[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170604
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sun Sep 17 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 0000 UTC surface analysis and satellite imagery through
0540 UTC.

...SPECIAL FEATURES...

The center of Post-Tropical Cyclone Lee, at 17/0600 UTC,
is near 45.9N 64.8W. Lee is about 8 nm/15 km to the
SW of Moncton in New Brunswick. Lee is moving toward
the NNE, or 030 degrees, 12 knots. The estimated minimum
central pressure is 983 mb. The maximum sustained wind
speeds are 50 knots with gusts to 60 knots. The hazards
that will be affecting land are: wind, surf, rainfall,
and the storm surge. Tropical storm-force winds are:
within 190 nm of the center in the NE quadrant; within
250 nm of the center in the SE quadrant; within 120 nm
of the center in the SW quadrant; and within 80 nm of
the center in the NW quadrant. Sea heights that are
12 feet or higher are: 480 nm of the center in the
NE quadrant; within 660 nm of the center in the
SE quadrant; within 570 nm of the center in the
SW quadrant; and within 0 nm of the center in the
NW quadrant. The maximum sea heights are 36 feet.
All the precipitation is from 36N northward from
70W westward. A frontal boundary passes through
Bermuda, beyond SE coastal Georgia. Precipitation:
isolated moderate to locally strong is
from 20N northward from 60W westward.

The center of Tropical Storm Margot, at 17/0300 UTC, is
near 33.9N 40.5W. Margot is moving toward the W, or
260 degrees, 07 knots. The estimated minimum central
pressure is 999 mb. The maximum sustained wind speeds
are 40 knots with gusts to 50 knots. Tropical storm-force
winds are: within 160 nm of the center in the NE quadrant;
within 90 nm of the center in the SE quadrant; within
70 nm of the center in the SW quadrant; and within
160 nm of the center in the NW quadrant. The radius of
the sea heights that are 12 feet or greater is:
within 330 nm of the center in the NE quadrant; within
210 nm of the center in the SE quadrant; within 270 nm
of the center in the SW quadrant; and within 360 nm of
the center in the NW quadrant. The maximum sea heights
are 20 feet. Swells, that are being generated by Margot,
will continue to affect the Azores for the next several
days. It is likely for the swells to cause life-threatening
surf and rip current conditions. Please, consult bulletins
and charts from your local weather bureau office. Gradual
weakening is forecast during the next couple of days.
Slight fluctuations in intensity are possible. The deep
convective precipitation that was associated with Margot
has dissipated.

The center of Tropical Storm Nigel, at 17/0300 UTC,
is near 22.0N 48.0W. Nigel is moving toward the NW, or
325 degrees, 14 knots. The estimated minimum central
pressure is 1005 mb. The maximum sustained wind speeds
are 35 knots with gusts to 45 knots. Tropical storm-force
winds are: within 80 nm of the center in the NE quadrant;
within 0 nm of the center in the SE quadrant; within
0 nm of the center in the SW quadrant; and within
60 nm of the center in the NW quadrant. The radius of
the sea heights that are 12 feet or greater is:
within 120 nm of the center in the NE quadrant; within
60 nm of the center in the SE quadrant; within 60 nm
of the center in the SW quadrant; and within 90 nm of
the center in the NW quadrant. The maximum sea heights
are 14 feet. Expect E winds 20 knots to 33 knots, and
sea heights from 11 feet to 13 feet within 23N47W to
24N49W to 23N49W to 22N49W to 21N49W to 22N47W to 23N47W.
Expect also winds 20 knots or less, and sea heights from
8 feet to 10 feet in mixed swell, within 25N42W to 28N49W
to 25N52W to 19N51W to 18N47W to 20N42W to 25N42W.
Precipitation: scattered to numerous strong is within
240 nm of the center in the NE semicircle. Isolated
moderate to locally strong is in the remainder of the
area that is from 20N southward between 40W and 58W.

Please, visit www.hurricanes.gov, for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 34W/35W, from 12N
southward, moving westward 10 knots to 15 knots.
Precipitation: widely scattered to isolated strong is
within 300 nm on either side of the monsoon trough/ITCZ,
from 44W eastward, including within 360 nm to the west
of the tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal border of
Senegal and Guinea-Bissau, to 09N20W and 07N32W. The ITCZ
is along 04N/05N between 35W and 43W. Precipitation:
widely scattered to isolated strong is within 300 nm on
either side of the monsoon trough/ITCZ, from 44W eastward,
including within 360 nm to the west of the tropical wave.
isolated moderate to locally strong is in the remainder of the
area that is from 20N southward from 60W eastward.

...GULF OF MEXICO...

