[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271020
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Gale Warning Northwestern Atlantic (Post-Tropical Cyclone Tammy):
A strong sub-tropical low is centered N of the area near
31.7N60.8W at 27/0600 UTC. An occluded front extends from the low
to 35N53W then a stationary front extends from that point to
23N60W. Estimated minimum central pressure is 985 mb. Gale force
winds prevail N of 30N between 59W and 61W, while strong to near
gale winds prevail N of 28N between 57W and 69W. Seas to 24 ft are
noted within the area of Gale force winds. These wind conditions
will diminish this morning, but long period swell will continue
moving across the Atlantic waters through the weekend. Scattered
moderate and isolated strong convection is noted within 60 nm of
the low and fronts. This system is forecast to become separated
from the fronts 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 the low
described above combined with swell generated from strong
gradient flow that developed west of the low is supporting a
large area of 12 ft seas over the western Atlantic waters N of 23N
between 59W and 74W. 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 area 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 10N23W. The ITCZ extends
from 10N23W to 07N39W. Scattered moderate to isolated strong
convection is observed from 05N to 10N and betwen 25W and 43W.

...GULF OF MEXICO...

Surface ridging prevails across the basin, anchored by a 1025 mb
high centered over the Carolinas. 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 strong easterly
winds south of 25N, 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. Moderate easterly winds and seas of
3-6 ft prevail elsewhere.

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 and east Caribbean. 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 along 65W with scattered
showers. 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 15N and west of 68W. 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.

For the forecast, strong high pressure N of the area will continue to
support fresh to 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
information on the Gale Warning associated with the strong sub-
tropical low 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 north 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 strong easterly winds and seas of
6-8 ft south of 14N and between 36W and 50W. A similar pattern
sustains fresh to locally strong NE winds off western Africa,
mainly from 16N to 23N and east of 28W. Seas in these waters are
6-8 ft. Elsewhere, moderate or weaker winds and moderate seas
prevail.

For the forecast W of 55W, the strong extratropical cyclone is
forecast to become separated from the front today, and
environmental conditions are forecast to become more conducive
over the northwestern Atlantic to the east of Bermuda through
Saturday. Currently, high winds and hazardous seas are still
present, and a Gale Warning remains in effect for portions of the
area SE of Bermuda through this morning. 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.

$$
ERA
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