[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231806
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Sep 23 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 1200 UTC surface analysis and satellite imagery through
1740 UTC.

...SPECIAL FEATURES...

The center of Tropical Storm Ophelia, at 23/1800 UTC,
is near 36.2N 77.3W. Ophelia is about 81 nm/150 km to
the south of Richmond in Virginia; and about 70 nm/
130 km to the ENE of Raleigh in North Carolina.
Ophelia is moving toward the N, or 355 degrees, 11 knots.
The estimated minimum central pressure is 993 mb. The
maximum sustained wind speeds are 35 knots with gusts
to 45 knots. The hazards that will be affecting land are:
the storm surge, wind, rainfall, surf, and tornadoes.
Tropical storm-force winds are: within 280 nm of the
center in the NE quadrant; within 130 nm of the center
in the SE quadrant; within 70 nm of the center in the
SW quadrant; and within 70 nm of the center in the
NW quadrant. Sea heights that are 12 feet or higher
are: 300 nm of the center in the NE quadrant; within
230 nm of the center in the SE quadrant; within 180 nm
of the center in the SW quadrant; and within 0 nm of
the center in the NW quadrant. The maximum sea heights
are 18 feet. Precipitation: widely scattered to
scattered moderate, and isolated strong, is from
20N to 31N between 68W and 81W in the Straits of Florida.
Other precipitation is from 34N northward between
60W and 82W, from South Carolina northward.

Please, read the latest HIGH SEAS FORECAST, that is
issued by the Ocean Prediction Center, at the website-
https://ocean.weather.gov/shtml/NFDHSFAT1.php, and the
latest Ophelia NHC Forecast/Advisory and Public Advisory,
at www.hurricanes.gov, for more details.

The center of Tropical Depression Seventeen, at 23/1500 UTC,
is near 15.6N 38.8W. T.D. Seventeen is moving toward the
W, or 270 degrees, 13 knots. The estimated minimum central
pressure is 1007 mb. The maximum sustained wind speeds
are 30 knots with gusts to 40 knots. Sea heights that are
12 feet or higher are within 120 nm of the center in the
N semicircle. The maximum sea heights are 14 feet. Expect
NE to E winds from 20 knots to 30 knots, and sea heights
from 9 feet to 14 feet in E swell, within 19N38W to 19N39W
to 18N41W to 17N41W to 16N38W to 17N37W to 19N38W. Expect
elsewhere: winds 20 knots or less, and sea heights from
8 feet to 10 feet in NE-to-E swell, within 23N35W to 24N38W
to 21N46W to 15N44W to 14N39W to 16N35W to 23N35W.
Precipitation: scattered to numerous strong is from 14N
to 18N between 32W and 34W. Isolated moderate to locally
strong is from 05N to 21N between 27W and 54W.

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

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 19W/20W, from 20N
southward, moving westward 10 knots to 15 knots.
Precipitation: isolated moderate to locally strong is from
02N to 16N from 30W eastward. The monsoon trough is near
the precipitation also.

A Caribbean Sea tropical wave is along 64W/65W, from 22N
southward, moving westward about 10 knots. Precipitation:
isolated moderate is within 180 nm on either side of the
tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of
Guinea-Bissau near 12N16W, to 10N26W, to 14N34W. The
monsoon trough also is along 14N41W 12N44W. Precipitation:
isolated moderate is in the remainder of the area that is
from 23N southward from 60W eastward.

...GULF OF MEXICO...

A deep layer trough, and a surface trough, and cyclonic
wind flow at many levels of the atmosphere are in the
eastern half of the Gulf of Mexico, and continuing into
the part of the Caribbean Sea that is from 15N northward
from 80W westward. Precipitation: widely scattered moderate
to isolated strong is from 28N southward from 90W eastward.
Mostly moderate to some fresh cyclonic wind flow is in the
eastern half of the Gulf of Mexico. Mostly moderate to
some fresh anticyclonic wind flow is in the western half
of the Gulf of Mexico. The sea heights range from 2 feet
to 3 feet. A maximum of 4 feet is in the east central
Gulf of Mexico.

