[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302231
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Oct 01 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
2215 UTC.

...SPECIAL FEATURES...

Hurricane Sam is centered near 23.6N 60.9W at 30/2100 UTC or 560
nm SSE of Bermuda moving NW at 12 kt. Estimated minimum central
pressure is 938 mb. Maximum sustained wind speed is 125 kt with
gusts to 150 kt. Numerous moderate scattered strong convection
is from 22N to 31N between 56W and 67W. Maximum significant wave
height near the center is estimated at 45 ft. On the forecast
track, the core of Sam will pass to the east of Bermuda early
Saturday. Some fluctuations in intensity are expected
during the next couple of days, but Sam is forecast to remain a
major hurricane into Saturday, with more significant weakening
anticipated later in the weekend. Please read the latest NHC
Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml
and Forecast/ Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details.

Tropical Storm Victor is centered near 9.9N 30.0W at 30/2100 UTC
or 510 nm SW of the Cabo Verde Islands moving WNW at 12 kt.
Estimated minimum central pressure is 1003 mb. Maximum sustained
wind speed is 40 kt with gusts to 50 kt. Numerous moderate
convection is from 06N to 14N between 26W and 35W. Maximum
significant wave height near the center is estimated to be near
15 ft. Gradual strengthening is forecast during the next day or so.
However, a weakening trend is expected to begin over the weekend.
Please also read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml for
more details.

...TROPICAL WAVES...

A tropical wave extends from 06N to 15N with axis near 49W,
moving W near 10 kt. Scattered showers are noted in the vicinity
of the wave mainly near 11N49W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the W coast of Africa near
17N16W and continues to 14N22W. The ITCZ begins near 08N33W and
extends to 06N54W. Aside from the convection associated with
Victor and the tropical wave, scattered moderate convection is
from 06N to 10N between 36W and 48W.

GULF OF MEXICO...

Microwave satellite imagery continue to show moisture inflow from
the Caribbean to the western half of the gulf, which along with
middle level divergent flow continue to support heavy showers and
thunderstorms N of 20N and W of 93W. Model guidance suggests that
this activity will continue through the weekend. Otherwise, a
weak surface ridge covers the eastern half of the basin and
provides mainly gentle to moderate E to SE flow basin-wide,
except in the areas of convection where fresh winds are observed.
Seas remains in the 1 to 3 ft range.

For the forecast, a weak ridge of high pressure will persist north of
the Gulf through Fri night, supporting tranquil conditions.
Stronger higher pressure will build across the region by Sun,
allowing winds and seas to increase over the SE Gulf over the
weekend. A weak cold front should move across the Gulf on Mon and
Tue, but with little enhancement of the winds and seas.

CARIBBEAN SEA...

An upper level trough extending a base to the south-central
Caribbean continue to support showers and isolated tstms over E
Cuba and portions of Hispaniola. Diffluent flow to the E of the
upper trough support similar convective activity over the SE
Caribbean waters. With a weak pressure gradient across the region,
latest scatterometer data continue to depict gentle to moderate
trades basin-wide. Seas are 3 ft or less across most of the
Caribbean Sea, except in the northeast Caribbean passages, where
swell from Hurricane Sam will peak through tonight.

For the forecast, Hurricane Sam is well north-northeast of
the Leeward Islands and will continue to generate swells over
Atlantic waters from off the N Leeward Islands to north of the
Mona Passage through Fri. Meanwhile, tranquil trades will prevail
over the Caribbean through Fri. As high pressure builds in
behind Hurricane Sam, winds are expected to become moderate to
fresh across the central and E Caribbean and tropical N Atlantic
by Sat through at least Tue.

ATLANTIC OCEAN...

Refer to the section above for details on Hurricane Sam and T.S.
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.

For the forecast, Hurricane Sam will move to 25.6N 61.5W Fri
morning, 28.5N 61.9W Fri afternoon, 31.3N 61.4W Sat morning, and
then north of our waters by Sat afternoon. Sam will change little
in intensity through Sat. Expect large swell from Sam to impact
the area northeast of the Bahamas starting Fri and continuing
through the weekend. Meanwhile, a weak pressure pattern will
maintain quiescent conditions until tonight. A weak cold front
will move from the Carolinas to the central Bahamas by Fri and
dissipate by Sat. Stronger high pressure will build in to the
area, which will bring moderate to occasionally fresh winds
through Tue.

$$
ERA
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