[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121617
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Sep 12 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
1600 UTC.

...SPECIAL FEATURES...

Major Hurricane Lee is centered near 24.3N 65.9W at 12/1500 UTC
or 480 nm south of Bermuda, moving WNW at 5 kt. Estimated minimum
central pressure is 951 mb. Maximum sustained wind speed is 100 kt
with gusts to 120 kt. An eyewall continues to consolidate near
the center of Lee. Numerous moderate to isolated strong
convection is evident within 60 nm in the northern semicircle of
Lee, and within 120 nm in the southern semicircle. Seas in excess
of 12 ft reach as far as 360 nm from the center of Lee. While the
core of the hurricane is forecast to pass west of Bermuda, the
large wind field of the storm is likely to bring wind impacts and
heavy rainfall to the island by Thu. Little change in strength is
forecast during the next couple of days. Dangerous surf and life-
threatening rip currents will affect portions of the northern
Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, the
Turks and Caicos Islands, the Bahamas, Bermuda, and most of the
U.S East Coast through much of the week. Please consult products
from your local weather office.

Hurricane Margot is centered near 30.2N 39.4W at 12/1500 UTC or
770 nm SW of the Azores, moving N at 10 kt. Estimated minimum
central pressure is 975 mb. Maximum sustained wind speed is 75
kt with gusts to 90 kt. Scattered moderate to isolated strong
convection is evident within 75 nm in the northern quadrant of the
hurricane. Seas in excess of 12 ft reach as far as 240 nm of the
center of Margot. The hurricane will intensify slightly as it
continues to  move northward into Wed, before turning more NNW.

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...

An Atlantic tropical wave extends from 05N to 17N along 23W,
moving west at 10 kt. 1009 mb low pressure is along the wave axis
where it intersects the monsoon trough at 12N. No significant
convection is noted near this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean through the coast
of Senegal near 14N17W, then continues to 1009 mb low pressure
near 12N23W to broad 1010 mb low pressure near 12N32W (AL97 and
AL98)to 1010 mb low pressure near 15N49W. A few showers and
thunderstorms are noted within 240 to 300 nm in the southwest
quadrant of the 1010 mb low pressure near 12N32W.

...GULF OF MEXICO...

A trough extends across the far northwest Gulf off the coast of
Louisiana to the central Texas coast. Weak high pressure is
developing over the east-central Gulf. This pattern is maintaining
light breezes and slight seas across the basin. No significant
convection is evident in the Gulf at this time.

For the forecast, the weak ridge will dominate the Gulf waters
throughout the forecast period supporting mainly light to gentle
winds. Moderate return flow will develop across the W and SW
Gulf Thu night. Scattered thunderstorms can be expected across
the western Yucatan and eastern Bay of Campeche each late
afternoon and evening.

...CARIBBEAN SEA...

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

The subtropical ridge that is normally north of the region is
disrupted by Hurricane Lee, resulting in gentle to moderate
easterly breezes across the basin. Northerly swell reaching 5 to 8
ft from Lee is penetrating the Anegada and Mona Passages, with
plumes of 4 to 6 ft combined seas extending south of passages
across the northeast Caribbean. Combined seas are 2 to 4 ft
elsewhere. No significant convection is evident elsewhere.

For the forecast, the northerly swell over the northeast Caribbean will
diminish significantly Thu through Fri. Building high pressure
north of the area will mean moderate to locally fresh trade winds
will return to the Caribbean Fri.

...ATLANTIC OCEAN...

Please see the Special Features section for information about
Major Hurricane Lee and Hurricane Margot.

A recent scatterometer satellite pass indicated a broad area of
1010 mb low pressure is centered along the monsoon trough over the
eastern Atlantic near 12N32W. The NHC was analyzing this feature
as two separate invest areas in the eastern Atlantic (AL97 and
AL98), but these have been consolidated into one elongated low. A
few showers and thunderstorms are evident within 240 to 300 nm to
the southwest of the low. Gradual development of the low is
expected and a tropical depression is likely to form by this
weekend while the system moves west-northwestward or northwestward
at about 15 mph across the central tropical Atlantic. There is a
low chance of development through the next couple of days, but
high chance of development through the next seven days.

Elsewhere, no significant convection is evident across the
subtropical or tropical North Atlantic outside of the immediate
area near Lee and Margot. Seas in excess of 8 ft due to Lee cover
the area between 55W and 75W, and due to Margot are evident north
of 23N between 35W and 50W. Gentle to moderate winds are noted
elsewhere with 4 to 6 ft combined seas in mixed swell.

For the forecast west of 55W, Lee will move to 24.8N 66.6W this
evening, 25.9N 67.3W Wed morning, 27.4N 67.8W Wed evening, 29.4N
68.2W Thu morning, 31.6N 68.0W Thu evening, and 34.3N 67.4W Fri
morning. Lee will change little in intensity as it moves well NW
of Bermuda early Sat. Large E to SE swell dominating the waters
east of 78W will continue to propagate westward across the Atlc,
reaching the Florida coasts this afternoon or evening. Large swell
from Lee will dominate the regional waters through Fri.

$$
Christensen
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