[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021033
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Oct 2 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Hurricane Sam is centered near 32.8N 60.5W at 0900 UTC, or 220 nm
E of Bermuda, moving NNE at 15 kt. Estimated minimum central
pressure is 945 mb. Maximum sustained wind speed is 115 kt with
gusts to 140 kt. Numerous moderate to scattered 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 50 ft, with seas 12
and greater extending outward as far as 315 nm from the center.
Sam is expected to turn NE by tonight. Weakening is anticipated
over the next couple of days, but Sam should remain a major
hurricane into Sunday. Early next week, Sam should begin to
transition to a strong extratropical storm. 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 Storm Victor is centered near 12.8N 36.3W at 0900 UTC,
or 740 nm WSW of the Cabo Verde Islands, moving WNW at 11 kt.
Estimated minimum central pressure is 1001 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. Scattered moderate to
strong convection is occurring in the NE quadrant between 120-360
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 16 ft, and the seas should gradually
diminish during the next couple days. Middle to upper level wind
shear continues to separate convection from the low level center
of Victor, and is expected to lead to a continued weakening trend
over the next few days. Victor is forecast to move NW and weaken,
likely becoming a tropical depression Sat night and weaken to a
remnant low by 48 hours. 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 axis extends along 58W from 05N to 16N, moving W
at 15 kt. Associated scattered convection is confined along the
ITCZ anddescribed below.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea near 11N16W
to 06N20W. The ITCZ then extends from 06N20W to 09N30W. The ITCZ
resumes to the west of Tropical Storm Victor near 08N39W to
08N57W. Aside from convection associated with Victor, scattered
moderate isolated strong convection extends from 02.5N-12.5N east
of 20W, and from 06N-10N between 42W and 62W.

GULF OF MEXICO...

An eastward-moving short-wave digging across eastern Texas is
inducing upper-level diffluence and rising motion ahead of it over
the western Gulf of Mexico. This, coupled with high moisture
content noted in Total Precipitable Water imagery, is leading to
scattered moderate and isolated strong convection over the western and
NW Gulf of Mexico west of a line from New Orleans to Tampico,
Mexico. Overnight ASCAT data show mainly moderate E winds across
the basin, except for some fresh winds in the Florida Straits,
near the Yucatan Peninsula and in the convection near the Mouth of
the Rio Grande River. Seas are 2 to 4 ft across the basin.

A weak ridge of high pressure will persist north of the Gulf
through early this morning, supporting tranquil conditions across
the west 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...

A fairly modest pressure gradient is supporting mainly moderate
trades over the basin, with seas of 2 to 4 ft. Overnight ASCAT
data show some locally fresh trades in the SE and south-central
Caribbean. An upper-level trough extending from eastern Cuba to
Costa Rica is supporting scattered showers and tstorms covering
much of the eastern and central Caribbean Sea, from Panama
northeastward. West of 74W, additional showers and storms are
found near Jamaica.

For the forecast, high pressure will build north of the area
this weekend, centered along 34N. This will bring an increase in
trade winds and seas across the central and E Caribbean as well as
the tropical N Atlantic this weekend through the middle of next
week.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on Major
Hurricane Sam and Tropical Storm 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.

Aside from Hurricane Sam and Tropical Storm Victor, the tropical
N Atlantic is dominated by ridging from a high pressure of 1026
mb centered near 37N38W. A ridge axis extends SW from that high
pressure to just NE of the Virgin Islands. Moderate anticyclonic
winds prevail near the ridge axis. Southeast of the ridge axis,
fresh NE trades prevail. These winds become strong closer to
Tropical Storm Victor. Hurricane Sam is located NW of that ridge
axis, a couple hundred nm east of Bermuda. Mostly moderate to
fresh NE winds prevail across the western Atlantic, west of 67W
and south of 31N. Outside of the two tropical cyclones, seas of 6
to 9 ft prevail across the basin. A line of broken showers and
thunderstorms about 60 nm wide extends from 27N56W to 20N63W.

Hurricane Sam is northeast of the forecast area near 32.8N 60.5W
and moving NNE near 15 kt. Swell from Hurricane Sam has reached to
the Bahamas, and will reach the east coast of Florida and Georgia
later today. In the area north of 26N and east of 68W, swell from
Sam will be quite significant through today. Swell over the
western Atlantic will begin to subside on Sunday as Sam
accelerates northeastward over the north Atlantic. High pressure
will build into the W Atlantic in the wake of Sam, which will
bring moderate to occasionally fresh winds through Tue.

$$
Stripling
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