.hurricanes.gov for more details.

Eastern Tropical Atlantic Ocean (AL98): Shower and thunderstorm activity
continues in association with a broad area of low pressure
located several hundred miles west of the Cabo Verde Islands. Seas
are currently 8-12 ft from 16N to 22N between 32W and 40W. Scattered moderate
convection is from 19N to 22N between 34W and 37W. Environmental
conditions appear generally favorable for further development of
this system, and a short-lived tropical depression is likely to
form this weekend while it moves west-northwestward or
northwestward at about 10 mph 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 disturbance has a HIGH chance of formation through 48 hours.

Near the Windward Islands (AL90): A broad area of low pressure
has formed near the Windward Islands, shower and thunderstorm
activity has become better organized since yesterday. Scattered moderate
isolated strong convection is within 60 nm of the coast of Guyana
and Venezuela. Scattered moderate convection is from 11N to 17N
between 64W and 63W. Seas are 8-10 ft from 13N to 18N between 59W
and 62W. Some additional development of this system is likely and
a tropical depression could form by early next week while this
system moves westward to west-northwestward at 10 to 15 mph,
across the Lesser Antilles and over the eastern and central
Caribbean Sea. Regardless of development, heavy rainfall is
possible over portions of the Windward Islands during the next
couple of days. Interests in the eastern and central Caribbean
should monitor the progress of this system. This disturbance has a
MEDIUM chance of formation through 48 hours.

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

...TROPICAL WAVES...

A new tropical wave has just exited the coast of Africa. Its axis
is positioned along 19W. Forward motion is uncertain at this time
since this is the first analysis. Scattered moderate isolated
strong convection is from 10N to 15N east of 26W.

The tropical wave co-located with AL98 is along 36W, from 08N to
22N, and moving westward at 10-15 kt. Scattered moderate
convection is near the northern terminus of the wave axis, from
19N to 22N between 34W and 37W. Seas are currently 8-12 ft from
16N to 22N between 32W and 40W.

The tropical wave co-located with AL90 is approaching the Windward
Islands with its axis along 61W south of 17N. Scattered moderate
isolated strong convection is within 60 nm of the coast of Guyana
and Venezuela. Scattered moderate convection is from 11N to 17N
between 64W and 63W. Seas are 8-10 ft from 13N to 18N between 59W
and 62W.

A large tropical wave is along 83W, from 28N near Tampa Bay south
to 06N in the East Pacific Ocean, moving westward at 10-15 kts.
Scattered showers and tstorms are noted across the Florida
Straits, northern Bahamas, far SE Gulf of Mexico, and the western
Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal border areas
Senegal and Guinea-Bissau near 12N17W to the 17N36W low pressure
center to the 16N48W. The ITCZ is from 15N51W to 13N59W.
Convection is described in TROPICAL WAVES section.

GULF OF MEXICO...

Ahead of the tropical wave described above, a diffuse pressure
gradient is supporting gentle to moderate NE to E winds across the
basin, except offshore the W Yucatan Peninsula where NE winds are
fresh. Seas are 1-3 ft across the basin.

For the forecast, a weak surface ridge over the Gulf waters will
support mostly gentle to moderate winds and slight seas across the
basin through tonight. Looking ahead, an area of disturbed
weather located near the northwestern and central Bahamas is
expected to move into the Gulf of Mexico by early next week, where
a broad area of low pressure is expected to form. Some slow
development of this system is possible thereafter, and a tropical
depression could form as it moves westward and approaches the
western Gulf of Mexico coastline by the middle of next week. This
system has a low chance of development in 48 hours and a medium
chance in the next 7 days.

CARIBBEAN SEA...

The pressure gradient between the subtropical Atlantic ridge and
lower pressure over Colombia and Panama is supporting fresh to
strong E to NE winds in the south-central Caribbean off the coast
of Colombia, where seas are currently 4-6 ft. In the E Caribbean
east of 65W, fresh to strong trades are noted ahead of the
tropical wave associated with AL90, with seas of 6-8 ft.
Elsewhere in the basin, trades are mainly moderate with seas of
3-6 ft. Scattered showers and tstorms are noted near Jamaica and
in the lee of E Cuba.

For the forecast, fresh to strong winds prevail in the eastern
Caribbean as a tropical wave enters the basin with moderate to
fresh winds in the central basin. The tropical wave has a broad
area of low pressure has formed near the Windward Islands, shower
and thunderstorm activity has become better organized since
yesterday. Some additional development of this system is likely
and a tropical depression could form by early next week while this
system moves westward to west- northwestward at 10 to 15 kt,
across the Lesser Antilles and over the eastern and central
Caribbean Sea. Regardless of development, heavy rainfall is
possible over portions of the Windward Islands during the next
couple of days. Interests in the eastern and central Caribbean
should monitor the progress of this system. This system has a
medium chance of development in 48 hours and 7 days. Regardless of
development, strong winds and moderate to rough seas are expected
in the eastern and central basin over the next few days.

ATLANTIC OCEAN...

The subtropical ridge dominates the tropical Atlantic. The
pressure gradient between the ridge and all of our disturbances
to the south is driving a band of fresh to locally strong trades
across the basin from 18N to 25N. North of 25N, trades are mainly
moderate. South of 18N, winds are gentle to moderate from various
directions. Seas are 4-7 ft across the basin.

For the forecast W of 55W, Tropical Depression Six will move to
17.0N 52.6W Sun morning, 17.3N 54.8W Sun afternoon, 17.6N 56.7W
Mon morning, become a remnant low and move to 18.1N 58.6W Mon
afternoon, and dissipate Tue morning. Strong winds and rough seas
are expected with this system as it tracks east of the Lesser
Antilles. Additionally, fresh to strong tradewinds will pulse off
Hispaniola and the Windward Passage each evening into early next
week. Fresh tradewinds south of 25N will persist through the
weekend.

$$
Mahoney
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