[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 140422
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Oct 14 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
0415 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave has its axis along 33W, south of 18N
and it is moving W at 10-15 kt. A few showers are noted near the
wave axis from 03N and 10N. Dry air is suppressing the storm
activity N of 10N.

Another Atlantic tropical wave has its axis along 54W, south of
17N and it is moving W at 10-15 kt. A few showers are observed
near the wave axis. However, dry air is suppressing the storm
activity N of 11N.

A Caribbean tropical wave has its axis along 69W, south of 20N,
extending from the Dominican Republic to W Venezuela and E
Colombia. The tropical wave is moving W at 10-15 kt. A few showers
are seen near the wave axis, mainly near Hispaniola.

A second Caribbean tropical wave has its axis along 82W, south of
20N and it is moving W at about 10 kt. No deep convection is
noted in association with the wave as it moves into a dry airmass,
except for isolated moderate showers along the wave south of 11N
to Panama, near where the wave intersects the east Pacific monsoon
trough.

...MONSOON TROUGH/ITCZ...

A monsoon trough extends from the coast of Guinea-Bissau near
11N16W to 08N19W. The ITCZ is analyzed from 08N19W to 03N32W, and
then continues from 03N35W to 06N53W. Scattered moderate
convection is present within 300 nm to the north of the ITCZ from
36W to 52W. Isolated moderate convection is found within 150 nm on
both sides of the monsoon trough E of 22W.

...GULF OF MEXICO...

A weak 1018 mb high pressure system centered over the Mid-Atlantic
extends to the Gulf of Mexico. A surface trough is found near the
western coast of Florida and another one extends along 85W from
15N-25N. Only a few shallow showers are seen in association with
these troughs. The rest of the Gulf enjoys fairly tranquil
weather conditions. The pressure gradient between the weak ridge
and lower pressures across the southern United States and the
remnants of Pamela over N Mexico results in fresh to strong SE
winds W of 95W as shown in a recent scatterometer satellite pass
and surface observations. Seas of 4-6 ft are noted W of 94W, with
the highest seas occurring off the S Texas and NE Tamaulipas
coasts. Moderate or weaker winds and seas of 2-4 ft prevail
elsewhere in the Gulf.

For the forecast, high pres extends weakly from the eastern U.S.
southwestward to the N central Gulf and will influence the Gulf
waters during the next several days. Moderate to fresh southerly
winds are expected over the western Gulf between the ridge and
lower pressure over the Southern Plains and northern Mexico
through Thu. Gentle to moderate breezes will persist elsewhere
through Fri. A cold front enter the NW Gulf Fri night with fresh
to strong northerly winds following it. The front will reach
central Florida to western Bay of Campeche Sun morning with
moderate to fresh N to NE winds across most of the Gulf..

...CARIBBEAN SEA...

A sharp upper level trough and upper level low in the NW Bahamas
near 24N76W is enhancing the development of showers and
thunderstorms to the east of a surface trough that extends from
the NE Caribbean to well north of the Leeward Islands. The large
area of convection is mainly N of 15N and E of 67W. These storms
are affecting parts of Puerto Rico and the Virgin Islands. Recent
scatterometer data indicate that fresh to strong southerly winds
are occurring in association with the strongest convection.
Moderate or weaker winds prevail in the rest of the basin. The
exception are locally fresh trades noted in between Cuba and
Jamaica and within 60 nm of the central coast of Cuba. Seas of 3-5
ft are found E of 77W, likely closer to 6 ft in the NE Caribbean
passages due to the northerly swell from the Atlantic. Seas of 1-3
ft are prevalent elsewhere in the Caribbean.

For the forecast, a vigorous upper level trough from the Bahamas to the
NW Caribbean will support active weather across the central
Caribbean and extreme NE Caribbean through tonight behind two
tropical waves. Northerly swell will subside across the regional
Atlc and Caribbean passages tonight. Low pres NE of the southern
Bahamas will drift E-NE tonight through Thu then accelerate NE
into the weekend. This will weaken the pressure gradient across
the Caribbean basin leading to tranquil marine conditions.

...ATLANTIC OCEAN...

The previously mentioned upper level low in the NW Bahamas
continues to interact with a couple of surface troughs further to
the east, producing a large area of showers and thunderstorms. One
of the troughs extends from 29N67W to a 1009 mb low pressure near
25N75W to the coast of N Hispaniola. The other surface trough
extends from 26N60W to 16N67W. Scattered moderate to isolated
strong convection is found from the NE Caribbean to 29N and
between 60W and 67W. Recent scatterometer satellite data indicate
that fresh to strong southerly winds are found with the strongest
convection.

The other feature of interest is a cold front that extends from a
1002 mb low pressure system north of our area, entering the
tropical Atlantic near 31N40W and continues SW to 27N46W and then
NW to 31N58W. Scattered moderate convection is noted 150 nm to the
south of the frontal boundary between 36W and 46W. Satellite-
derived wind data depict a large area fresh and strong cyclonic
winds N of 24N and between 31W and 48W. The rest of the tropical
Atlantic is dominated by a weak ridge centered near the Madeira
islands, permitting fairly tranquil weather conditions and
moderate or weaker winds.

A widespread northerly swell continues to affect the north-central
tropical Atlantic with seas of 8-12 ft, mainly N of 25N and
between 33W and 55W. Seas of 4-7 ft are found W of 60W, while seas
of 6-9 ft are noted S of 25N and W of 30W. Finally, seas of 5-8 ft
are present E of 30W.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021.
Significant volcanic ash is possible near the volcano. 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 W of 65W, high pressure extending across the
area will shift slowly E and weaken through the end of the week.
Developing low pres 1009 mb near 24N70W will begin to drift E-NE
tonight and Thu then accelerate E-NE and exit the area Fri. This
system will continue to produce very active weather and impact the
regional waters through Fri. Northerly swell across the regional
waters will subside through tonight. A cold front will move
southward across Florida by the end of the weekend, bringing fresh
northerly winds in the Atlc waters.

$$
DELGADO
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