[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181807
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Sep 18 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
1750 UTC.

...SPECIAL FEATURES...

The center of Hurricane Fiona, at 18/1800 UTC, is near 17.8N
66.9W, or about 40 km to the southwest of Ponce in Puerto Rico.
Fiona is moving WNW, or 285 degrees, 07 knots. The estimated
minimum central pressure is 986 mb. The maximum sustained wind
speeds are 70 knots with gusts to 85 knots. Hurricane force
winds are within 25 nm of the center in the NE quadrant.
Tropical storm force winds are within 110 nm of the center in
the NE quadrant, within 120 nm of the center in the SE quadrant,
within 30 nm of the center in the SW quadrant, and within 80 nm
of the center in the NW quadrant. The sea heights of 12 feet or
greater are within 120 nm of the center in the E semicircle, and
within 60 nm of the center in the W semicircle. The maximum sea
heights are reaching 21 feet. The wind speeds are ranging from
20 knots to 33 knots, and the sea heights are ranging from 9
feet to 12 feet, from 15N to 21N between 63W and 69W, including
in the Mona Passage and in the Atlantic Ocean exposures and
passages. Precipitation: numerous strong is within 135 nm of the
center in the NW quadrant, and within 110 nm of the center in
the NE quadrant. Scattered moderate to widely scattered strong
is within 300 nm of the center in the SE quadrant. 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.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 40W/41W, from 15N
southward, moving westward 15 knots. Precipitation: widely
scattered moderate to isolated strong is from the ITCZ to 13N
between 36W and 47W.

An Atlantic Ocean tropical wave is along 26N50W 07N53W, moving
westward 15 knots. An upper level cyclonic circulation center is
near 24N47W. Upper level cyclonic wind flow covers the Atlantic
Ocean from 18N northward between 36W and 47W. Precipitation:
widely scattered moderate to isolated strong is from 20N
northward between 39W and 53W. Widely scattered moderate to
isolated strong is within 300 nm to the west of the tropical
wave from 11N to 18N. The precipitation pattern is disorganized.
Significant development of this system is becoming less likely,
while it moves generally northward for the next couple of days,
remaining in the central subtropical Atlantic Ocean.
...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of Senegal
near 14N17W, to 10N25W 10N33W. The ITCZ continues from 10N33W to
08N42W and 08N52W. Precipitation: widely scattered moderate to
isolated strong is from 02N to 14N from 60W eastward.

Upper level cyclonic wind flow is from 20N northward from 30W
eastward, and it is digging southward with time. 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...

Middle level to lower level cyclonic wind flow is inland in
Mexico, along a NW-to-SE line. Precipitation: widely scattered
moderate to isolated strong,and some broad surface low pressure,
are in the SW corner of the Gulf of Mexico. The precipitation is
mostly in the coastal waters of Mexico, getting close to the
coastal waters of the Deep South of Texas.

A north-to-south oriented surface trough is between 80W and the
eastern coast of Florida, from the coast of Cuba northward.
Precipitation: isolated moderate to locally strong is from Cuba
northward between the Bahamas and 85W. Scattered moderate to
isolated strong is in the Atlantic Ocean from the NW Bahamas
northward between 72W and the surface trough.

The surface pressure gradient is flat and weak. The sea heights
range from 2 feet to 3 feet, and the wind speeds are gentle or
slower.

High pressure in the southeastern U.S.A. will maintain gentle to
moderate easterly breezes and slight seas during the next few
days.

CARIBBEAN SEA...

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

A weak upper level trough is in the NW corner of the Caribbean
Sea, from the Yucatan Channel to Honduras. The GFS model for 250
mb shows a weak inverted trough, about 630 nm to the southwest
of FIONA. Precipitation: isolated moderate to locally strong is
from 70W westward

The sea heights for the rest of the NE part of the Caribbean
Sea, away from Hurricane Fiona, range from 6 feet to 8 feet. The
sea heights for the SE part of the area range from 2 feet to 4
feet. The sea heights for the remainder of the Caribbean Sea
range from 2 feet to 4 feet. Fresh to strong trade winds have
been off the southern coast of Hispaniola, especially from 15N
northward between 68W and 72W, and at the entrance to the
Windward Passage. Moderate wind speeds or slower are in the
remainder of the area.

The monsoon trough is along 10N/11N, from northern Colombia
beyond southern Nicaragua, into the eastern Pacific Ocean.
Precipitation: isolated moderate is from 15N southward from 70W
westward.

Hurricane Fiona near 17.3N 66.5W 987 mb at 11 AM EDT moving WNW
at 7 kt. Maximum sustained winds 70 kt gusts 85 kt. Fiona will
move to 17.9N 67.3W this evening, 18.9N 68.4W Mon morning,
moving north of Hispaniola near 20.3N 69.3W Mon evening. Fiona
will continue to intensify as is moves more to the north, and
away from the Caribbean Sea. Residual swell from Fiona, that is
in the eastern Caribbean Sea, will subside slowly in that area,
early this week.

ATLANTIC OCEAN...

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

A north-to-south oriented surface trough is between 80W and the
eastern coast of Florida, from the coast of Cuba northward.
Precipitation: isolated moderate to locally strong is from Cuba
northward between the Bahamas and 85W. Scattered moderate to
isolated strong is in the Atlantic Ocean from the NW Bahamas
northward between 72W and the surface trough.

A cold front extends from a 1014 mb low pressure center that is
near 32N61W, to 30N60W 28N65W 29N70W. Precipitation: isolated
moderate to locally strong is from the cold front northward.

Moderate to fresh easterly winds, and sea heights that range
from 3 feet to 5 feet, are from 29N northward from 77W westward.
Fresh to strong trades are between the southeastern Bahamas and
Haiti.

Fresh to strong north to northeast winds, and sea heights that
range from 6 feet to 8 feet, are offshore SW Western Sahara and
Mauritania, primarily from 16N to 22N from 20W eastward.
Moderate wind speeds or slower, and wave heights that range from
3 feet to 6 feet, are in the remainder of the Atlantic Ocean.

Hurricane Fiona near 17.3N 66.5W 987 mb at 11 AM EDT moving WNW
at 7 kt. Maximum sustained winds 70 kt gusts 85 kt. Fiona will
move to 17.9N 67.3W this evening, 18.9N 68.4W Mon morning, 20.3N
69.3W Mon evening, 21.8N 70.1W Tue morning, 23.2N 70.6W Tue
evening, and 24.6N 70.6W Wed morning. Fiona will change little
in intensity as it moves to 28.5N 69.3W early Thu, then it will
move north of the area Thu night. High pressure will build in
the wake of Fiona.

$$
mt/al
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