[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031048
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
0930 UTC.

...SPECIAL FEATURES...

Hurricane Sam is centered near 37.3N 55.9W at 03/0900 UTC or 575
nm SSW of Cape Race Newfoundland, moving NE at 15 kt. Estimated
minimum central pressure is 960 mb. Maximum sustained wind speed
is 90 kt with gusts to 110 kt. Numerous moderate and isolated
strong convection extends outward from the center 90 nm. Maximum
significant wave height is estimated at 39 ft, with seas 12 ft
and greater extending outward as far as 300 nm from the center. A
general track to the NE with an increase in forward speed is
expected for the next few days. Slow weakening is anticipated
during the next few days, and Sam should transition into a
powerful post-tropical cyclone on Monday night. 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 16.1N  39.9W at
03/0900 UTC or 915 nm W of the Cabo Verde Islands, moving NW at
14 kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Scattered
moderate to strong convection extends outward from the center 360
nm in the NE quadrant. Maximum significant wave height near the
center is estimated to be near 14 ft. A general NW motion is
expected to continue over the next few days. Gradual weakening is
forecast over the next couple of days, and Victor is expected to
become a remnant low tonight. The system is then forecast to
dissipate by Tuesday night. 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 new tropical wave along the coast of west Africa is along 20W
from 03N-19N, moving W at 10-15 kt. Scattered moderate convection
is within 150 nm either side of the wave axis from 12N-18N.

An eastern Caribbean tropical wave has its axis along 66W from
16N southward to Venezuela, moving W at 15 kt. Scattered moderate
to strong convection is noted with and ahead of the wave from
12.5N to 18.5N between 65W and 73W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 13.5N17W
to 07N20W. The ITCZ is from 07N20W to 06.5N33W, where there is a
break in the ITCZ. The ITCZ resumes from 08N42W to 06N50W to
08.5N60W. Scattered moderate isolated strong convection is noted
from 01.5N-12.5N E of 34W to African coast, and within 60 nm along
and N of ITCZ between 56W and 61W.

GULF OF MEXICO...

Mid to upper-level ridging is present over the Gulf of Mexico.
While the mid-level ridging is causing some subsidence over the
southern Gulf, ample moisture is present over the northern Gulf.
Scattered moderate isolated strong convection is noted over the
north- central and northeast Gulf of Mexico, north of 25.5N
between 85W and 94W. A small cluster of strong tstorms is along
the western Bay of Campeche between Tuxpan and Veracruz. Overnight
ASCAT data show fresh E winds in the Florida Straits and SE Gulf
of Mexico, where seas are 4 to 5 ft. Gentle to moderate E to SE
winds are noted elsewhere across the basin, with 2 to 3 ft seas.

A weak ridge of high pressure north of the Gulf extends from the
western Atlantic westward along 34N, and  will move eastward
through Tue. This will support 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...

An upper-level trough extends from the NW Bahamas to central Cuba
to Nicaragua. Showers and tstorms are being enhanced along and to
the east of the upper-level trough axis. Scattered moderate and
isolated strong thunderstorms cover the north-central Caribbean,
north of 15.5N between 69W-81W. Strong convection is seen in the
south-central to SW Caribbean south of 13N between 70W-80W.
Overnight ASCAT data show fresh trades in the eastern and central
Caribbean, mainly south of 17.5N and east of 77W, where seas are
4 to 6 ft. Moderate trades prevail across most other areas, where
seas are 2 to 4 ft. NOAA buoy 42060, located near 16.4N 63.3W has
recently reported 19 kt winds and 6 ft seas. Earlier altimeter
data from Saturday afternoon showed seas of about 5 feet from 14N-
17N between 67W-69W.

High pressure along the mid Atlc coast along 34N  will produce
fresh tradewinds from the central Caribbean to the tropical N
Atlantic today and persist across the Caribbean through Tue.
Winds and seas will become fresh to strong across the central
Caribbean Mon and Tue as the high pressure moves slowly eastward.
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.

West of 60W: A north-south oriented upper-level trough axis
extends over the west Atlantic along 76W. A surface trough
extends from 25N66W to 21N70W. Scattered moderate showers and
tstorms cover the area south of 26N between 63W-80W, with more
numerous moderate convection near the surface trough from 21N-26N
between 63W-69W. Farther north, a 1021 mb high pressure is
centered just offshore of Cape Hatteras, North Carolina.
Overnight ASCAT data show fresh trade winds south of 27N and west
of 72W, including in the Florida Straits. Moderate trade winds are
elsewhere south of 31N and west of 65W. Seas are 5 to 8 ft west
of 65W, in NE swell from Hurricane Sam. Between 60W-65W, 8-12 ft
seas are still occurring north of 27N, but these seas will
gradually subside through Tue as Sam pulls farther away. Buoy
41049 near 27.5N 62.9W is reporting 10 ft seas, mostly in N swell.

East of 60W: An upper-level low is near 32N43W. The positioning
of Hurricane Sam relative to this upper-low is enhancing upper-
level divergence in between the two features, leading to an area
of numerous moderate and isolated strong thunderstorms north of
26N between 46W-56W. Surface ridging covers the remainder of the
eastern subtropical Atlantic, anchored by a 1024 mb high pressure
near 36N33W. Fresh winds cover most of the area from 10N-22N
between 30W-60W, except winds up to 30 kt are near T.D. Victor.
Seas of 7 to 9 ft prevail across this area, except higher near
Victor. Winds near the Windward Islands are fresh to strong. ASCAT
also showed fresh to locally strong NE winds near the Canary
Islands. From 25N-31N between 25W-60W, mainly moderate or weaker
wind speeds prevail, but seas are in the 6 to 8 ft range in mixed
swell from Sam and Victor. The exception is north of 29N and west
of 55W, where larger seas still prevail from swell due to Sam.

Swells generated from Hurricane Sam, centered NE of the area,
will move through the regional waters west of 65W through Mon,
before new northerly swell from Sam spreads south of 30N. 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 develops and drifts NW.

$$
Stripling
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