[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 211758 AAA
TWDAT

Tropical Weather Discussion....Update
NWS National Hurricane Center Miami FL
1805 UTC Wed Sep 21 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
1700 UTC.

Updated information on Hurricane Fiona and the Tropical Waves
section

...SPECIAL FEATURES...

The center of Major Hurricane Fiona at 21/1800 UTC, is near 25.1N
71.7W or 565 nm SW of Bermuda. Fiona is moving north at 07 knots.
The estimated minimum central pressure is 937 mb. The maximum
sustained wind speeds are 115 knots with gusts to 140 knots.
Hurricane force winds are within 40 nm of the center in the NE
semicircle, within 30 nm of the center in the SE quadrant, within
20 nm of the center in the SW quadrant, and within 30 nm of the
center in the NW quadrant. Tropical storm force winds are within
140 nm of the center in the NE quadrant, within 130 nm of the
center in the SE quadrant, within 80 nm of the center in the SW
quadrant, and within 120 nm of the center in the NW quadrant. The
sea heights of 12 feet or greater are within 240 nm of the center
in the NE quadrant, within 180 nm of the center in the SE
quadrant, within 150 nm of the center in the SW quadrant, and
within 210 nm of the center in the NW quadrant. The maximum sea
heights are reaching 38 feet. The wind speeds are ranging from 20
knots to 33 knots within 270 nm E semicircle and within 150 nm W
semicircle of the center. The sea heights are ranging from 8 feet
to 12 feet in mixed swell, from 21N to 30N between 66W and 77W and
to the east of the Bahamas. Numerous strong convection is within
90 nm of the center. Scattered moderate to strong convection is
within 400 nm of the center in the NE semicircle. quadrant, and
within 120 nm of the center in the W semicircle. Scattered
moderate to isolated strong convection 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
convection is in the Caribbean Sea and in the Atlantic Ocean in
the remainder of the areas that are from 16N northward between 60W
and 77W. 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 Storm Gaston, at 21/1500 UTC, is near
38.3N 41.3W or 675 nm W of the Azores. Gaston is moving NE at 14
knots. The estimated minimum central pressure is 1000 mb. The
maximum sustained wind speeds are 55 knots with gusts to 65 knots.
Precipitation: scattered moderate to strong is within 120 nm of
the center in the NE quadrant. Isolated moderate to locally strong
is elsewhere within 360 nm of the center in the E semicircle.
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 59W, from 15N
southward, moving westward at 10 to 15 knots. Scattered moderate
to widely scattered strong convection is from 07N to 14N between
55W and 68W. This area covers parts of the Atlantic Ocean, inland
areas and the coastal plains of Guyana and Venezuela, and the SE
Caribbean Sea. The feature continues to show signs of
organization. It is likely for a tropical depression to form
within the next few days. The weather system will be moving west-
northwestward, across the southern Windward Islands, today, and
then toward the central Caribbean Sea later this week. Anyone who
has interests in the Windward Islands should monitor closely the
progress of this system. Heavy rainfall and gusty winds are
affecting these islands. Heavy rainfall is forecast to affect
northwestern Venezuela, northeastern Colombia, and the ABC island
chain later this week. The chance of formation into a tropical
cyclone is high. Please, refer to the following website,
https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2, for more
details.

...TROPICAL WAVES...

A central Atlantic tropical wave is near 32W from west of the Cabo
Verde Islands at 16N southward through a weak 1012 mb low at
10.5N32.5W, and moving west at 5 to 10 kt. Scattered moderate to
isolated strong convection is present from 09N to 14N between 30W
and 36W. Slow development is possible and there is a low chance of
formation for the next 5 days.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains border of
Senegal and The Gambia, to 11N20W, to a 1012 mb low pressure
center that is near 11N32W, to 09N38W. The ITCZ continues from
09N38W to 10N44W 11N50W. Precipitation: scattered moderate to
strong is within 200 nm of the 1012 mb low pressure center in
the N quadrant. Isolated moderate to locally strong is within
200 nm of the center in the W quadrant. Isolated moderate to
locally strong is from 03N to 16N from 55W eastward.
Slow development of the 1012 mb low pressure center is possible
during the next several days, despite a dry environment. The low
pressure center is forecast to move northwestward, and then
westward, in the tropical Atlantic Ocean.

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 NE-to-SW 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 is from 28N southward.

Moderate NE winds, and sea heights that range from 3 feet to 5
feet, are in the central Gulf of Mexico. Gentle winds, and sea
heights that range from 1 foot to 3 feet, are in the remainder
of the
Gulf of Mexico.

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

...CARIBBEAN SEA...

A surface trough extends from 17N80W, beyond the Yucatan
Peninsula, into the SW Gulf of Mexico.
Precipitation: isolated moderate is from 15N northward from
Jamaica westward.

Gentle winds cover most of the Caribbean Sea. An exception is
for moderate S winds from 15N northward between 66W and 71W,
including in the Mona Passage. The sea heights range from 3 feet
to 5 feet in the eastern Caribbean Sea. The sea heights range
from 1 foot to 3 feet in the western Caribbean Sea.

The monsoon trough is along 12N/13N, from 77W beyond Nicaragua,
into the eastern Pacific Ocean. Precipitation: isolated moderate
to locally strong is from 16N southward from 73W westward.

A tropical wave is currently located east of the Windward
Islands near 59W or couple hundred miles east of the southern
Windward Islands. The system continues to show signs of
organization, and it will likely become a tropical depression
within the next couple of days. The disturbance is forecast to
move west-northwestward across the southern Windward Islands
today and then move toward the central Caribbean Sea later this
week. Interests in the Windward Islands should closely monitor
the
progress of this system as heavy rainfall and gusty winds are
affecting these islands. Regardless of development, heavy
rainfall is forecast to affect northwestern Venezuela,
northeastern Colombia, and the ABC island chain later this week.

...ATLANTIC OCEAN...

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

A 1025 mb high pressure center is near 37N27W. A surface ridge
extends from a 1025 mb high pressure center that is near 37N27W,
through 31N42W, to 25N60W. Isolated moderate to locally strong
is from 20N northward between 44W and 60W. This precipitation is
downstream from a frontal boundary that is from 30N northward
between 50W and 72W.

The wind speeds are gentle to moderate, and the sea heights
range from 3 feet to 5 feet, from 20N northward between 20W and
62W.

Major Hurricane Fiona near 24.6N 71.7W 937 mb at 11 AM EDT
moving N at 7 kt. Maximum sustained winds 115 kt gusts 140 kt.
Fiona will move to 25.8N 71.4W this evening, 28.0N 70.5W Thu
morning, 30.7N 68.9W Thu evening, 34.4N 65.4W Fri morning, 39.7N
61.8W Fri evening, and become extratropical and move to 45.3N
60.6W Sat morning. Fiona will weaken as an extratropical cyclone
near 51.5N 60.0W early Sun. Swells generated by Fiona will
continue to spread westward across the southwestern Atlantic
toward the northwestern Bahamas and the east coast of the United
States during the next day or two. Swells from Fiona are
expected to reach Bermuda by late tonight. The swells could
cause life-threatening surf and rip current conditions. A cold
front will move southward into the north waters Fri through Sat
night followed by fresh northeast winds and building seas. High
pressure will build in behind the cold front.

$$

MT/GR/PC
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