[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231020
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Aug 23 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

At 23/0300 UTC, the last advisory was issued by the National
Hurricane Center on Henri. At 23/0900 UTC, Tropical Depression
Henri is centered near 41.6N 74.4W or 50 nm NNW of New York City
moving E at 1 kt. Estimated minimum central pressure is 1005 mb.
Maximum sustained wind speed is 25 kt with gusts to 35 kt. Henri
is expected to produce additional rainfall of 1 to 3 inches, with
locally higher amounts possible, over portions of Long Island, New
England, southeast New York, New Jersey, and eastern Pennsylvania
through today. Heavy rainfall from Henri will continue to result
in limited to considerable flash, urban, and small stream flooding
impacts, along with minor to isolated moderate river flooding.
Swells are expected to continue across much of the east coast of
the U.S. and Atlantic Canada through today. These swells could
cause life-threatening surf and rip current conditions.

For the latest rainfall reports and wind gusts associated with
Tropical Depression Henri see the following link:
https://www.wpc.ncep.noaa.gov/discussions/nfdscc3.html

...TROPICAL WAVES...

A tropical wave is along 20W, from 19N southward. The wave is
moving W at 10 to 15 knots. Scattered moderate convection is
ahead of the wave axis from 05N-08N between 20W-23W.

A well defined tropical wave is along 35W, from 20N southward.
The wave is moving W at 10 knots. A 1011 mb low pressure is
analyzed along the wave axis near 13N. Disorganized shower
activity is associated with this low. Little, if any, development
is expected to occur during the next couple of days. Some gradual
development, however, is possible by the middle to latter part of
the week as the system moves northwestward at 10 to 15 mph over
the central Atlantic. The latest Tropical Weather Outlook gives
this system a low chance of tropical cyclone formation through 5
days. Recent satellite derived wind data provided observations of
fresh to strong winds on the E side of the low center.

A weak tropical wave is along 50W, from 20N southward. The wave
is moving W 10 to 15 knots. Convection is limited near the wave
axis.

An active tropical wave is moving across the eastern Caribbean.
Its axis is along 63W and extends from the northern Leeward
Islands into eastern Venezuela. The wave is producing scattered
showers and thunderstorms, particularly from 10N-15N between 55W-
68W. This convective activity is affecting the Windward Islands
and regional waters. The wave is also enhancing scattered showers
and thunderstorms over eastern Venezuela. Fresh to strong NE
winds are noted per scatterometer data ahead of the wave axis. The
wave will reach the Mona Passage tonight, but the associated
moisture is forecast to remain well south of Puerto Rico.

A second tropical wave is over the Caribbean Sea along 80W from 20N
southward, moving westward 10 to 15 knots. Scattered moderate
convection is near the southern end of the wave axis from 10N-13N
between 78W-82W. Similar convection is across eastern plains of
Nicaragua.

Another tropical wave is over the Yucatan peninsula crossing near
the Belize/Guatemala border into El Salvador. The wave is helping
to induce convection over parts of Belize, Guatemala and El
Salvador.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Mauritania near
17N16W to a 1011 mb low pressure located near 13N35W to 08N52W.
Most of the convective activity across the area is associated
with the aforementioned tropical waves.

...GULF OF MEXICO...

High pressure dominates the Gulf waters producing mainly gentle to
moderate winds. Seas are generally below 4 ft based on recent
altimeter pass. A 1017 mb high pressure center is noted over the
NE Gulf near 27N87W. Small area of showers and thunderstorms is
over the Bay of Campeche near 20N94W.

High pressure will remain in control of the weather pattern across
the Gulf waters through Fri. Fresh to possibly locally strong
winds will pulse west of the Yucatan Peninsula tonight and again
Tue night due to local effects associated with a thermal trough.
Looking ahead, marine conditions may deteriorate over the SW Gulf
during the upcoming weekend as a tropical system move across the
region.

...CARIBBEAN SEA...

Two tropical waves are moving westward across the Caribbean Sea.
Please, see the Tropical Waves section for details.

The most recent scatterometer data show fresh to strong winds
across the central Caribbean, and in the Gulf of Honduras with
seas to 8 ft near the coast of Colombia. Convection across the
basin are related to the tropical waves.

The aerial extent of the trade winds will increase over the next
24 hours covering most of the waters S of 17N and E of 80W. As a
result, fresh to strong trade winds are expected over the east and
central Caribbean through midweek, with building seas of 8 to 10
ft. Fresh to locally strong winds and seas to 8 ft are also
expected in the Windward passage through Tue night.

...ATLANTIC OCEAN...

Tree tropical waves are moving westward between the W coast of
Africa and the Lesser Antilles. Please, see the Tropical Waves
section for details.

High pressure of 1022 mb is located just E of Bermuda near 32N62W.
Another 1022 mb high pressure is centered about midway between
the Azores and the Madeira Islands. These systems dominate the
Atlantic forecast waters where gentle to moderate winds are noted.
Fresh to locally strong winds area between the W coast of Africa
and the Canary Islands as well as from 18N-26N E of 21W to the
coast of Africa.

The northern extent of the tropical wave located near 35W is
forecast to break-up and move northwestward as a trough across
the Atlantic waters. An area of fresh to strong E-SE winds will
follow the trough allowing seas to build to 10-12 ft. This trough
is forecast to approach the SW N Atlantic by Thu.

For the forecast W of 65W: High pressure located near Bermuda
will dominate the forecast region through at least Wed. A surface
trough is forecast to approach from the E on Thu, possible
reaching the NE waters on Fri. Fresh to locally strong winds are
expected N of Hispaniola including the approaches to the Windward
Passage through Tue night. The pressure gradient could increase
some across the SW N Atlantic Tue night into Wed between high
pressure located just N of Bermuda and the approaching surface
trough.

$$
GR
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