[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280453
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sat Oct 28 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
0435 UTC.

...SPECIAL FEATURES...

Tropical Storm Tammy is near 32.7N 61.3W at 11 PM EDT, and is
moving north-northwest at 4 kt. Maximum sustained winds are 50 kt
with gusts to 60 kt, and the minimum central pressure is 991 mb.
Peak seas are 24 ft. Sheared Tammy is producing scattered
moderate convection over the northern quadrant. A turn toward
the north and northeast is expected through early Saturday, followed
by a faster eastward to east-southeastward motion on Sunday and
Monday. On the forecast track, Tammy will move away from Bermuda on
Saturday. Weakening is expected during the next few days, and
Tammy is forecast to become a post-tropical remnant low 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 Tammy
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Western Atlantic Rough Seas: A subtropical ridge over the
Carolinas combines with a low level trough than extends from S of
Tammy to the NE Caribbean to produce a large area of fresh to
locally strong winds and very high seas between Tammy and the
Bahamas. A large area of 12-13 ft seas is just northeast of the
Bahamas and the Turks and Caicos Islands. These associated high
seas between Tammy and the Bahamas will subside through Sun,
decreasing below 8 ft late Mon. Mariners should either avoid this
region or use extreme caution in this area, depending on your
vessel type and cargo. Hazardous surf and rip currents are also
anticipated along the coast of central Florida, the Bahamas,
Greater Antilles and the northern Leeward Islands. Please read the
latest HIGH SEAS FORECAST issued by the National Hurricane Center
at the website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and
the Offshore Waters Forecast at
https://www.nhc.noaa.gov/marine/offshores.php for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Senegal near 15N17W and continues southwestward to 09N19W. The
ITCZ extends from 09N19W to 04N33W to 05N47W. Scattered moderate
to isolated strong convection is seen on satellite imagery from
04N to 14N and between 27W and 55W.

The eastern North Pacific monsoon trough extends from Central
America along the southern coast of Nicaragua at 11N84W to a
1008 mb low pressure near 11N78W to the coast of Colombia at
11N75W. Scattered moderate and isolated strong convection is
noted south of 13N and between 75W and 80W.

...GULF OF MEXICO...

An expansive 1023 mb high pressure over the Carolinas extends
southwestward into the Gulf of Mexico. A dry airmass only
supports a few patches of isolated, light showers dotting the
Gulf waters. A recent scatterometer satellite pass captured fresh
to strong easterly winds south of 25N and east of 95W. Seas in
these waters are 6-8 ft, with the highest seas occurring in the
eastern Bay of Campeche. Moderate or weaker winds and 4-6 ft seas
prevail elsewhere.

For the forecast, high pressure centered across the middle
Atlantic coastal states will continue to support fresh to strong
winds in the southeast and south central Gulf through early Sun.
Mainly gentle NE winds are expected by Mon as the pressure
gradient weakens and high pressure settles over the region. The
next cold front is forecast to reach the NW Gulf on Mon. This
front will bring gale force winds and quickly building seas over
the western Gulf beginning Mon evening. The front will move SE
through the entire basin by Wed afternoon.

...CARIBBEAN SEA...

A surface trough is analyzed from Puerto Rico to northern
Venezuela. Meanwhile, an active upper level trough stretches
from the Windward Passage to Central America. These features
combined with plenty of tropical moisture result in numerous
showers and isolated thunderstorms east of the surface trough,
affecting Puerto Rico and the Virgin Islands with very heavy
rainfall. Flash flooding is already occurring in Puerto Rico.
The weather pattern will remain very conducive for the development
of showers and thunderstorms across the region during the weekend
and into early next week.

The remainder of the Caribbean is under the influence of the
1023 mb high pressure system over the Carolinas. No deep
convection is noted in the NW Caribbean Sea and most of the
central portion of the basin. The pressure gradient between the
aforementioned ridge and lower pressures in the deep tropics
support fresh to locally strong NE winds north of 16N and west of
75W. The strongest winds are found in the lee of Cuba. Seas in
these waters are 5-8 ft. Fresh to strong southerly winds and seas
of 6-9 ft are evident in the eastern Caribbean due to the strong
storms in the area and the large region of northerly swell
associated with Tammy. Moderate or weaker winds and wave heights
in the 3-5 ft range are present in the rest of the Caribbean.

For the forecast, strong high pressure centered over the middle
Atlantic U.S. coast is combining with elongated low pressure
extending from the W central Atlantic across the NE Caribbean
will support fresh to strong NE to E winds in the NW and
north-central Caribbean, including the Windward Passage through
the weekend. Gentle winds prevail elsewhere. Large N-NE swell
across the W Atlantic will continue to move through the NE
Caribbean Passages through Sun. Broad low pressure is expected
to develop over the W central Caribbean by Sun and move slowly
northward and into the Bahamas through Tue.

...ATLANTIC OCEAN...

Please read the Special Features section above for more
information on Tropical Storm Tammy east of Bermuda, and rough
seas across the SW North Atlantic.

The central and eastern tropical Atlantic are under the influence
of a 1022 mb subtropical ridge positioned near 30N35W. The
pressure gradient between the aforementioned ridge and lower
pressures in the deep tropics result in fresh to locally strong
easterly winds south of 22N, along with seas of 6-9 ft. Farther
east, a broad storm system west of Ireland is producing a large
region of swell that is entering the northeast waters of the
tropical Atlantic, resulting in seas of 8-11 ft north of the
Canary Islands and east of 25W. Elsewhere, moderate or weaker
winds and moderate seas are prevalent.

For the forecast W of 55W, Tropical Storm Tammy is near 32.7N
61.3W at 11 PM EDT, and is moving north-northwest at 4 kt.
Maximum sustained winds are 50 kt with gusts to 60 kt, and the
minimum central pressure is 991 mb. Tammy will move to 32.9N
60.3W Sat morning, 32.6N 57.9W Sat evening, 31.9N 55.0W Sun
morning, 30.5N 52.7W Sun evening, weaken to a tropical
depression near 29.1N 51.6W Mon morning, and become a remnant
low and move to 28.2N 51.6W Mon evening. Tammy will change
little in intensity as it moves to 28.1N 52.2W by late Tue. High
pressure across the middle Atlantic coastal states is combining
with a low level trough than extends from S of Tammy to the NE
Caribbean to produce a large area of fresh to locally strong
winds, with very high seas between Tammy and the Bahamas. These
high seas will slowly subside Sat through Sun. Elongated low
pressure will develop across the SE Bahamas Sun and gradually
drift NW through Tue.

$$
Delgado
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