[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221802
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Thu Sep 22 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 22/1800 UTC, is near
29.7N 69.8W. Fiona also is about 555 km/300 nm to the WSW of
Bermuda. Fiona is moving NNE, or 025 degrees, 13 knots. The
estimated minimum central pressure is 936 mb. The maximum
sustained wind speeds are 115 knots with gusts to 140 knots.
Hurricane force winds are within 55 nm of the center in the NE
semicircle, within 60 nm of the center in the SE quadrant,
within 45 nm of the center in the SW quadrant, and within 45 nm
of the center in the NW quadrant. Tropical storm force winds are
within 150 nm of the center in the NE quadrant, within 180 nm of
the center in the SE quadrant,  within 130 nm of the center in
the SW quadrant, and within 150 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 270 nm of the center
in the SE quadrant, within 270 nm of the center in the SW
quadrant, and within 240 nm of the center in the NW quadrant.
The maximum sea heights are reaching 50 feet. The wind speeds in
the forecast waters are ranging from 20 knots to 33 knots within
240 nm of the center, except within 360 nm of the center in the
SE quadrant. The sea heights range from 8 feet to 12 feet in
mixed swell from 21N northward between 64W and 80W, from the
Bahamas eastward. Precipitation: numerous strong is within 200
nm of the center in the NE quadrant. Broken to overcast
multilayered clouds, and scattered moderate to strong, are
within 480 nm of the center in the NE quadrant. Isolated
moderate to locally strong is in the remainder of the Atlantic
Ocean from 20N northward from 60W westward. 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 22/1500 UTC, is near
40.9N 33.8W. Gaston is moving ENE, or 065 degrees, 18 knots. The
estimated minimum central pressure is 999 mb. The maximum
sustained wind speeds are 55 knots with gusts to 65 knots.
Precipitation: scattered moderate to strong is within 180 nm of
the center in the NE quadrant. Please, read the latest NHC
Public Advisory, at
https://www.nhc.noaa.gov/text/MIATCPAT3.shtml, the Forecast/
Advisory, at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml, and
the High Seas Forecast at
https://ocean.weather.gov/shtml/NFDHSFAT1.php, for more details.

A tropical wave is along 65W in the southeastern Caribbean Sea.
A 1008 mb low pressure center is near 11.5N along the tropical
wave. Precipitation: scattered moderate to widely scattered
strong is from 16N southward between 62W and 73W. The
environment is forecast to become gradually more favorable in a
couple of days, although upper level winds currently are
inhibiting development. It is likely for a tropical depression
to form in a couple of days. The disturbance is forecast to move
west-northwestward through the eastern Caribbean Sea during the
next day or two, and be in the central Caribbean Sea this
weekend. It is likely for locally heavy rainfall and gusty winds
to affect the Windward Islands, northern Venezuela, and the ABC
island chain today. It is likely for these impacts to spread to
northeastern Colombia later this evening. The chance of
formation into a tropical cyclone during the next 48 hours is
high.

A tropical wave is along 16W near the western coast of Africa. A
1008 mb low pressure center is near 15N along the tropical wave.
Precipitation: widely scattered moderate to isolated strong is
from 10N to 18N between 12W and 20W. The environmental
conditions are forecast to be conducive for some development. It
is possible that a tropical depression may form by this weekend.
The system is forecast to move northward slowly, between west
Africa and the Cabo Verde Islands. The chance of formation into
a tropical cyclone during the next 48 hours is medium.

Please, refer to the following website,
https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2, for
more details.

...TROPICAL WAVES...

Please, read the SPECIAL FEATURES section, for information about
the tropical waves.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the combination 16W tropical
wave, and the 1008 mb low pressure center that is near 15N along
the tropical wave, to a second 1008 mb low pressure center that
is near 12N35W, to 09N38W. The ITCZ continues from 09N38W to
06N57W, to Guyana near 05N59W.
Precipitation: widely scattered moderate to isolated strong is
from the monsoon trough/ITCZ southward from 40W eastward.
Isolated moderate is from the ITCZ to 17N between 40W and 50W.
Precipitation with the 12N35W low pressure center: widely
scattered moderate to isolated strong is from 08N to 16N between
30W and 40W. Some slow development of this system is possible
during the next several days, despite marginal environmental
conditions. The forecast is for this feature to move
northwestward or northward, slowly, in the tropical Atlantic
Ocean.

