[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201037
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...SPECIAL FEATURES...

Tropical Depression Six is centered near 16.8N 52.9W at 20/0900
UTC or 590 nm E of the Northern Leeward Islands, moving W at 13
kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. The low level
circulation is completely exposed due to strong westerly shear
impacting the system and keeping the thunderstorm activity 60 to
90 nm east of the center. The depression will continue west
through Monday, then turn more to the west-northwest. T.D. Six has
likely already peaked, and will likely become post-tropical
remnant low in 36 hours and dissipate by 48 hours if not sooner.

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.

Gale Warning (AL98): A broad area of low pressure located several
hundred miles west-northwest of the Cabo Verde Islands. A 1005 mb
low is analyzed near 19N38W, with tropical wave along 38W.
Scattered moderate convection is from 19N-26N between 34W-39W. A recent
scatterometer satellite pass indicate winds were approaching gale
force within 60 nm on the north side of the low pressure, and a
gale warning is in effect accordingly. Seas are expected to be as
high as 14 ft in the area of strong winds. Environmental
conditions still appear generally favorable for development, and a
short-lived tropical depression is likely to form later today or
tonight while it moves west- northwestward at about 10 kt over the
central tropical Atlantic. By Monday, upper-level winds are
forecast to strengthen over the system, and further development is
not expected. This disturbance has a high chance of formation
through 48 hours.

Eastern Caribbean (AL90): An area of low pressure over the far
eastern Caribbean is producing showers and thunderstorms with
some signs of organization. The low is analyzed near 13N63W, with
tropical wave extending along 63W. Scattered to numerous moderate
convection prevails from 11N-16N between 59W-67W. Seas to 10 ft
are noted in the eastern Caribbean E of 66W. Additional
development of this system is expected, and a tropical depression
is likely to form during the early or middle part of this week.
The system is forecast to move westward at 10 to 15 kt over the
eastern and central Caribbean during the next couple of days, then
turn northward and move over the southwestern Atlantic by
midweek. Regardless of development, heavy rainfall is possible
over portions of the Lesser Antilles 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 extends from 06N to 21N along 21W, moving
west at 10 to 15 kt. Scattered moderate isolated strong convection
is from 08N to 18N and E of 27W. Environmental conditions appear
conducive for gradual development of this system, and a tropical
depression could form later this week while it moves west-
northwestward across the eastern tropical Atlantic.

A western Caribbean tropical wave is evident along 85W south of
22N, moving west at 10 to 15 kt. Scattered moderate convection are
noted W of 82W.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the east Atlantic near 14N17W to AL98.
Other than the convection already discussed in the Special
Features and Tropical Wave sections, no additional significant
convection is noted.

GULF OF MEXICO...

A surface trough is moving across the eastern Gulf enhancing
convection E of 86W. A weak 1015 mb high pressure is evident over
the northwest Gulf near 29N93W. Moderate winds are likely over
the Straits of Florida and the west coast of the Yucatan
peninsula, but otherwise this pattern is supporting light to
gentle breezes and slight seas across the basin.

For the forecast, the 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 over the Straits of Florida and the southern Florida
peninsula will move into the Gulf of Mexico later today, where a
broad area of low pressure is expected to form early this week.
Some slow development of this system could occur thereafter as it
moves westward at about 15 to 20 kt, and a tropical depression
could form as it approaches the western Gulf of Mexico coastline
by Tuesday. This system has a low chance of development in 48
hours and a medium chance in 7 days.

CARIBBEAN SEA...

Refer to the section above for details on AL90, currently located
across the eastern Caribbean.

W of AL90, 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 to 6 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, AL90 could develop into a tropical depression
during the early or middle part of this week. The system is
forecast to move westward at 10 to 15 kt over the eastern and
central Caribbean during the next couple of days, then turn
northward and move over the southwestern Atlantic by midweek.
Regardless of development, heavy rainfall, strong to near gale
winds and moderate to rough seas are possible across the eastern
Caribbean during the next couple of days. This system has a medium
chance of development in 48 hours and a high chance in 7 days.

ATLANTIC OCEAN...

Refer to the sections above for details TD Six, invests, and
tropical waves moving across the basin.

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. Farther south, winds are gentle to moderate from
various directions. Seas are 4-7 ft across the basin.

For the forecast west of 55W, TD Six will move to 17.0N 54.8W
this afternoon, become a remnant low and move to 17.3N 56.8W Mon
morning, and dissipate Mon afternoon. 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.

$$
ERA
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