[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 022158
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Oct 3 2021

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 1800 UTC surface analysis and satellite imagery through
2130 UTC.

...SPECIAL FEATURES...

Major Hurricane Sam is centered near 35.4N 58.2W at 02/2100 UTC or
380 nm ENE of Bermuda moving NE at 15 kt. Estimated minimum
central pressure is 950 mb. Maximum sustained wind speed is 110 kt
with gusts to 135 kt. Sam remains a well-organized hurricane as
it moves farther away from Bermuda. Numerous moderate to strong
convection extends outward from the center 180 nm in the N
semicircle and 90 nm in the S semicircle. Scattered moderate
convection exists elsewhere within 300 nm in the NE quadrant.
Maximum significant wave height near the center is estimated at
45 ft, with seas 12 and greater extending outward as far as 330 nm
from the center. A general track to the NE with an increase in
forward speed is expected for the next few days, with a gradual
turn more toward the N early next week. Slow weakening is
forecast, but Sam could remain a major hurricane for the next day
or so. After 36 hours, more significant weakening is anticipated.
Sam is likely to transition to a powerful extratropical cyclone
Tue. Please read the latest High Seas Forecast issued by the
Ocean Prediction Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT1.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

Newly-downgraded Tropical Depression Victor is centered near
13.7N 38.0W at 02/2100 UTC or 830 nm W of the Cabo Verde Islands
moving NW at 12 kt. Estimated minimum central pressure is 1007 mb.
Maximum sustained wind speed is 30 kt with gusts to 40 kt.
Numerous moderate to isolated strong convection is occurring in
the NE quadrant between 60 and 300 nm from the center. There is
no significant convection elsewhere near the center. Maximum
significant wave height near the center is estimated to be near 15
ft, and the seas should gradually diminish during the next couple
days. A general NW motion is expected to continue over the next
few days. Strong wind shear and dry air will continue to lead to
weakening of Victor, and the system is likely to degenerate into a
remnant low tonight, and open into a low pressure trough by early
Tue. 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 at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

A tropical wave has moved into the far eastern Caribbean, with its
axis along 63W to the S of 19N, from the Virgin Islands to
northern Venezuela. It is moving W at around 10 kt. The wave is
embedded in a dry airmass that is suppressing the shower and
thunderstorm activity, although some convection as developed this
afternoon along the Venezuelan coast.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 14N17W
to 06N21W. The ITCZ then extends from 06N21W to 07N30W. The ITCZ
resumes near 07N41W to 06N54W. Aside from convection associated
with T.S. Victor, scattered moderate to isolated strong convection
is observed within 150 nm of the monsoon trough and the ITCZ to
the E of 25W. Scattered moderate convection is also noted within
120 nm north of the ITCZ between 42W and 57W.

GULF OF MEXICO...

The Gulf of Mexico is the SW periphery of a 1024 mb high pressure
position over the SE United States. A surface trough is located
in the NW Gulf within 60 nm of the coast of Texas and NE Mexico,
especially from 30N94W to 24N97W. Scattered moderate convection
is present within 150 nm to the east of the trough axis. A surface
trough previously in the Bay of Campeche has dissipated this
evening. Fresh E-SE winds are occurring in the SE Gulf,
including the Florida Straits, while gentle to moderate winds
prevail elsewhere. Seas of 3 to 5 ft are prevalent in the SE
Gulf, with the highest seas occurring in the Florida Straits. Seas
of 2-4 ft are present elsewhere in the Gulf.

For the forecast, the weak ridge of high pressure will persist
north of the Gulf through tonight, supporting tranquil conditions
across the western half of the basin. Stronger higher pressure
will build across the region on Sun, allowing winds and seas to
increase over the SE Gulf. A weak cold front will move across the
Gulf on Mon and Tue, with little enhancement of the winds and
seas.

CARIBBEAN SEA...

An upper level trough over the W Atlantic reaches into the W
Caribbean Sea, enhancing the development of scattered showers and
isolated thunderstorms north-central basin. The most concentrated
activity is noted N of 13N between 63W and 75W. Scattered
moderate convection is also observed in the SW Caribbean, mainly
within 150 nm north of Panama. Generally fresh trades are
occurring over the central and eastern basin, with some localized
strong winds occurring offshore NW Venezuela. Moderate winds
prevail elsewhere, except for some light to gentle winds in the
far SW Caribbean. Seas of 4-6 ft are found E of 75W and 2-4 ft
elsewhere.

For the forecast, high pressure will build north of the area
through the weekend. This will bring an increase in trade winds
and seas across the central and E Caribbean as well as the
tropical N Atlantic later this weekend through the middle of next
week.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on Major
Hurricane Sam and newly-downgraded Tropical Depression Victor.

The Cumbre Vieja volcano on the island of La Palma in the Canary
Islands near 28.6N 17.8W has been erupting since September 19th.
High concentration of volcanic ash is found near the volcano.
Marine and aviation interests should monitor this ongoing
situation by reading the latest Volcanic Ash Advisory issued by
Meteo-France at http://vaac.meteo.fr/volcanoes/la-palma/ for
details.

An expansive 1025 mb high pressure centered WSW of the Azores is
dominating most of the basin. Aside from the influences of the
aforementioned tropical cyclones, the only other feature of note
is an upper level trough over the SW Atlantic. Divergence
associated with this trough and abundant tropical moisture are
inducing numerous moderate to isolated strong convection S of 25N
between 65W and 72W.

Fresh NE to E winds prevail W of 70W and S of 28N, including
waters offshore the Florida Peninsula, Bahamas, and Turks and
Caicos Islands. To the SE, a broad area of fresh NE to E trades is
located S of 23N across the Atlantic. Outside of the two tropical
cyclones, seas of 6 to 9 ft prevail across the basin.

For the forecast, swells generated from Hurricane Sam, centered
NE of the area, will impact the area west of 62W through the rest
of the weekend. High pressure will build across the area in the
wake of Sam, which will bring moderate to fresh winds Mon through
mid week.

$$
KONARIK
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