[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141716
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Thu Sep 14 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...

Hurricane Lee is centered near 30.4N 68.3W at 14/1500 UTC or 210
nm WSW of Bermuda, moving N at 12 kt. Estimated minimum central
pressure is 956 mb. Maximum sustained wind speed is 80 kt with
gusts to 100 kt. Lee is a very large hurricane. Hurricane force
winds extend outward up to 80 NM from the center, and tropical
storm force winds extend outward up to 270 NM from the center.
Seas of 12 ft or greater extend outward from the center 435 NM
NE quadrant, 450 NM SE quadrant, 390 NM SW quadrant and 450 NM
NW quadrant with peak seas to 47 ft. A Saildrone - an uncrewed
vessel - just reported 26 ft significant wave height at 29.4N
66.7W. Numerous moderate and isolated strong convection is noted
within 120 NM of the center. A turn toward the north-northeast
and then northeast is forecast Saturday night and Sunday. On the
forecast track, the center of Lee will pass west of Bermuda
today and tonight, approach the coast of New England and
Atlantic Canada Friday and Saturday, and move across Atlantic
Canada Saturday night and Sunday. Weakening is forecast, but Lee
is expected to remain a large and dangerous hurricane for the
next couple of days.

Hurricane Margot is centered near 36.5N 39.8W at 14/1500 UTC or
620 nm W of the Azores, moving NNE at 5 kt. Estimated minimum
central pressure is 978 mb. Maximum sustained wind speed is 70
kt with gusts to 85 kt. Large swell of up to 10 ft continues
north of 25N between 36W-55W. The winds at least 25 kt
associated with Margot will remain N of 31N for the remainder of
the cyclone's lifetime.

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 Lee
and Margot NHC Forecast/Advisory and Public Advisories at
www.hurricanes.gov for more details.

Invest AL97 in the Central Tropical Atlantic: Showers and
thunderstorms associated with a broad low pressure area located
around 13N39W have increased and become a little better
organized since yesterday. Environmental conditions are expected
to be conducive for additional development, and this system is
likely to become a tropical depression during the day or so
while it moves west-northwestward to northwestward at 10 to 15
kt across the central tropical Atlantic. The chance of this
feature developing into a tropical cyclone during the next 48
hours is high. Peak winds forecast are 25 kt and peak seas of 12
ft through 48 hr in connection with this system. Please refer to
the latest NHC Tropical Weather Outlook at www.hurricanes.gov
for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave previously along 33W has merged
with the tropical wave associated with Invest AL97 along 39W,
from 19N southward, moving westward at 10-15 knots. Scattered
moderate to strong convection is noted from 10N-15N between 28W-
35W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Guinea
Bissau near 13N17W 14.5N17W to AL97 low pressure near 13N39W to
10N50W. Outside of convection described above, scattered to
numerous moderate to strong convection is from 18N-25W between
43W-47W and from 05N-12N east of 26W.

...GULF OF MEXICO...

A stationary front is draped across the N Gulf coast from the
Upper Texas coast at 29N95W to the Florida Panhandle at 30N84W.
Scattered moderate convection is noted north of 28N west of 89W.
A weak 1015 mb high is centered over the central Gulf of Mexico
near 27N89W and light to gentle winds prevail over the Gulf.
Seas are 1-3 ft.

In the forecast, a weak ridge across the northern Gulf will
dominate the basin throughout the forecast period, supporting
mainly light to gentle winds N of 24N and gentle to moderate
winds S of 24N. Scattered thunderstorms can be expected across
the western Yucatan and eastern Bay of Campeche each late
afternoon and evening through the period.

...CARIBBEAN SEA...

With Hurricane Lee to the north of the Caribbean, a weak surface
ridge is present along the spine of the Greater Antilles. The
resulting trades are gentle to moderate over the entire
Caribbean. 4-7 ft swell are propagating through the Mona Pass
this morning into the central and eastern Caribbean, with seas 2-
4 ft elsewhere.

In the forecast, Hurricane Lee will slowly weaken as it passes
west of Bermuda near 32.2N 68.0W this evening with maximum
sustained winds 75 kt gusts 90 kt. Large N-NW swell across the
adjacent Atlantic will move through the NE Caribbean Passage
will gradually diminish this afternoon and tonight and then
decrease quickly Fri. Moderate E trade winds will return to the
Caribbean on Fri.

...ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for details
about Hurricane Lee, Hurricane Margot, and the INVEST AL97.

A weak 1024 mb high is centered just north of our waters near
34N27W with a ridge extending west-southwestward to 27N45W.
Trades are moderate to fresh from the ridge equatorward to the
monsoon trough with seas of 5-9 ft. South of the monsoon trough
and ITCZ winds are gentle to moderate with seas 5-7 ft. Farther
west over the southwestern North Atlantic, the winds are
dominated by the circulation of Lee with cyclonic winds
extending all the way from north of 20N between 60W-80W. Notably
the N to NW winds over Florida, the Florida Straits, and the
Bahamas are not due to a cold front passage, but instead the
circulation of Lee.

For the forecast W of 55W, Hurricane Lee will slowly weaken as
it passes west of Bermuda near 32.2N 68.0W this evening with
maximum sustained winds 75 kt gusts 90 kt, then moves farther
north to near 35.0N 67.2W Fri morning and eventually weaken as
an extratropical cyclone well north of the area over the NW
Atlantic by Sat evening. Long-period swell generated by Lee is
expected to impact all waters north through east of the Bahamas
through the weekend. High pressure will build across the area
late Fri through Sun. Low pressure across the eastern Atlantic,
AL97, will approach the far eastern part of the area Mon and Mon
night, possibly as a tropical cyclone.


$$

CWL/JA
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