[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192137
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Oct 20 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
2115 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is along 32W from 14N southward,
moving westward around 15 kt. Little signature of this wave is
noted at the surface. Isolated to scattered moderate convection is
noted from 00N to 08N between 28W and 40W.

The axis of a tropical wave is along 55W from 18N southward,
moving westward around 15 kt. Little signature of this wave is
noted at the surface. No significant convection is noted near this
tropical wave.

The axis of a tropical wave is along 63W from 18N southward,
moving westward around 15 kt. The wave axis was noted from the
earlier 1200 UTC Barbados and Trinidad 700 mb rawindsonde winds.
Isolated showers and thunderstorms are noted in the vicinity of
the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends off the coast of Africa near the
border of The Gambia and Senegal at 12N16W to 10N20W. The ITCZ
continues from 10N20W to 04N40W to 03N44W. Scattered moderate to
isolated strong convection is from 02N-08N between 27W-40W.
Scattered moderate convection is noted from 06N- 10N between
43W-50W.

GULF OF MEXICO...

A 1024 mb high is centered north of the area near Hilton Head
Island, South Carolina. A surface trough extends from the central
Gulf of Mexico near 25N91W to the eastern Bay of Campeche near
18N94W. Moderate to fresh easterly winds are noted over the basin
north of 27N between 88W and 94W, and east of 88W as well due to
the pressure gradient between the trough and high. Seas are 3 to 5
ft across these same waters. Mainly light to gentle winds and seas
of 2 to 4 ft prevail elsewhere.

For the forecast, a ridge will dominate the Gulf of Mexico waters
during the forecast period. Moderate to fresh easterly winds are
expected over the north-central, and NE Gulf through Wed, and
across the SE Gulf through Wed night. Gentle to moderate winds
will prevail elsewhere.

CARIBBEAN SEA...

A weak pressure pattern exists across the Caribbean waters with
gentle to moderate trades prevailing, except light to gentle south
of 11N in the SW Caribbean. Seas are mainly 2 to 4 ft, except 1 to
3 ft south of 11N in the SW Caribbean. Scattered moderate and
isolated strong convection is noted over the Caribbean from 11N to
21N west of 80W, with additional showers and thunderstorms across
mainly of the islands due to afternoon heating.

For the forecast, high pressure building north of the area will
bring fresh to locally strong trades east of the Windward Islands
Wed through Sun. During this period, moderate to fresh winds are
expected over the south-central Caribbean, including the Venezuela
basin, with gentle to moderate trade winds elsewhere. A pair of
tropical waves will move westward across the E and central
Caribbean over the next 72 hours.

ATLANTIC OCEAN...

A cold front extends from 31N56W to 25N70W where it becomes
stationary to the central Bahamas. NE winds are moderate to fresh
north of the frontal boundary. Scattered showers are occurring
within 60 NM of the front. Seas are mainly 3 to 6 ft west of the
front. Northeast of the Lesser Antilles, a trough extends from
25N37W to 1012 mb low pressure near 28N40W to 24N54W, with another
trough from 22N55W to 16N60W. Winds are moderate or weaker in the
vicinity of the troughs. Scattered showers are occurring within
60 NM of the troughs. Farther east, a stationary front enters the
discussion waters from 31N26W to 27N28W, then becomes a trough
extending to 24N32W. Winds west of the front and trough to 35W
are moderate to fresh, along with 5 to 8 ft seas. Scattered
showers are occurring within 60 NM of the front/trough. North of
the ITCZ to 21N, the NE to E trades are moderate to fresh, with
gentle to moderate winds elsewhere. Seas are mainly 4 to 7 ft in
mixed swell across the remainder of the waters.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021. Ash
emission on-going. 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 55W, the front will remain nearly
stationary from 25N65W to the central Bahamas on Wed before
dissipating on Thu. High pressure in the wake of the front will
shift eastward across the W Atlantic along 31N-32N through Thu,
producing moderate to fresh winds immediately north of the front.

$$
Lewitsky
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