[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270554
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Fri Oct 27 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
0535 UTC.

...SPECIAL FEATURES...

Storm Force Wind Warning Northwestern Atlantic (Post-Tropical
Cyclone Tammy): Post-Tropical Cyclone Tammy is centered
near 31.5N 60.0W at 27/0000 UTC. Estimated minimum central
pressure is 980 mb. Gale to storm force winds, reaching near
hurricane force closer to the center of the system N of the area,
and seas of 18 to 26 ft seas are noted from 29N to 31N between
59W and 64W. Scattered moderate and isolated strong convection is
noted from 20N to 31N and between 52W and 60W. This
system is forecast to become separated from the front later today,
and environmental conditions are forecast to become more conducive
over the northwestern Atlantic to the east of Bermuda through
Saturday. Regardless of tropical redevelopment, the system is likely
to bring gusty winds and heavy rainfall to Bermuda during the next
couple of days. Interests on Bermuda should monitor the progress of
this system. This system has a medium chance of tropical cyclone
formation through the next 48 hours. Please read the latest NHC
Tropical Weather Outlook at www.hurricanes.gov and the latest HIGH
SEAS FORECAST at www.hurricanes.gov/marine for more details.

Western Atlantic Rough Seas: Swell generated from Tammy combined
with swell generated from strong gradient flow that developed
west of Tammy is supporting a large area of 12 ft seas over the
western Atlantic waters N of 24N between 55W and 70W. 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. The seas of 12 ft or greater will generally continue over
the waters N of 23N between 55W and 71W before subsiding this
weekend. 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 reaches the Atlantic through the coast of
Senegal near 15N17W and continues to 08N25W. The ITCZ extends from
08N25W to 06N40W. Scattered moderate to isolated strong convection
is observed from 04N to 09N and betwen 20W and 37W.

...GULF OF MEXICO...

At the surface, a 1026 mb high pressure is centered over the
Carolinas and extends southwestward into the Gulf of Mexico. In
the upper levels, a broad high pressure sits over the SE Gulf
helping to suppress the development of deep convection. Shallow
moisture patches are seen traveling westward across the basin
producing light, fast-moving showers. The pressure gradient
between the ridge and lower pressures in the deep tropics
support fresh to locally strong easterly winds south of 26N,
along with seas of 6-9 ft. The strongest winds and highest seas
are occurring north of the Yucatan Channel and off Pinar del
Rio, Cuba. Mainly moderate easterly winds and seas of 3-6 ft are
found in the remaining waters.

For the forecast, high pressure centered north of the area will
continue to support moderate to fresh winds, strong in the
eastern Gulf, through the remainder of the week. Mainly gentle NE
winds are expected this weekend 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 building seas over the western Gulf beginning on
Tue.

...CARIBBEAN SEA...

An upper level trough stretches across Hispaniola to Central
America associated with an upper level low located east of the
SE Bahamas. The favorable dynamics, together with abundant
tropical moisture, support scattered showers and isolated
thunderstorms in the central Caribbean and Gulf of Honduras. The
east Pacific monsoon trough enters the SW Caribbean near the
Nicaragua and Costa Rica border and continues to northern
Colombia. Similar convection is also observed affecting this
region. In the eastern Caribbean, a surface trough extends from
the Leeward Islands to northern Venezuela. Scattered showers are
evident within 200 nm on both sides of this trough. Dry air
dominates the NW Caribbean, allowing for fairly tranquil weather
conditions.

A tight pressure gradient supports fresh to strong easterly winds
north and east of the surface features described in the paragraph
above, mainly north of 14N and west of 67W. This was also captured
by a recent scatterometer satellite pass. Seas in these waters are
5-8 ft, with the highest waves occurring between the Cayman
Islands and western and central Cuba. Moderate or weaker winds and
3-6 seas prevail elsewhere. However, seas to 7 ft are present in
the water passages in the NE Caribbean due to the large swell
region associated with the strong extratropical cyclone located
southeast of Bermuda, the remnants of Tammy.

For the forecast, strong high pressure N of the area will
continue to support fresh to occasionally strong NE to E winds in
the NW and north- central Caribbean, including the Windward
Passage through the week. Gentle winds are expected elsewhere.

...ATLANTIC OCEAN...

Please read the Special Features section above for more on a Storm
Warning associated with Post-Tropical Cyclone Tammy southeast of
Bermuda, and rough seas across the SW tropical Atlantic.

The remainder of the tropical Atlantic is dominated by a
subtropical ridge located near the Azores. A surface trough in the
eastern Caribbean is also generating an area of showers and
isolated thunderstorms to the east of the Lesser Antilles. Farther
east, an upper level trough is producing showers and thunderstorms
from 05N to 16N and between 40W and 50W. The pressure gradient
between the ridge and lower pressures in the deep tropics support
fresh to locally strong easterly winds and seas of 6-8 ft south of
14N and between 30W and 50W. A similar pattern sustains fresh to
locally strong NE winds off western Africa, mainly from 15N to 24N
and east of 30W. Seas in these waters are 6-8 ft. Elsewhere,
moderate or weaker winds and moderate seas prevail.

For the forecast W of 55W, a strong extratropical cyclone, former Tammy,
associated with an occluded front is located near 31.5N60W. This
system is forecast to become separated from the front during the
next day or so, and environmental conditions are forecast to become
more conducive for the low to regain tropical characteristics while
it meanders over the northwestern Atlantic to the east of Bermuda
through Saturday. Currently, high winds and hazardous seas are
still present, and a Storm Warning remains in effect for portions
of the area SE of Bermuda. Gales will continue into Fri. The
gradient between this low and high pressure N of the area will
continue to support strong to near gale-fore NE winds and very
rough seas well W of the low across much of the forecast area
through the week.

$$
DELGADO
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