[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091111
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Sep 9 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Major Hurricane Lee is near 19.7N 57.4W at 5 AM EDT, or about 385
miles E-NE of the northern Leeward Islands, moving west-
northwest at 10 kt. Maximum sustained winds are 100 kt with gusts
to 120 kt. Minimum central pressure is 963 mb. Peak seas range
around 36 ft, with the 12 ft sea radii extending from the center
270 nm NE...150 nm SE...210 nm SW...and 330 nm NW quadrants. The
latest satellite imagery shows that the eye of Lee is no longer
visible with some banding features still present to the east and
south. Numerous moderate to strong convection is seen from the
center up to 150 nm in the S semicircle, and 75 nm in the N
semicircle. Scattered moderate convection is evident elsewhere
from 15N to 22.5N between 53W and 60W. Lee remains a category 3
hurricane on the Saffir- Simpson Wind Scale. Modest weakening is
expected today before a strengthening trend begins Sun through Mon
night. Lee is expected to continue on a W-NW motion and pass well
north of the northern Leeward Islands this weekend, then pass to
the north of the Virgin Islands and Puerto Rico early next week.
Large swell generated by Lee are affecting the Leeward Islands and
NE Caribbean passages early this morning, and will reach the
Virgin Islands and Puerto Rico Sat afternoon, and Hispaniola on
Sun. Eventually, they will arrive at the Turks and Caicos Islands,
Bahamas and Bermuda Sun evening through Mon. These swells are
likely to cause life- threatening surf and rip current conditions.
Dangerous surf and rip currents are expected to begin along most
of the U.S. East Coast beginning Mon and persist into mid week.

Tropical Storm Margot over the eastern Atlantic is near 19.9N
36.9W at 5 AM EDT, or about 890 miles W-NW of the Cabo Verde
Islands, moving west-northwest at 11 kt. Maximum sustained winds
are 40 kt with gusts to 50 kt. Minimum central pressure is 1004
mb. Peak seas of 12 to 14 ft extend outward from the center up to
90 nm in the NE semicircle, and 15 nm in the SW semicircle.
Latest satellite imagery shows numerous moderate to strong
convection occurring in a band extending NE from the center, from
19N to 23N between 32W and 38W. Margot is forecast to maintain its
present intensity and motion through Sun morning, then turn toward
the northwestward and intensify, reaching hurricane strength near
25.7N 41.4W Mon afternoon. Some gradual strengthening is forecast
thereafter as Margot turns more northward and is expected to move
north of the area Tue night. Peak seas will gradually build near
the center, building to 25 to 30 ft late Tue as it exits the
area.

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.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave is analyzed along 23W from
the Cabo Verde Islands southward, and moving westward around 10
kt. Scattered moderate convection is noted from 11N to the
southern Cabo Verde Islands between 20W and 27W. This wave is
expected to become entrained in the prevailing southeasterly wind
flow that is guiding Margot, which will weaken it and transport it
off to the NW through Sun.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic near Dakar, Senegal then
reaches southwestward to south of the Cabo Verde Islands at
14N26W, before resuming from 12N34W to 07N47W. Scattered moderate
convection is present south of the trough from 05N to 10N between
the Sierra Leone coast and 20W. Widely scattered moderate
convection is noted from 03N to 07.5N between 37W and 42W.

The eastern end of the East Pacific monsoon trough is triggering
scattered showers and thunderstorms across the Caribbean waters
of Costa Rica, Panama and Colombia to the south of 10.5N.

...GULF OF MEXICO...

A very weak stationary front curves westward from the Florida
Panhandle across the Louisiana coastal waters along 27N to near
Galveston, Texas. Isolated thunderstorms occurring near this
feature have dissipated in recent hours. However, isolated small
clusters of showers and moderate thunderstorms are occurring
across the Florida Big Bend, and offshore of SE Texas. A surface
trough near the west coast of the Yucatan Peninsula is causing
scattered showers and isolated thunderstorms across the Bay of
Campeche. Otherwise, modest ridging related to a 1014 mb high
along the SW Louisiana coast is producing light to gentle winds
with 1 to 2 ft seas for the north- central and northeastern Gulf.
Gentle to locally moderate E to SE winds and seas of 2 to 4 ft
prevail for the rest of the Gulf.