A weak inland stationary front passes through the U.S.A.
coastal plains, from SE Georgia, to the upper Texas Gulf
coast, and to south Texas. Precipitation: isolated
moderate to locally strong is from 90W westward.

An inland surface trough passes through southern Mexico,
through the Isthmus of Tehuantepec, to the Yucatan
Peninsula. Precipitation: isolated moderate to locally
strong is within 90 nm on either side of the surface trough.

One surface ridge passes through south central Georgia,
through parts of Florida, toward the Yucatan Peninsula.
A second surface ridge passes through the deep South of
Texas, toward the Isthmus of Tehuantepec of southern
Mexico. Weak upper level cyclonic wind flow spans the area.
Precipitation: isolated moderate to locally strong is from
90W eastward.

Light to gentle winds, and sea heights that range from
1 foot to 2 feet, cover most of the area. An exception is
for mostly moderate to some fresh NE winds that are from
23N southward between 88W and 94W, on the NW and W side
of the Yucatan Peninsula.

A weak ridge across the central Gulf will dominate the
basin through early Sun, supporting mainly light to gentle
anticyclonic winds along with slight seas. A weak cold
front is forecast to move off New Orleans and Mississippi
into the N-central and NE Gulf Sun followed by N to NW
moderate winds and isolated to scattered showers. The
front is forecast to move E of the area by Sun night,
with a reinforcing front Mon. A weak surface ridge will
develop afterward, supporting gentle to moderate
NE to E winds through Wed, freshening in the NE Gulf Thu.
Otherwise, winds will pulse to moderate to fresh W-NW of
the Yucatan Peninsula this evening and Sun evening.

...CARIBBEAN SEA...

Mostly moderate and some fresh NE winds are in the eastern
one-third of the area. Mostly fresh to some strong NE winds
are from 16N southward between 70W and 78W. Moderate NE winds
are in the remainder of the area that is between 70W and 80W.
Gentle to moderate winds are in the rest of the Caribbean Sea.
The sea heights: are reaching 5 feet from the coastal waters
of SW Haiti to the coast of Colombia; range from 3 feet to
4 feet elsewhere from 80W eastward; 2 feet from 15N southward
from 80W westward; 1 foot elsewhere.

The monsoon trough is along 10N/11N from 73W in Colombia
beyond Costa Rica. Precipitation: widely scattered moderate
to isolated strong is from 13N southward from 80W westward.

An upper level cyclonic circulation center is on top of
Jamaica. Upper level cyclonic wind flow is from 70W westward.
Precipitation: isolated moderate is elsewhere from 70W
westward.

The 24-hour rainfall totals in inches, for the period
that ended at 17/0000 UTC, according to the MIATPTPAN,
are: 0.98 in Guadeloupe.

Northerly swell affecting the NE Caribbean Passages
will gradually subside tonight, then is forecast to build
again slightly there Sun night through Wed due to Tropical
Storm Nigel, which is forecast to remain well NE of the
area while strengthening. Otherwise, moderate to fresh
trades will prevail across the Central Caribbean, locally
fresh to strong off Colombia, while gentle to moderate
winds will dominate elsewhere through the forecast period.

...ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for details
about Post-Tropical Cyclone Lee, Tropical Storm Margot,
and Tropical Storm Nigel.

An upper level cyclonic circulation center is near 26N58W.
Precipitation: isolated moderate to locally strong is
elsewhere from 20N northward between 50W and 60W, and
away from T.S. Nigel.

A cold front passes through 31N10W, to just to the south
of the Canary Islands, beyond 31N29W. The sea heights are
8 feet and higher, from 30N20W northwestward. Fresh NE winds
are to the north of the cold front. Mostly moderate to some
fresh NE winds are elsewhere from 10N northward from 35W
eastward. Precipitation: isolated moderate is from 20N
northward from 40W eastward.

Moderate or slower winds, and sea heights that range from
4 feet to 7 feet, are in the remainder of the Atlantic Ocean.

Tropical Storm Nigel is near 22.0N 48.0W at 11 PM EDT, and
is moving northwest at 14 kt. Maximum sustained winds are
35 kt with gusts to 45 kt, and the minimum central pressure
is 1005 mb. Nigel will move to 23.6N 49.2W Sun morning,
25.3N 50.6W Sun evening, strengthen to a hurricane near
26.7N 52.2W Mon morning, 27.8N 54.0W Mon evening, 29.4N 55.7W
Tue morning, and 31.3N 56.7W Tue evening. Nigel will change
little in intensity as it moves near 36.0N 55.6W late Wed.
Otherwise, high pres will prevail across the waters through
Sun. A weak cold front is forecast to move off the SE U.S.
coast early on Mon with new high pres building down behind
it. The front may stall and linger along 27N/28N through
mid-week.

$$
mt
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