[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080558
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Sep 8 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
0500 UTC.

...SPECIAL FEATURES...

Major Category Five Hurricane Lee is centered near 17.3N 52.4W at
08/0300 UTC or 610 nm east of the Northern Leeward Islands, and
moving WNW at 12 kt. Estimated minimum central pressure is 928
mb. Maximum sustained winds are 140 kt with gusts to 170 kt. Peak
seas near the center are from 27 to 29 ft. Seas 12 ft or greater
extend outward from the center up to 210 nm NE quadrant, 150 nm NE
and SE quadrants, and 90 nm SW quadrant. Numerous scattered to
isolated strong convection are seen up to 70 nm in a NW
semicircle, and 100 nm in a SE semicircle. Lee is forecast to
maintain its WNW movement through early next week with a
significant decrease in forward speed by Sat. while gradually
slowing down its forward speed. Lee is expected to pass well north
of the Virgin and northern Leeward Islands, and Puerto Rico near
Sun. Additional strengthening is expected overnight, then follows
by some fluctuations in intensity afterward but Lee is forecast to
remain a major hurricane through early next week. Large swells
generated by Lee should reach the Leeward Islands by Fri night,
and the Virgin Islands, Puerto Rico and Hispaniola this weekend,
and finally the Bahamas and Bermuda by Mon. Long- period swell
well west and northwest of Lee are likely to cause dangerous surf
and rip currents along most of the U.S. East Coast beginning Sun.
Please consult products from your local forecast weather office.

Tropical Storm Margot is centered near 16.8N 29.3W at 08/0300 UTC
or 310 nm west of the Cabo Verde Islands, and moving WNW at 14
kt. Estimated minimum central pressure is 1004 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are
from 28 to 30 ft near the center with seas 12 ft or greater
extending outward up to 30 nm in a northern semicircle. Scattered
moderate convection are found near the center and up to 170 nm in
a northern semicircle. Margot is forecast to maintain its current
motion through this weekend, then turn toward the northwest early
next week. A gradual strengthening trend is anticipated for the
next few days, and Margot could become a hurricane over the
weekend.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml
and the latest NHC Forecast/Advisory and Public Advisory on Lee
and Margot at www.hurricanes.gov for more details.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic near the Mauritania/Senegal
border and extends southwestward to 14N19W, then continues from
10N30W to 06N39W. Scattered showers and isolated thunderstorms are
occurring near the first segment from 10N to 20N between
Mauritania-Senegal coast and 20W. Widely scattered moderate
convection is noted near and south of the second segment from 2N
to 8N between 30W and 37W. There is no ITCZ present based on the
latest analysis.

The eastern end of the East Pacific monsoon trough is triggering
scattered showers and isolated thunderstorms over the Caribbean
waters near Costa Rica and Panama.

...GULF OF MEXICO...

A surface trough curves southeastward from just southwest of New
Orleans to the east-central Gulf. Scattered showers and
thunderstorms are present near the Louisiana coast. Otherwise, a
modest surface ridge related to a 1012 mb high at the northwestern
Gulf dominate much of the Gulf. Light to gentle winds and 1 to 2
ft seas are evident across the central and eastern Gulf, including
the Yucatan Channel. Gentle to locally moderate E to SE winds with
seas at 2 to 3 ft prevail at the western Gulf.

For the forecast, the high and associated surface ridge will
continue to dominate the region with light to moderate winds
through midweek next week.

...CARIBBEAN SEA...

A broad upper-level trough over central Cuba is inducing scattered
moderate convection at the northwest basin, and near Hispaniola
and Puerto Rico. A modest trade-wind regime are present across
much of the basin. Moderate to fresh ENE to E winds and seas of 5
to 7 ft are noted at the south-central basin. Gentle to moderate
NE to E winds with 3 to 5 ft seas are evident at the eastern,
north-central and southwestern basin, except near Costa Rica and
Panama where light to gentle winds and 4 to 5 ft seas in moderate
easterly swell are present. Gentle to moderate E winds and seas at
2 to 4 ft prevail at the northwestern basin.

For the forecast, Hurricane Lee is expected to strengthen further
through Fri morning, and move to near 18.1N 54.0W Fri morning and
near 19.1N 56.1W Fri evening. It will reach near 20.1N 58.0W Sat
morning, 20.9N 59.6W Sat evening, 21.5N 60.9W Sun morning and
22.1N 62.2W Sun evening. In the Caribbean, moderate to fresh
trade winds will continue in the central and eastern basin into
the weekend. Large E to NE swell produced by Lee will reach the
passages of the northeastern Caribbean early Sat, then the Mona
Passage Sun night.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section at the beginning for
information about Hurricane Lee and Tropical Storm Margot.

A surface trough meander northeastward from the southeast Bahamas
to near Bermuda at 31N64W. Scattered showers and isolated
thunderstorms are found up to 120 nm along either side of this
feature. Convergent easterly winds north of Hurricane Lee are
generating widely scattered moderate convection from 23N to 26N
between 45W and 53W. An upper-level low in the central Atlantic
near 29N44W is producing similar conditions north of 26N between
41W and 45W. Farther southeast, a 1013 mb low and its related
surface trough are causing widely scattered showers from 25N to
27N between 33W and 38W. Moderate to fresh NE to E winds and seas
of 6 to 8 ft are also found in this area.

The following descriptions are outside the areas impacted by Lee,
Margot and the 1013 mb low mentioned above. Gentle to locally
moderate NNE to E winds and seas of 4 to 6 ft in moderate
northerly swell are evident north of 20N between the Africa coast
and 65W, including the Canary Islands. Farther west, light to
gentle with locally moderate E to SE winds and 3 to 5 ft seas
dominate north of 20N between 65W and the Georgia-Florida coast.
For the tropical Atlantic, gentle to moderate with locally fresh
NE to SSE winds and seas at 5 to 8 ft are seen from 10N to 20N
between 20W and the Lesser Antilles. Farther east, light to gentle
monsoonal winds and seas of 4 to 7 ft in moderate northerly swell
are present north of 10N between the central Africa coast and 20W.
Gentle to moderate southerly winds and 6 to 9 ft seas in mixed
northerly and southerly swells prevail for the rest of the
Atlantic Basin.

For the forecast W of 55W, Hurricane Lee is expected to
strengthen further through Fri morning, and move to near 18.1N
54.0W Fri morning and near 19.1N 56.1W Fri evening. It will reach
near 20.1N 58.0W Sat morning, 20.9N 59.6W Sat evening, 21.5N 60.9W
Sun morning and 22.1N 62.2W Sun evening. Large swell from
Hurricane Lee will reach waters near 58W Fri morning, then begin
to impact the Anegada Passage and adjacent waters Sat afternoon,
and the Mona Passage beginning Sun morning. Beyond Sun, Lee is
expected to begin to turn more northwest and weaken very slowly.

$$

Forecaster Chan
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