AXNT20 KNHC 232235
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Oct 24 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
An Atlantic tropical wave is near 54W from 16N southward to French
Guiana, moving W around 15 kt. Associated convection is well
inland over French Giana and Suriname.
A Caribbean tropical wave is along 69W from Dominican Republic to
W Venezuela, moving W near 15 kt. Subsidence and drier air aloft
is hindering any significant convection near this wave.
Another Caribbean tropical wave is near 81W from Cuba to Panama,
and moving W around 20 kt. Scattered showers and thunderstorms
note from 11N to 16N between 79W and 85W.
A monsoon trough exits through the African coast near Guinea-
Bissau/Guinea border at 11N15W through a 1011 mb low near 10N16W
to well S of the Cabo Verde Islands at 07N22W. The ITCZ then
continues from 07N22W to 04N47W. Scattered moderate to isolated
strong convection is found near the monsoon trough from 04N to 08N
between 14W to 29W. Scattered showers and isolated thunderstorms
are evident near the low from 09N to 14N between the NW African
coast and 19W. Based on the latest analysis, no significant
convection is present near the ITCZ.
...GULF OF MEXICO...
A 1009 mb low pressure near 21N94W has a surface trough extending
NW to near Tampico, Mexico. A weakening stationary front stretches
from just N of Tampa Bay to near the mouth of the Mississippi
River. Although no significant convection is associated with
either of these features, significant upper-level moisture and
synoptic scale lift is leading to disorganized scattered
convection over a broad area of the central and NW Gulf. Gentle
to moderate winds and seas of 2 to 4 ft are found across much of
the Gulf, except locally fresh winds with seas up to 5 ft near
showers and thunderstorms.
For the forecast, the stationary front will dissipate by tonight.
Gentle to moderate winds will prevail across the basin through
the weekend and become light to gentle by early next week. A
strong cold front is expected to move off the Texas coast on
Wednesday and move across the basin through Thu. Expect fresh to
strong winds and rough seas across the northern and central Gulf
later in the week.
Refer to the Tropical Waves section for details on convection
across the Caribbean Basin. Otherwise moderate to fresh trades
dominate the central and eastern basin, with gentle to moderate
winds in the west. Some locally strong winds are occurring
offshore the South American coast. Seas are 5 to 7 ft in the
central and eastern basin, and 2 to 4 ft in the west.
For the forecast, high pressure N of the area will support fresh
to locally strong trades E of the Windward Islands and across the
eastern Caribbean through Mon night. Winds are also expected to
pulse fresh to strong in the Venezuela basin tonight through Mon
evening. By Tue and Wed, gentle to moderate tradewinds are expect
to prevail across the basin.
A surface trough curves southwestward from SW of Bermuda at 28N71W
across the NW Bahamas to N Cuba. Numerous moderate to isolated
strong convection is noted N of 21N between 62W and 75W. Farther
E, a shear line stretches west- southwestward from well SW of the
Azores across 31N39W to SE of Bermuda at 29N53W. Convection
previously associated with this shear line has dissipated this
afternoon. Surface troughs have formed from 31N36W to 22N39W and
from 31N27W to 25N23W. Refer to the Tropical Waves and Monsoon
Trough/ITCZ sections above for additional convection across the
Moderate trades and seas of 5 to 8 ft are present N of 16N
between the NW African coast and 71W. W of 71W, gentle to moderate
S to SW winds and seas at 3 to 5 ft are seen from the Greater
Antilles northward to 31N. Moderate to fresh NE trades and seas of
8 to 10 ft are found from 05N to 16N between 36W and the Lesser
Antilles. Gentle to moderate with locally fresh winds and seas at
5 to 7 ft prevail for the rest of the basin.
The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Continues ash
emission is noted with small column height. Medium to high
volcanic ash concentration in the vicinity of 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, the surface trough extending across
the northern Bahamas and off the southeast Florida coast will
support convection across the region through tonight. Meanwhile, a
weak stationary front stretches across northern Florida and
adjacent Atlantic waters from 31N78W to 29N81W. This front will
slowly meander southward toward South Florida and dissipate by
Sun. Expect showers and thunderstorms along this boundary through
the rest of the weekend. Moderate to locally fresh winds will
develop off the Florida coast on Sun into Mon near the old