AXNT20 KNHC 250538
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Mon Oct 25 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
An Atlantic tropical wave is E of the Cabo Verde Islands near 22W
from 16N southward, moving W at around 10 kt. Scattered showers
are present in the vicinity of the wave axis.
Another Atlantic tropical wave is moving across the Windward
Islands near 60W from 16N southward into Venezuela, moving W at
10 to 15 kt. Aided by an upper-level trough in the vicinity,
scattered moderate to convection is occurring from the coast of
Guayana and NE Venezuela to 13N between 56W and 63W.
A Caribbean tropical wave east of Jamaica is along 75W from the
Windward Passage into Colombia, moving W at around 15 kt.
Convection previously associated with this wave has moved well
inland into Colombia.
Another tropical wave, which mainly extends into the eastern
Pacific stretches northward into the Gulf of Honduras and the
Yucatan Peninsula. Its axis is moving W at 10 to 15 kt. All
associated convection is now in the eastern Pacific.
A monsoon trough exits through the African coast at Guinea-Bissau
near 10N15W to 07N24W. The ITCZ then continues from 07N24W to
02N51W. Scattered moderate convection is evident near the monsoon
Trough near along the African coast extending from Senegal to
Sierra Leone and along the ITCZ between 29W and 44W.
...GULF OF MEXICO...
A broad area of scattered moderate to isolated strong convection
associated with this trough extends N of 23N and E of 90W. E of
88W, scattered moderate isolated strong convection extends
across the Florida Peninsula. This is mainly associated to
significant upper-level moisture and synoptic scale lift which is
leading to this disorganized convection. Except near the
thunderstorm activity, mainly gentle SE wind prevails across the
basin with seas of 3 to 5 ft.
For the forecast, a ridge will dominate the Gulf waters producing
light to gentle winds Mon and Tue. Fresh to strong southerly
winds will develop in the NW Gulf Tue night into Wed ahead of a
cold front expected to push off the Texas coast on Wed. The front
will move across the Gulf region through Thu night. Fresh to
strong winds are expected ahead and behind the front, with
building seas to 10-12 ft in the wake of the front.
Refer to the Tropical Waves section for details on convection
across the Caribbean Basin. While drier air is suppressing
convection development across much of the basin, patches of
moisture is enhancing some shallow showers across the central
and western Caribbean this evening. Otherwise, moderate to fresh
trades with seas of 5 to 7 ft dominate the central Caribbean
while seas in the eastern Caribbean have subsided to 3 to 4 ft.
Mainly moderate trades and seas at 3 to 5 ft prevail elsewhere.
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 through Mon night.
Gentle to moderate trade winds are expected to prevail across the
basin from Tue through Thu. A cold front is expected to reach the
NW Caribbean Thu night into Fri morning.
A surface trough extends from SW of Bermuda through NW Bahamas
into the Florida Straits. Scattered moderate convection is noted
in association with this trough N of 24N between 64W and along
the eastern coast of Florida. Further east, another trough
extends from 27N41W to 20N44W. Scattered showers are noted in the
vicinity of the trough axis. Most of the eastern Atlantic is under
the influence of a 1031 mb high pressure north of the area.
Mainly moderate winds and seas of 5 to 6 ft dominate N of 16N
between 56W and the African coast. S of 16N to the ITCZ, moderate
to fresh NE to E trades and seas of 6 to 8 ft prevail. W of 70W,
moderate SE winds are increasing, and seas are 3 to 5 ft.
The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Ash clouds
and some SO2 have been emitted periodically from 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, A non-tropical low-pressure system is
expected to form off the east coast of the United States during
the next couple of days. The frontal low will move generally
north-northeastward through the middle of the week, and the
system could bring rain and wind impacts to portions of the mid-
Atlantic and northeast U.S. coast. The associated cold front will
move eastward across the northern forecast waters Mon. Fresh to
strong southerly winds and building seas are expected ahead of the
front. Another cold front will push off NE Florida coast on Tue,
and bring more fresh to strong winds across the waters N of 27N. A
third cold front is expected to sweep across the region Thu night
through Fri night, bringing another round of fresh to strong
winds north of the Bahamas.