[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251022
TWDAT

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

...SPECIAL FEATURE...

Heavy Rainfall in southern Central America: A broad area of low
pressure is expected to form over the SW Caribbean Sea later this
week, resulting in an increase in moisture and unstable conditions
across southern Central America. Heavy rainfall is expected
across eastern Nicaragua, Costa Rica, Panama, and NW Colombia
through early in the weekend. The heaviest precipitation is
forecast to affect southern Costa Rica and western Panama late
this week. These rains could cause significant flooding and
mudslides in some areas. Please, monitor the latest forecasts for
your local or national meteorological service.

...TROPICAL WAVES...

The axis of a tropical wave is near 31W, south of 19N, moving W
at 10 to 15 kt. A 1008 mb low pressure is along the wave axis
near 10N31W. Scattered moderate to isolate strong convection is
noted NW of the low center from 12N to 15N between 31W and 35W.
Some development of this system is possible over the next several
days while it moves west-northwestward at 10 to 15 kt over the
eastern tropical Atlantic. Upper-level winds are forecast to
become less conducive for development by this weekend. For more
details, please see the latest Tropical Weather Outlook.

The axis of a tropical wave is near 51W, south of 19N, moving W
at 10 to 15 kt. There is no significant convection associated to
this wave.

The axis of a tropical wave is near 72W, south of 20N, moving W
at 10 to 15 kt. A 1006 mb low pressure is along the wave axis near
13N72W. Clusters of moderate to isolated strong convection are
noted on the west side of the low center, particularly from 11N
to 14N between 72W and 74.5W. This convective activity is affecting
the Guajira peninsula in Colombia. This disturbance is being
monitored for possible tropical cyclone development over the
western Caribbean Sea in a couple of days. For more details,
please see the latest Tropical Weather Outlook.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean through Senegal near
14N17W and continues to 10N31W to 05N35W. The ITCZ then extends
from 05N35W to 07N48W. Aside from convection noted in the tropical
waves section, scattered moderate isolated strong convection is
observed within 90-120 nm of the coast of Africa from 04N to 11N.
This convective activity is likely ahead of the next tropical
wave approaching the W coast of Africa.

...GULF OF MEXICO...

High pressure continues to dominate the weather conditions across
the Gulf of Mexico. A surface trough in the northern Gulf extends
from the Florida Panhandle to 28N92W. Scattered showers and
isolated thunderstorms are seen along the trough axis. Light to
gentle winds are noted over the northern Gulf waters, mainly N of
27N with gentle to moderate winds prevail elsewhere. Seas are in
the 3-5 ft range over the SE Gulf, and in the eastern Bay of
Campeche with seas of 1-3 ft elsewhere.

For the forecast, a surface trough will move into the eastern
Gulf tonight into Thu morning, bringing fresh NE to E winds.
Otherwise, high pressure pressure will dominate the basin through
Fri, producing mainly gentle to moderate E to SE winds. Fresh
winds will pulse west of the Yucatan Peninsula tonight and again
Thu night. A broad area of low pressure is expected to form over
the western Caribbean Sea in a couple of days. Environmental
conditions are forecast to be conducive for development, and a
tropical depression is likely to form late this week or this
weekend while the system moves northwestward over the northwestern
Caribbean Sea, near or across the Yucatan Peninsula of Mexico,
and into the western Gulf of Mexico by Sunday. Based on the
forecast, expect increasing winds and seas across the Gulf waters
during the upcoming weekend.

...CARIBBEAN SEA...

Satellite derived wind data indicate fresh to strong trade winds
across the central Caribbean, and fresh to locally strong winds in
the Windward passage, and in the Gulf of Honduras. Moderate to
fresh winds are noted elsewhere. Seas are in the 6-9 ft range
across the central Caribbean, but mainly between 70W and 75W.
Seas are in the 3-4 ft range over the NE Caribbean, and 4-6 ft
elsewhere. Clusters of moderate to strong convection are over the
SW Caribbean, mainly S of 12N, in association with the eastern
Pacific monsoon trough, that extends from northern Colombia to
Costa Rica.

For the forecast, fresh to locally strong trade winds will dominate
most of east and central Caribbean today. A broad area of low
pressure is expected to form over the western Caribbean Sea in a
couple of days from a tropical wave currently located over the
central Caribbean Sea along 72W. Environmental conditions are
forecast to be conducive for development, and a tropical depression
is likely to form late this week or this weekend while the system
moves northwestward over the northwestern Caribbean Sea, and near
or across the Yucatan Peninsula of Mexico. Based on the forecast,
winds and waves will likely increase between 77W and the Yucatan
Peninsula Fri and Sat.

...ATLANTIC OCEAN...

A surface trough is E of the Bahamas S of 28N along 71W. This
trough is a reflexion of an upper-level low that is moving
westward. Scattered showers and thunderstorms are associated with
the trough and cover the waters from 24N to 28N between 70W and
80W. Moisture related to this trough will reach South Florida by
this afternoon increasing the likelihood of showers and
thunderstorms. Fresh to strong NE winds are ahead of the trough
axis over the central Bahamas and the Old Bahama Channel reaching
the coast of Cuba. Seas of 8-9 ft are associated with these winds
E of the Bahamas.

For the forecast W of 65W: the surface trough located along 71W
will reach the NW Bahamas this evening and move into the eastern
Gulf of Mexico late tonight into Thu morning. Fresh to strong NE
winds are expected ahead of the trough axis. Otherwise, high
pressure located just N of the forecast region will dominate the
SW N Atlantic through Sat. Fresh to locally strong winds are
expected to pulse N of Hispaniola during the evening hours through
Sat night.

A broad trough of low pressure remains over the central Atlantic
and extends from 31N50W to 21N52W. Fresh to strong SE winds are
noted per scatterometer data on the E side of the trough axis. A
low pressure is analyzed along the trough near 25N52W. This
system is producing disorganized showers and thunderstorms over
the waters N of 25N between 50W and 53W. Only slow development of
this system is expected during the next day or so due to
unfavorable upper-level winds. Afterwards, environmental
conditions are expected to become more conducive for development,
and a tropical depression is likely to form late this week or this
weekend while the system turns eastward over the central Atlantic.
For more details, please see the latest Tropical Weather Outlook.

The remainder of the Atlantic forecast waters is under the influence
of a ridge. The pressure gradient between the ridge and lower pressures
near the monsoon trough supports an area of moderate to fresh NE
to E winds roughly from 15N to 25N E of 40W, and between the Canary
Islands and the coast of Morocco and Western Sahara.

$$
GR
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