[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091722
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

Hurricane Lee is centered near 20.3N 58.2W at 09/1500 UTC or 300
nm ENE of the Northern Leeward Islands, moving WNW at 10 kt.
Estimated minimum central pressure is 957 mb. Maximum sustained
wind speed is 100 kt with gusts to 120 kt. Peak seas range
around 41 ft, with the 12 ft sea radii extending from the center
240 nm NE...150 nm SE...210 nm SW...and 330 nm NW quadrants.

Satellite imagery shows that deep convection continues to pulse
near the center of Lee. Numerous moderate to strong convection
is seen from the center up to 114 nm in the SE semicircle, and
80 nm in the E semicircle. Scattered moderate convection is
evident elsewhere from 17N to 23.8N between 53W and 61W. Lee is
a category 3 hurricane on the Saffir-Simpson Hurricane Wind
Scale. Little change in strength is expected today, but gradual
restrengthening is forecast to occur on Sunday and Monday.  Lee
is expected to continue on a W-NW motion and through early next
week with a significant decrease in forward speed beginning
later today and Sunday. On the forecast track, Lee is expected
to pass well to the north of the northern Leeward Islands, the
Virgin Islands, and Puerto Rico into early next week. Dangerous
surf and life-threatening rip currents are affecting portions of
the northern Leeward Islands.  These conditions are spreading
westward and northward and will begin affecting Puerto Rico,
Hispaniola, the Turks and Caicos, the Bahamas, and Bermuda later
today and Sunday.

Tropical Storm Margot is centered near 20.5N 38.0W at 09/1500
UTC or 840 nm WNW of the Cabo Verde Islands, moving WNW at 10
kt. Estimated minimum central pressure is 1004 mb. Maximum
sustained wind speed is 40 kt with gusts to 50 kt. Peak seas of
12 to 15 ft extend outward from the center up to 120 nm in the
NE semicircle, and 15 nm in the S semicircle. Latest satellite
imagery shows numerous moderate to strong convection occurring
in a band extending NE from the center, from 20N to 24N between
32W and 38W. Margot is moving toward the west-northwest and a
west-northwestward to northwestward motion is expected during
the next day or so. A north-northwestward to northward motion is
forecast to begin by late Sunday. Gradual strengthening is
forecast over the next several days, and Margot is forecast to
become a hurricane early next week.

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 eastern Atlantic tropical wave is analyzed near 24W 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 24W and 28W. 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 17N16.5W then
reaches southwestward to south of the Cabo Verde Islands at
14.5N24W, before resuming from 12N34W to 07N43W. The ITCZ begins
at 07N43W and ends at 07N49W. Scattered moderate convection is
present south of the trough from 05N to 12N between the Sierra
Leone coast and 21W.

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 southward to near 27N and across the Louisiana/Texas
border coastal waters. Isolated thunderstorms are occurring near
the front. However, isolated small clusters of showers and
moderate thunderstorms are occurring across the Florida Big
Bend, and offshore of south-central Texas. In addition, an
outflow boundary has developed in the offshore waters of south-
central Texas. A surface trough near the west coast of the
Yucatan Peninsula is causing isolated showers and thunderstorms
across the Bay of Campeche. Otherwise outside of convection,
modest ridging related to a 1016 mb high along the E Texas coast
is producing light to gentle winds with 1 to 2 ft seas across
the basin.

For the forecast, a weak ridge will dominate the Gulf waters
throughout the forecast period supporting light to moderate
winds.

...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 9 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, Hurricane Lee is near 20.3N 58.2W at 11 AM
EDT, and is moving west-northwest at 10 kt. Maximum sustained
winds are 100 kt with gusts to 120 kt, and the minimum central
pressure is 957 mb. Lee will move to 21.0N 59.3W this evening,
21.7N 60.6W Sun morning, 22.4N 61.9W Sun evening, 22.9N 63.1W
Mon morning, 23.3N 64.2W Mon evening, and 23.6N 65.3W Tue
morning. Lee will change little in intensity as it moves to near
24.4N 67.0W early Wednesday. In the Caribbean, moderate to fresh
trade winds will continue in the central and E Caribbean through
the weekend. Large easterly swell over the tropical Atlantic
waters has reached the passages of the NE Caribbean this
morning, and will reach the Anegada Passage by midday today, and
the Mona Passage Sun.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section above for details
on Major Hurricane Lee and on Tropical Storm Margot. For
convection information across the tropical Atlantic, please see
the TROPICAL WAVES and MONSOON TROUGH/ITCZ sections.

A modest but persistent surface trough extends northeastward from
the central Bahamas to west of Bermuda near 31N72W. Scattered
showers and isolated thunderstorms are present near and up to 180
nm east side of this feature, including the rest of the
Bahamas. An upper-level low at the central Atlantic near 29N45W
is producing scattered moderate convection north of 28N between
43W and 48W

North of 20N, fresh to locally strong NE to ESE peripheral winds
of Hurricane Lee and Tropical Storm Margot are found northward
to 27N between 51W and 64W, and between 32W and 42W
respectively. Otherwise, gentle to moderate NE to SE winds and
seas of 5 to 8 ft in mixed swell dominates north of 24N between
25W and the Georgia-Florida coast. From 05N to 24N 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 5 to 8 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 23W. 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 near 20.3N 58.2W at
11 AM EDT, and is moving west-northwest at 10 kt. Maximum
sustained winds are 100 kt with gusts to 120 kt, and the minimum
central pressure is 957 mb. Lee will move to 21.0N 59.3W this
evening, 21.7N 60.6W Sun morning, 22.4N 61.9W Sun evening, 22.9N
63.1W Mon morning, 23.3N 64.2W Mon evening, and 23.6N 65.3W Tue
morning. Lee will change little in intensity as it moves to near
24.4N 67.0W early Wednesday. Large easterly swell over the
passages of the NE Caribbean will reach the Anegada Passage by
midday today, the Mona Passage on Sun, the Turks and Caicos
Islands Sun evening and the southeastern Bahamas Mon.

$$
KRV
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