[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 201804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Sep 20 2022

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 Major Hurricane Fiona, at 20/1800 UTC, is near
22.3N 71.7W, or about 50 km/27 nm to the NNE of North Caicos
Island. Fiona is moving NNW, or 330 degrees, 08 knots. The
estimated minimum central pressure is 959 mb. The maximum
sustained wind speeds are 100 knots with gusts to 120 knots.
Hurricane force winds are within 25 nm of the center in the E
semicircle, within 20 nm of the center in the SW quadrant, and
within 25 nm of the center in the NW quadrant. Tropical storm
force winds are within 130 nm of the center in the E semicircle,
within 60 nm of the center in the SW quadrant, and within 100 nm
of the center in the NW quadrant. The sea heights of 12 feet or
greater are within 180 nm of the center in the NE quadrant,
within 120 nm of the center in the SE quadrant, within 90 nm of
the center in the SW quadrant, and within 150 nm of the center
in the NW quadrant. The maximum sea heights are reaching 34
feet. The wind speeds are ranging from 20 knots to 33 knots, and
the sea heights are ranging from 10 feet to 17 feet, elsewhere
in the forecast waters within 180 nm of the center, except for
within 240 nm of the center in the NE quadrant. Expect wind
speeds of 20 knots or less, and sea heights that range from 8
feet to 10 feet in mixed swell, in the remainder of the area
that is from 20N to 25N between 67W and 74W. Precipitation:
numerous strong is within 150 nm of the center in the NE
quadrant, and within 120 nm of the center in the W semicircle.
Scattered moderate to isolated strong is elsewhere within 420 nm
of the center in the NE quadrant, and within 150 nm of the
center in the other quadrants. Isolated moderate to locally
strong is in the Caribbean Sea between 64W and 76W. Please, read
the latest NHC Public Advisory, at
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml, and the
Forecast/Advisory, at
https://www.nhc.noaa.gov/text/MIATCMAT2.shtml, for more details.

The center of Tropical Depression Eight, at 20/1500 UTC, is near
32.8N 45.7W. The Tropical Depression Eight is moving N, or 005
degrees, 09 knots. The estimated minimum central pressure is
1013 mb. The maximum sustained wind speeds are 30 knots with
gusts to 40 knots. Precipitation: scattered to numerous moderate
to strong is within 270 nm of the center in the NE quadrant.
Please, read the latest NHC Public Advisory, at
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml, the Forecast/
Advisory, at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml, and
the High Seas Forecast at
https://ocean.weather.gov/shtml/NFDHSFAT1.php, for more details.

An Atlantic Ocean tropical wave is along 54W/55W, from 14N
southward, moving westward from 10 knots to 15 knots.
Precipitation: scattered moderate to widely scattered strong is
from 13N southward between 50W and 60W. Isolated moderate to
locally strong is from 10N to 19N between 40W and 50W. The
precipitation pattern has become better organized this morning.
Additional development is expected. It is likely for a tropical
depression to form within the next few days, as the system moves
westward to west-northwestward from 15 mph to 20 mph, through
the eastern and central Caribbean Sea. Anyone who has interests
in the Windward Islands should monitor closely the progress of
this system. It is possible that heavy rainfall and gusty winds
may affect these islands beginning on Wednesday. The chance of
formation into a tropical cyclone is medium. Please, refer to
the following website,
https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2, for
more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 62W, from 20N
southward, moving westward from 10 knots to 15 knots.
Precipitation: scattered strong is in Venezuela from 08N to 10N
between the coast and 63W.
Isolated moderate to locally strong is from 13N southward
between the tropical wave and 65W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains border of
Senegal and The Gambia, to 11N20W, to a 1013 mb low pressure
center that is near 09N29W, to 09N36W. The ITCZ continues from
09N36W to 09N40W 08N48W. Precipitation: widely scattered
moderate to isolated strong is from 03N to 16N between 10W and
20W. Isolated moderate to locally strong is in the remainder of
the area that is from the monsoon trough southward between from
42W eastward. Widely scattered moderate to isolated strong is
within 310 nm of the 1012 mb low pressure center in the NW
quadrant.

Upper level cyclonic wind flow is from 20N northward from 30W
eastward. Comparatively drier air in subsidence is apparent in
the water vapor imagery. No significant deep convective
precipitation accompanies the upper level trough.

GULF OF MEXICO...

