[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 032159
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
2100 UTC.

...SPECIAL FEATURES...

Hurricane Sam is centered near 38.6N 52.8W at 03/2100 UTC or 490
nm S of Cape Race Newfoundland moving ENE at 14 kt. Estimated
minimum central pressure is 964 mb. Maximum sustained wind speed
is 85 kt with gusts to 105 kt. Sam remains a well-organized
Category 2 hurricane as it moves further into the mid-latitudes.
Numerous moderate and isolated strong convection extends outward
from the center 120 nm. Maximum significant wave height is
estimated at 41 ft, with seas 12 ft and greater extending outward
as far as 400 nm from the center.

A general track to the NE at a
faster forward speed is expected into Tue, before Sam slows and
begins to merge with a trough. Gradual weakening is forecast
during the period, but the wind field associated with Sam will
continue to expand, and it is likely to remain a hurricane until
it transitions into a powerful post-tropical cyclone Tue. Please
read the latest High Seas Forecast issued by the Ocean Prediction
Center at website
https://ocean.weather.gov/mobile/mobile_product.php?id=NFDHSFAT1
and the latest NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

Tropical Depression Victor is centered near 17.1N 41.3W at
03/2100 UTC or 990 nm W of the Cabo Verde Islands moving NW at
11 kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Strong wind
shear continues to displace the convection to the E semicircle.
Scattered moderate to isolated strong convection extends outward
from the center 300 nm in the E semicircle. Maximum significant
wave height near the center is estimated to be near 14 ft and the
seas are expected to gradually decrease over the next few days. A
W to NW motion is expected over the next couple of days. Weakening
is expected and Victor will become a remnant low Mon, then
dissipate 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...

An Atlantic tropical wave has its axis along 22W, south from the
Cabo Verde Islands, moving W at 10 to 15 kt. No deep convection
is noted in association with this wave.

A Caribbean tropical wave has its axis along 70W, south of 20N,
extending from Dominican Republic to NW Venezuela, and is moving
W at 10 to 15 kt. Scattered moderate to strong convection is
noted with and ahead of the wave N of 14N and between 67W and
77W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 15N17W
to 05N30W. The ITCZ is from 05N30W to 10N37W. The ITCZ then
resumes from 09N44W to the coast of Guyana near 07N58W. Scattered
moderate to isolated strong convection is observed within 120 nm
of either side of the monsoon trough and ITCZ between 19W and 37W.


GULF OF MEXICO...

A dome of high pressure positioned between the Outer Banks and
Bermuda extends SW to the Gulf of Mexico, allowing for a weak
pressure gradient across the basin. Moderate E winds are noted in
the SE Gulf and offshore the Yucatan Peninsula, while weaker
winds prevail elsewhere. A surface trough just offshore the Texas
and Mexico coasts remains stationary, but associated convection
has diminished today. Another trough previously over the Bay of
Campeche has dissipated. Seas are 2 to 4 ft in the Gulf, with the
highest seas occurring in the E Gulf waters.

For the forecast, a weak ridge of high pressure north of the Gulf
along 32N will move eastward through Tue, supporting tranquil
conditions across all but the southeast sections of the basin. A
weak cold front will move across the Gulf on Mon and Tue, with
little enhancement of the winds and seas.

CARIBBEAN SEA...

See Tropical Waves section above for details on convection
associated with a tropical wave over the central Caribbean. A
mid- level trough extending from the central Bahamas to eastern
Cuba to near Jamaica is leading to scattered showers and
thunderstorms over Haiti, Jamaica, eastern Cuba, and adjacent
waters. Convection previously associated with the eastern
extension of the eastern Pacific monsoon trough has diminished
this afternoon.

Fresh to locally strong trades encompass the eastern and central
Caribbean Sea, with generally moderate trades elsewhere in the
basin. Seas of 5-7 ft are present in the central and E Caribbean
Sea, while 3-5 ft seas are noted in the W and SW Caribbean.

For the forecast, high pressure will build north of the area.
This will increase winds and seas across the central Caribbean Mon
and Tue. Moderate N to NE swell will affect the tropical Atlc
waters through Tue.


ATLANTIC OCEAN...

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

A deep layer trough extends from 26N67W through the central
Bahamas and southward into eastern Cuba. This trough combining
with rich tropical moisture is resulting in a large area of
showers and thunderstorms across eastern Cuba, Haiti, the eastern
Bahamas, and adjacent waters. Fresh easterlies are occurring to
the east of this trough, W of 67W. A surface trough, extending S
from Hurricane Sam, stretches from 31N55W to 26N61W. Numerous
moderate convection is noted E of this trough axis to around 52W.
Some fresh SSW winds are occurring in the vicinity of this trough
and associated convection.


A broad 1026 mb ridge located near the Azores dominates most of
the NE Atlantic. The pressure gradient between the ridge and
lower pressures in South America results in generally fresh trades
S of 22N between 45W and the Lesser Antilles. The highest winds
are occurring in the waters near the Windward Islands. A similar
pressure gradient occurs in the NE Atlantic between the ridge and
lower pressures found in NW Africa, producing fresh to locally
strong NE winds E of 28W and N of 20N, with the strongest winds
occurring in the waters surrounding the Canary Islands and near
the coast of NW Africa. Mainly moderate winds are present in the
rest of the basin. Outside of the influence of Hurricane Sam and
Tropical Depression Victor, seas of 5-8 ft prevail in the
tropical Atlantic.

For the forecast, swells generated from Hurricane Sam, centered
well NE of the area, will impact the area waters through Mon. High
pressure along the mid Atlc coast will drift slowly eastward
through mid week. This will produce moderate to fresh trade winds
south of 23N and east of the Bahamas through Tue before spreading
into the southeast Bahamas. Active weather is expected to develop
across the waters E of 75W and NE the Bahamas Mon night through
Tue as a surface trough becomes better defined and drifts NW.

$$

KONARIK
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