[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211630
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Aug 21 2022

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 1200 UTC surface analysis and satellite imagery through
1610 UTC.

...TROPICAL WAVES...

An eastern Atlantic tropical wave extends its axis along 25/26W
from 09N-22N, moving west at 15 kt. Scattered moderate convection
is noted within 180 nm W and 60 nm E of the wave axis from
14N-18N. Scattered showers are within 300 nm W of the wave axis
from 08N-12N. Recent altimeter data near this wave show seas of
7-8 ft from 06N-15N between 22W-28W. This system has a low chance
of tropical cyclone development within the next five days as it
continues moving westward to west-northwestward at a similar
forward speed.

A central Atlantic tropical wave extends its axis along 45/46W
from 07N-21N, moving west at 15 to 20 kt. Scattered moderate
convection is noted within 60 nm of the wave axis from 07.5N to
09.5N, near where the wave axis intersects the monsoon trough.

A central Caribbean tropical wave extends its axis along 75W from
eastern Cuba to central Colombia, moving west at 10 to 15 kt.
Scattered showers and tstorms between Jamaica and the Windward
Passage are being enhanced by an upper-level low located N of the
southeast Bahamas. Numerous moderate scattered strong convection
located west of the wave axis, in the southwest Caribbean S of 12N
between 75.5W-82W, is mainly due to the east Pacific monsoon
trough.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Mauritania near 19.5N16.5W to the Cabo Verde Islands near 15N24.5W
to 08.5N40W to 08N47W. The ITCZ continues from 08N47W to 07N55W
to 11N61W. Scattered moderate and isolated strong convection is
noted along and south of the monsoon trough from 04N-10N between
33.5W-44W. Similar convection is noted within 60 nm either side of
the ITCZ between 57.5W-62W from 08N-12N.

GULF OF MEXICO...

The remnants of PTC Four have dissipated more than 120 nm inland
from the coastline, along the Texas/Mexico border. However, some
scattered showers and isolated tstorms are noted offshore the
Texas and Louisiana coasts, due to the high amount of water vapor
in the low to mid levels, as seen in CIRA LPW imagery. Abundant
cloud cover with isolated showers are noted elsewhere over the
northern Gulf, north of 28N between SE Louisiana and Destin,
Florida.

Deep-layered ridging extends from west to east across the northern
Gulf of Mexico. At the surface, this ridge runs along 30N. A 1020
mb high pressure is analyzed near Apalachicola, Florida. Upper-
level troughing prevails over the Yucatan and south-central Gulf.
This, combined with a weak surface trough to the W of South
Florida, is triggering isolated showers and tstorms from
23N-26.5N between 83W-87.5W.

A recent ASCAT satellite wind data pass shows moderate E winds in
the Straits of Florida, where seas are likely 3-4 ft. Moderate to
locally fresh SE-SSE winds and seas of 5-6 ft are occurring off
the coasts of Texas and northeastern Mexico. NOAA buoy 42020 near
27.0N 96.7W, which had been reporting seas of 7-8 ft earlier this
morning, is now reporting seas of 6 ft. Light to gentle
anticyclonic winds prevail over the NE Gulf near the high pressure
center, with seas 1-2 ft.

For the forecast, winds and seas continue to diminish over the
northwest Gulf as high pressure builds across the northern Gulf.
The weak ridging will prevail over the Gulf through the forecast
period, leading to gentle to moderate winds and slight seas.

CARIBBEAN SEA...

Refer to the tropical waves section above for details on the
tropical wave moving across the basin and on the convection in the
SW Caribbean associated with the east Pacific monsoon trough.

Upper-level troughing is present over the Yucatan Peninsula and
far NW Caribbean, enhancing isolated thunderstorms between the
Cayman Islands and the Yucatan Peninsula. Another cluster of
scattered thunderstorms is located from 14N-16N between 77W-82W.
An upper-level low located N of the southeast Bahamas extends an
upper-level trough southward to near Hispaniola. Upper-level
diffluence to the south of Hispaniola is enhancing a cluster of
scattered moderate convection from 15N-18N between 66W-72W.
Scattered showers and isolated tstorms in the far SW Caribbean,
south of 13N and east of 64.5W, are related to the ITCZ.

A recent ASCAT pass shows fresh to locally strong E winds just S
of Hispaniola from 16.5N-18N between 71W-73W. Moderate or weaker
winds prevail across much of the remainder of the basin, except
for locally fresh NE winds in the lee of Cuba between 78W-81W.
Buoy and altimeter data from the past few hours indicate that seas
are 4-6 ft across the central Caribbean. Seas of 3-4 ft prevail
elsewhere, except likely 2-3 ft in the Gulf of Honduras.

For the forecast, surface ridging north of the area will continue
to support moderate to fresh trade winds in the eastern and
central Caribbean through the forecast period, while gentle to
moderate winds will prevail across the western Caribbean. Fresh to
locally strong NE winds are expected across the Windward Passage
tonight.

ATLANTIC OCEAN...

An upper-level low centered N of the southeast Bahamas near
25N72W is inducing scattered thunderstorms from 25N-30N between
64W-74W. Another upper-level low is centered farther east, near
24N57W. A surface trough is in the same area, extending along 57W
from 23N-31N. Scattered showers and isolated tstorms are noted
from 22N-28N between 53W-59W.

A surface ridge extends WSW from a 1023 mb high pressure centered
near 32N68W to northern Florida. Over the western Atlantic, ASCAT
shows gentle winds north of 27N with moderate trade winds to the
south of 27N. An altimeter pass from this morning at 21/1030 UTC
along 75/76W observed seas 2-3 ft north of 28N, and 4-5 ft to the
south, with up to 6 ft in the Windward Passage. Seas are also
likely 5-6 ft to the east of the southeast Bahamas.

In the eastern half of the Atlantic, broad ridging prevails to the
north of the tropical waves, with mostly moderate trade winds and
4-7 ft seas. The exception is the far NE part of the area, between
the Canary Islands and the coast of Morocco, where fresh to
locally strong N to NE winds are occurring along with seas of 6 to
9 ft.

For the forecast west of 55W, the subtropical surface ridge
extending from Bermuda to northern Florida will support moderate
to fresh easterly winds south of 22N through the early part of
this week. A weak surface trough will move westward from 65W to
75W on Mon. The trough will weaken the ridge, allowing winds to
diminish by mid week.

$$
Hagen
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