[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190542
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Oct 19 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 29N from
02N to 16N, moving westward at 10-15 kt. Scattered moderate to
isolated strong convection is within 120 nm east of the wave axis
from 05N to 07N.

A central Atlantic tropical wave has its axis along 48W from 02N
to to 17N, moving westward at 10-15 kt. Latest and recent
satellite imagery depicts the cloud pattern of this wave quite
noticeably. The imagery shows scattered moderate convection within
120 nm east of the axis from 08N to 10N. A recent ASCAT pass
revealed a northeast to east-southeast shift of gentle winds
across the wave axis.

Another central Atlantic tropical has its axis from 20N58W to
14N59W and south to inland Guyana. It is moving westward at
10-15 kt. This wave is underneath an elongated northeast to
southwest upper-level trough that is aiding the scattered
moderate convection occurring within 120 nm east of the wave axis
from 12N to 20N. A recent ASCAT pass revealed a gradual northeast
to east-southeast shift of gentle winds across the wave axis.

A western Caribbean Sea tropical wave has its axis near 83W
south of 16N. It is moving westward at about 10 kt. Scattered
moderate to isolated strong is near the northern part of the
wave from 14N to 16N between 81W-84W. Similar convection is just
to the northwest of the wave from 16N to 18N between 83W-85W.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends off the coast of Senegal near
16N17W and continues to 07N24W. The ITCZ continues from 07N24W
to 06N28W. It then resumes near 06N30W to 06N39W to 07N46W and
continues to the west of a tropical wave from 07N49W to 05N53W.
In addition to the convection mentioned above in the Tropical
Waves section above, scattered moderate to isolated strong
convection is within 60 nm north of the ITCZ between 29W-40W,
and within 30 nm south of the ITCZ between 40W-45W. Scattered
moderate convection is within 30 nm north of the ITCZ between
24W-27W.

GULF OF MEXICO...

A stationary front extends from the Straits of Florida to 22N90W
and to 18.5N93W. Recent ASCAT data shows gentle to moderate east
winds north of the front, except for fresh northeast to east winds
over the Straits of Florida and gentle to moderate north winds
over the southwest Gulf. Seas are 4-6 ft in the southwest Gulf
and in the Straits of Florida, and 3 to 5 ft elsewhere except
for slightly lower seas of 2-4 ft in the west-central Gulf area.

For the forecast, the front will slowly dissipate through Wed.
Winds across the Gulf will gradually veer to the E Tue as high
pressure to the N slides eastward. Weak high pres will dominate
the Gulf for the remainder of the week

CARIBBEAN SEA...

Refer to the section above for details on the tropical waves
moving across the basin.

A weak pressure pattern prevails across the Caribbean waters.
Moderate to fresh east winds are noted off Venezuela, and along
the ABC islands per recent ASCAT data passes. Seas of 2-4 ft are
over these waters.  Light to gentle winds and seas of 1-3 ft
continue elsewhere across much of the Caribbean waters, except
for higher seas of 3-5 ft over the northwestern Caribbean.

For the forecast, the weak pressure gradient and tranquil marine
conditions will persist across the Caribbean basin through
this morning. A cold front across the NW Atlantic will move
southeastward through Wed before stalling from near 25N65W to the
Straits of Florida. High pressure building north of the front
will bring a return to moderate trade winds to the Caribbean early
Tue and then become moderate to fresh winds Wed through Sat.

ATLANTIC OCEAN...

Refer to the section above for details on the tropical waves
moving across the basin.

A cold front extends across the Atlantic waters from near 31N61W
to the central Bahamas where it becomes a stationary front to
across the Straits of Florida. Recent ASCAT data passes indicate
moderate to fresh north to northeast winds within 90 to 120 nm
north of the front and mainly gentle northeast to east winds
elsewhere north of the front. Seas are in the range of 6-8 ft due
to a northwest swell. Moderate to fresh southwest winds along with
seas of 4-5 ft are east of the front to 50W and north of 28N.
Gentle winds persist elsewhere west of 50W along with 3-5 ft seas
due to a north to northeast swell. Farther east, another cold
front reaches from near 31N27W to 27N32W, where it becomes a
weakening stationary front to 26N43W and a trough from there to
22N50W and to near 20N50W. Northwest swell producing seas peaking
at 8 ft is following in behind this front north of 31N. This swell
set if forecast to move through the waters north of 30N and
between 35W-41W later this morning. Weak high pressure dominates
elsewhere supporting gentle to moderate trades south of 20N along
with 4-6 ft seas, with the exception of moderate to fresh trades
between 28W-47W, and gentle winds north of 20N with 5-7 ft seas
due to a northwest swell.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. An ash
emission is ongoing. Light to moderate volcanic ash is expected
in the area east of the volcano, while high ash concentrations are
in the vicinity of the volcano. Lower volcanic ash cloud is
drifting to the southwest. Marine and aviation interests should
monitor this ongoing situation by reading the Volcanic Ash
Advisory issued by Meteo-France at http://vaac.meteo.fr/volcanoes
/la- palma/.

For the forecast west of 65W, the cold front over the western
Atlantic will continue moving slowly southeastward before
becoming stationary from near 25N65W to the Straits of Florida
late Wed before dissipating Thu night. High pressure will shift
east-southeastward across the western Atlc along 31N-32N through
Thu, producing strong winds immediately north of the front.

$$
Aguirre
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