Foe the forecast, the weak ridging will dominate the Gulf waters
through midweek next week, supporting only light to moderate
winds. Sporadic thunderstorms will continue this morning near the
stationary front.

...CARIBBEAN SEA...

Please read the SPECIAL FEATURES section about large swell
generated by Major Hurricane Lee impacting the northeast
Caribbean islands.

An upper-level trough extends southward from western Cuba to
northwestern Colombia. Combining with modest convergent easterly
trades, widely scattered showers and thunderstorms are occurring
across the Gulf of Honduras, and south of 10.5N, along the monsoon
trough. A weak trade-wind pattern is persisting across east and
west portions of the basin this morning, with fresh to locally
strong ENE to E winds and seas of 6 to 8 ft occurring in the
south- central basin, including the Gulf of Venezuela. Strong ENE
swell from Lee has begun to enter the passages of the NE Caribbean
recently and will build throughout the day as this swell
propagates westward across the eastern basin.

For the forecast, moderate to fresh trade winds will continue in
the central and eastern basin through the weekend. Large easterly
swell over the tropical Atlantic waters is currently east of 64W
and will reach all of the passages of the northeast Caribbean
this morning, the Anegada Passage by midday Sat, and the Mona
Passage on Sun. This swell will veer more NE early in the week,
and then northerly by Tue and move deep into the eastern Caribbean
basin.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section above for details
on Major Hurricane Lee and on Tropical Storm Margot.

A modest but persistent surface trough extends northeastward from
the central Bahamas to west of Bermuda near 31N70W. Scattered
showers and isolated thunderstorms are present near and up to 180
nm either side of this feature, including the rest of the
Bahamas. An upper-level low at the central Atlantic near 30N43W is
producing scattered moderate convection north of 26N between 43W
and 48W. Another surface trough near 23N42W is generating widely
scattered moderate convection from 17N to 27N between 39W and 43W.
Refer to the Monsoon Trough/ITCZ and Tropical Waves sections for
additional weather in the Atlantic Basin.

North of 22N, fresh to locally strong NE to ESE peripheral winds
of Hurricane Lee and Tropical Storm Margot are found northward to
27N between 50W and 64W, and between 31W and 42W respectively.
Otherwise, gentle to moderate NE to SE winds and seas of 5 to 9 ft
in mixed swell dominates north of 22N between 25W and the
Georgia-Florida coast. From 05N to 22N outside the direct
influence of Lee and Margot, gentle to moderate with locally fresh
NE to SE winds and 6 to 10 ft seas in mixed swells exist between
30W and the Lesser Antilles. Near the Canary Islands, gentle to
moderate with locally fresh NNE to NE trades and seas at 4 to 7 ft
are found north of 18N between the Africa coast and 25W. Near the
Cabo Verde Islands, gentle monsoonal winds and 3 to 5 ft seas are
seen south of 18N between the central Africa coast and 30W.
Gentle to moderate with locally fresh southerly winds and 6 to 10
ft seas in moderate to large southerly swell prevail for the
remainder of the Atlantic Basin.

For the forecast W of 55W, Hurricane Lee is expected to continue
moving W-NW and weaken modestly today before a strengthening
trend begins Sun through Mon night. Lee is expected to move to
near 20.4N 58.7W this afternoon, near 21.8N 61.4W Sun afternoon,
near 22.8N 63.7W Mon afternoon, and to near 23.2N 64.8W Tue
morning. Beyond Tue, Lee is expected to turn more NW and slowly
weaken. Large easterly swell over the tropical Atlantic waters
will enter the passages of the NE Caribbean this morning, the
Anegada Passage by midday today, the Mona Passage on Sun, the
Turks and Caicos Islands Sun evening and the southeastern Bahamas
Mon. Beyond Tue, Lee is expected to turn NW then N and begin to
slowly weaken.

$$
Stripling
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