[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202350 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
Issued by NWS Ocean Prediction Center Washington DC
0005 UTC Thu Oct 21 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
2130 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is near 37W/38W from 14N southward,
moving westward around 15 kt. Scattered moderate isolated strong
convection is noted from 06N-10N between 30W-40W.

The axis of a tropical wave is over the Lesser Antilles near 61W
south of 18N, moving westward around 15 kt. The wave appears to
enhance convection over NE Venezuela. A few showers are noted over
the Lesser Antilles.

The axis of a tropical wave is near 67W/68W south of 20N, moving
westward around 10 kt. Scattered moderate convection is noted near
the northern end of the wave axis, and also over SW Puerto Rico
and coastal waters.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends off the coast of Guinea from
11N15W to 08N24W to 06N37W. The ITCZ continues from 06N37W to
02N46W. Scattered moderate convection is noted from 06N to 08N
between 15W and 18W, and near 09N50W.

GULF OF MEXICO...

High pressure of 1025 mb centered over the SE United States is
inducing gentle to moderate E winds over the E Gulf with light to
gentle winds elsewhere. Seas are 3-5 ft in the E Gulf and 1-3 ft
in the W Gulf. A surface trough in the SW Gulf of Mexico. Isolated
showers are near the trough axis. An area of showers with embedded
thunderstorms covers the waters N of 26N between 87W and 90W. A
diffluent pattern aloft is helping to induce this convective
activity.

For the forecast, the high pressure ridge will dominate the Gulf
waters during the forecast period. Moderate to fresh easterly
winds are expected over the north-central and NE Gulf today, and
across the SE Gulf into Thu. Gentle to moderate winds will
prevail elsewhere.

CARIBBEAN SEA...

A weak N-S pressure gradient is inducing only gentle to moderate
trades across the Caribbean. Seas are generally 3- 5 ft.
Scattered moderate and isolated strong convection is noted in the
NW Caribbean north of 16N and west of 82W. Similar convection is
also seen over Jamaica and parts of Hispaniola. Upper diffluence
supports this convective activity. A pair of tropical waves are
moving across the eastern Caribbean. Please, see the Tropical
Waves section for more details.

For the forecast, high pressure building N of the area will
bring fresh to locally strong trades E of the Windward Islands
into Sun night. During this period, moderate to fresh winds are
expected over the south-central Caribbean, with winds reaching
locally strong in the Venezuela basin. Gentle to moderate
tradewinds will prevail elsewhere.

ATLANTIC OCEAN...

High pressure of 1025 mb located over southern Georgia extends a
ridge across the SW N Atlantic, the NW Bahamas and Florida. A
cold front extends from 31N52W to 27N59W where it transitions to a
stationary front to 24N67W. Then, a surface trough continues from
24N67W to the central Bahamas. N to NE winds north of the front
are moderate to fresh. Seas peak 8 to 10 ft north of 30N between
58W-62W in NW swell with seas 4-7 ft elsewhere. South of the
front, the E trades are also moderate to fresh with seas 3-5 ft.
Some shower activity is near the frontal boundary. A surface
trough is analyzed just W of the Canary Islands, and extends from
31N19W to 24W19W. This trough is associated with an upper-level
low spinning near 27N21W. A 1028 mb Azores High is driving
moderate to fresh NE to E trades N of the ITCZ. Seas are generally
5 to 8 ft.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021. Ash
emission is on-going. Moderate to high volcanic ash is expected
in the vicinity of the volcano. Elsewhere, ash plume with weak
concentrations drifting northwest. 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, a stationary front from 25N65W to
the central Bahamas will gradually dissipate through Thu. High
pressure building 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.

$$
GR
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