A north-to-south oriented surface trough is in the eastern Gulf
of Mexico. A second surface trough, along a NW-to-SE line, is in
the SW corner of the Gulf of Mexico. Precipitation: isolated
moderate to locally strong spans the Gulf of Mexico.

A NE-to-SW oriented surface trough extends from a 1013 mb 32N75W
low pressure center, through 31N77W, to 28N81W in Florida, to
23N83W in the Straits of Florida near the coast of NW Cuba.
Precipitation: isolated moderate to locally strong is within 120
nm on either side of the surface trough.

Surface high pressure covers the southern U.S.A. Moderate NE to
E winds are in the eastern and central Gulf of Mexico. The wave
heights range from 2 feet to 4 feet, with the comparatively
highest wave heights in the central sections.

High pressure in the southeastern U.S.A. will maintain gentle to
moderate easterly breezes and slight seas during the next few
days. It is possible that a cold front may reach the NE Gulf of
Mexico on Friday.

CARIBBEAN SEA...

Please, read the SPECIAL FEATURES section, for information about
HURRICANE FIONA.

A weak upper level trough is on top of the Yucatan Peninsula.
Precipitation: isolated moderate is from 15N northward from 80W
westward.

Fresh northeast winds, and wave heights that range from 4 feet
to 5 feet, are in the Windward Passage and in between Jamaica
and Haiti. Moderate SE winds are from 70W eastward. Moderate W
winds are between 70W and 78W. The sea heights range from 5 feet
to 7 feet in the eastern part of the Caribbean Sea, in large
swell that is passing through the Mona Passage. The wave heights
still are
8 feet or higher in the Mona Passage, but they will be subsiding
later today. Gentle to moderate northeast to east winds, and sea
heights that range from 1 foot to 2 feet, are in the NW
Caribbean Sea.

The monsoon trough is along 12N/14N, from 73W beyond Nicaragua,
into the eastern Pacific Ocean. Precipitation: widely scattered
moderate to isolated strong is from 15N southward from 76W
westward.

A 54W/55W Atlantic Ocean tropical wave, still to the east of the
Windward Islands, is expected to move across the Tropical N
Atlantic Ocean from tonight through Wed, across the eastern
Caribbean Sea
Wed night through Thu and across the central Caribbean Sea Fri
through Sat night. This system has become better organized this
morning.  Additional development is expected, and a tropical
depression is likely to form within the next few days as the
system moves westward to west-northwestward at 15 kt  across the
eastern and central Caribbean Sea. Interests in the Windward
Islands should closely monitor the progress of this system as
heavy rainfall and gusty winds could affect these islands
beginning on Wednesday.

ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for information about
Major HURRICANE FIONA.

A NE-to-SW oriented surface trough extends from a 1013 mb 32N75W
low pressure center, through 31N77W, to 28N81W in Florida, to
23N83W in the Straits of Florida near the coast of NW Cuba.
Precipitation: isolated moderate to locally strong is within 120
nm on either side of the surface trough.

The sea heights range from 5 feet to 6 feet from 60W westward.
The sea heights range from 4 feet to 5 feet in the remainder of
the Atlantic Ocean. Mostly moderate and some fresh winds are
from 10N to 20N between 40W and 50W. Gentle to moderate winds
are from 10N to 23N from 40W eastward. Gentle wind speeds or
slower are in the remainder of the Atlantic Ocean.

Major Hurricane Fiona near 22.0N 71.4W 961 mb at 11 AM EDT
moving NNW at 8 kt. Maximum sustained winds 100 kt gusts 120 kt.
Fiona will move to 23.0N 71.7W this evening, 24.4N 71.8W Wed
morning, 26.1N 71.2W Wed evening, 28.3N 70.2W Thu morning, 31.1N
68.4W Thu evening, and 34.7N 65.2W Fri morning. Fiona will
change little in intensity as it moves to near 45.0N 60.0W early
Sat. Swells generated by Fiona are affecting the Virgin Islands,
Puerto Rico, the northern coast of Hispaniola, the Turks and
Caicos Islands, and the southeastern Bahamas. These swells will
continue to spread westward across the southwestern Atlantic
toward the central and northwestern Bahamas and the east coast
of the United States through midweek. Swells from Fiona are
expected to spread across Bermuda later this week. A cold front
will drop south over the northern and central waters Fri through
Sat night followed by fresh northeast winds and building seas.
High pressure will build in behind the cold front.

$$
mt/gr
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