GULF OF MEXICO...

Broad surface anticyclonic wind flow is in the SE U.S.A., and in
south Texas, into south central Mexico. A surface trough extends
from NE Mexico, to the Yucatan Peninsula, into the NW corner of
the  Caribbean Sea. The GFS model for 250 mb, for 500 mb, and
for 700 mb shows broad cyclonic wind flow/a trough, that covers
the areas from the Yucatan Channel into the SW corner of the
Gulf of Mexico. Broad upper level anticyclonic wind flow covers
the northern half of the Gulf of Mexico, away from the cyclonic
wind flow. Precipitation: isolated moderate to locally strong
spans the entire area.

Gentle to locally moderate N to NE winds are in the northern
half, and in the far SW Gulf. Light to gentle winds are
elsewhere. The sea heights range from 2 feet to 4 feet.

A relatively weak pressure gradient in the Gulf waters will
support mainly gentle to locally moderate winds and slight seas
through the upcoming weekend. A weak cold front will reach the
the NE waters on Fri. On Mon, wind and seas could begin to
increase across the Yucatan Channel as a possible tropical
cyclone approaches from the NW Caribbean.

CARIBBEAN SEA...

Please, read the SPECIAL FEATURES section, for more information
about the 65W tropical wave, and the 1008 mb low pressure center
that is along the tropical wave. The chance of development into
a tropical cyclone during the next 48 hours is high.

A surface trough extends from the NW Caribbean Sea, beyond the
Yucatan Peninsula, to NE Mexico. Precipitation: isolated
moderate is from 15N northward from 80W westward. Most of the
precipitation covers the areas that are from western Honduras to
Belize to the SE Yucatan Peninsula.

Light to gentle variable winds, and sea heights that range from
1 foot to 3 feet, are in the remainder of the basin, from 68W
westward.

The monsoon trough is along 18N80W, through Honduras, and beyond
El Salvador, into the eastern Pacific Ocean. Precipitation:
widely scattered moderate to isolated strong is from 14N
southward from 72W westward.

An eastern Caribbean Sea tropical wave is near 65W. A low
pressure of 1008 mb is along the wave near 11.5N65W. The
environment is forecast to become gradually more favorable in a
couple of days, although upper-level winds currently are
inhibiting development. It is likely for a tropical depression
to form in a couple of days. The disturbance is forecast to move
west-northwestward through the eastern Caribbean Sea during the
next day or two, and be in the central Caribbean Sea this
weekend.

ATLANTIC OCEAN...

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

An upper level trough passes through 31N43W, to a cyclonic
circulation center that is near 20N51W, to the coastal border
areas of Venezuela and Guyana along 60W. Precipitation:
scattered moderate to widely scattered strong is in the coastal
plains and the coastal waters between 56W Suriname and 64W
Venezuela. Widely scattered moderate to isolated strong is from
09N to 13N between 50W and 60W.

A surface ridge extends from a 1025 mb high pressure center that
is near 35N27W, through 31N43W, 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 mainly easterly moderate, with sea heights
reaching 6 feet at a maximum. The exception is fresh to locally
strong N to NE winds, and the sea heights reaching 8 feet,
between the Cabo Verde Islands and W Africa.

Hurricane Fiona near 28.6N 70.2W 936 mb at 11 AM EDT moving NNE
at 13 kt. Maximum sustained winds 115 kt gusts 140 kt. Fiona
will move to 30.7N 68.8W this evening, be N of the area near
34.6N 65.2W Fri morning, 40.6N 61.8W Fri evening, become
extratropical and move to 45.5N 61.2W Sat morning. Swells
generated by Fiona will continue to spread northwestward across
the western Atlantic Ocean toward the mid-Atlantic and northeast
coasts of the United States during the next day or so. The
swells will also reach Atlantic Canada on Friday. These swells
are likely to cause life-threatening surf and rip current
conditions. A cold front will drop south into the north waters
early on 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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