A surface trough over the southeast Gulf accompanied by
scattered showers and thunderstorms will drift into the
western Gulf through early next week and dissipate.
Meanwhile, weak high pressure will persist over the
north-central and northeast Gulf. This pattern will
support gentle to moderate NE to E winds and slight
seas across the basin through the middle of next week.

...CARIBBEAN SEA...

A deep layer trough, and a surface trough, and cyclonic
wind flow at many levels of the atmosphere are in the
eastern half of the Gulf of Mexico, and continuing into
the part of the Caribbean Sea that is from 15N northward
from 80W westward. Precipitation: isolated moderate to
locally strong is to the northwest of the line that runs
from SE Nicaragua to Puerto Rico.

The sea heights range from 4 feet to 5 feet to the east of
the line that runs from the Windward Passage to the border
of Nicaragua and Costa Rica. The comparatively highest sea
heights range from 6 feet to 7 feet between 74W and 76W
in the Colombia coastal waters. The sea heights range from
1 foot to 2 feet elsewhere. Fresh cyclonic wind flow is from
17N southward between 70W and 80W. Mostly moderate to some
fresh cyclonic wind flow is from 70W eastward. Gentle to
moderate winds are in the rest of the Caribbean Sea.

The monsoon trough is along 10N75W in Colombia, southwestward,
beyond Panama, into the Pacific Ocean. Precipitation: widely
scattered moderate to isolated strong is from 12N southward
from 73W westward.

The 24-hour rainfall totals in inches, for the period
that ended at 23/1200 UTC, according to the MIATPTPAN,
are: 0.76 in Kingston in Jamaica; 0.38 in Guadeloupe;
and 0.19 in Trinidad.

Atlantic high pressure is building into the Bahamas
today in the wake of Ophelia, and will support moderate
to fresh trade winds across most of the eastern and
central Caribbean through early next week, with fresh
to strong pulses off northwest Venezuela and northeast
Colombia during mainly the overnight and early morning
hours. Looking ahead, seas will build in mixed NE and E
swell across waters east of the Leeward Islands starting
early Mon, ahead of newly formed Tropical Depression
Seventeen. Seventeen is expected to turn NW next week
and move into the central Atlantic.

...ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for details about
Tropical Storm Ophelia, and Tropical Depression Seventeen.

A surface trough is along 26N56W 18N61W. Precipitation:
widely scattered moderate to isolated strong is from
18N to 28N between 50W and 62W. Rough seas have been near
this surface trough.

A surface trough is along 31N25W 29N33W 27N41W.
Precipitation: isolated moderate is within 90 nm on
either side of the surface trough, and elsewhere from
24N northward between 20W and 42W.

A dissipating stationary front is along and to the north
of 31N between 45W and 65W. Precipitation: isolated
moderate is from 26N northward between 40W and 68W.

Weak high pressure has been maintaining gentle to moderate
winds, and moderate seas in mixed swell, throughout the
Atlantic Ocean.

Tropical Storm Ophelia is now inland across North Carolina.
Large northerly swell from Ophelia will continue to
impact the waters N of 27N and W of 70W through this evening.
A weak ridge will build in the wake of Ophelia off Florida
through early next week, while a trough will persist across
the Bahamas through Mon. Looking ahead, seas will build in
mixed NE and E swell across waters northeast of the Leeward
Islands starting Mon, ahead of newly formed Tropical Depression
Seventeen. Tropical Depression Seventeen is near 15.6N 38.8W
at 11 AM EDT, moving west at 13 kt. Maximum sustained winds
are 30 kt with gusts to 40 kt. Seventeen is expected to turn
NW by Tue and reach the far southeastern zones on Wed as
a tropical storm.

$$
mt
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