Tropical Weather Discussion
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551
AXNT20 KNHC 202120
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0015 UTC Thu Aug 21 2025

Tropical Weather Discussion for North America, Central America
Gulf of America, 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
2100 UTC.

...SPECIAL FEATURES...

Hurricane Erin is centered near 31.2N 73.6W at 20/2100 UTC or
450 nm W of Bermuda, moving N at 12 kt. Estimated minimum
central pressure is 943 mb. Maximum sustained wind speed is 95
kt with gusts to 115 kt. Peak seas are near 48 ft near the
center. Seas 8 ft or greater are covering much of the discussion
waters N of 23N and W of 65W. Numerous moderate to strong
convection is noted from 29N to 32N between 71W and 74W. Numerous
moderate and scattered strong convection is elsewhere from 25N to
37N between 66W and 77W. Erin will move northward between Bermuda
and the U.S. east coast over the next day or so. After that, the
system should accelerate northeastward and east- northeastward.
Swells generated by Erin will affect the Bahamas, Bermuda, the
east coast of the United States, and Atlantic Canada during the
next several days, producing life-threatening surf and rip
currents along the beaches during the next several days.
Beachgoers in those areas should follow advice from lifeguards,
local authorities, and beach warning flags.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Erin
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Eastern Tropical Atlantic (AL99):
Satellite-derived surface wind data from earlier today revealed
that a concentrated area of showers and thunderstorms located
several hundred miles southwest of the Cabo Verde Islands lacks a
closed surface circulation. Environmental conditions appear
marginally favorable for additional development over the next day
or so while the system moves west-southwestward at around 15 mph
and a short-lived tropical depression could form. By the end of
the week, environmental conditions are expected to become
unfavorable for further development.

...TROPICAL WAVES...

A tropical wave has its axis near 30W from 05N to 19N, moving
westward at about 15 kt. Numerous moderate to strong convection is
seen from 07N to 14N between 27W and 35W. Environmental
conditions appear marginally favorable for additional development
over the next day or so while the system moves west-southwestward
at around 15 mph and a short-lived tropical depression could form.
By the end of the week, environmental conditions are expected to
become unfavorable for further development. This system (AL99)
has a medium chance of becoming a tropical cyclone during the next
48 hours.

An central Atlantic tropical wave has its axis near 46W from
05N to 21N, moving westward around 15 kt. The wave is producing a
broad area of disorganized showers and thunderstorms. Environmental
conditions appear conducive for gradual development of this
system, and a tropical depression could form by this weekend while
it moves near or to the north of the northern Leeward Islands.
This system has a low chance of becoming a tropical cyclone in the
next 48 hours and a medium chance of becoming a tropical cyclone
in the next 7 days.

A Caribbean tropical wave Caribbean Sea has its axis near 70W S of
20N, moving westward at 10 to 15 kt. No significant convection is
present with the wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic near 20N17W, and extends
to 11N29W and to 15N41W. Aside from convection noted in the
tropical waves section above, scattered moderate convection is
noted from 14N to 19N between 36W and 41W.

...GULF OF AMERICA...

A weak pressure gradient is resulting in light to gentle winds
and 1 to 2 ft seas across the entire basin.

For the forecast, moderate to locally fresh NE to SE winds will
be possible over the south-central Gulf each afternoon and evening
through this weekend as a trough develops over the Yucatan
Peninsula and moves westward. Otherwise, gentle to locally
moderate winds and slight seas will prevail over the remainder of
the basin as weak high pressure dominates the region.

...CARIBBEAN SEA...

A more typical tradewind pattern is returning to the Caribbean as
Hurricane Erin moves further northward and a ridge builds N of the
area. Moderate to fresh winds are over the south central
Caribbean with moderate winds elsewhere E of 75W. Light to gentle
winds are over the waters W of 75W. Seas are in the 5-6 ft range
over the south central Caribbean and 3-5 ft elsewhere E of 75W.
Seas of 1-2 ft prevail W of 75W.

For the forecast, fresh to locally strong trade winds and locally
rough seas are expected over the central and eastern Caribbean
tonight through Fri as a strengthening pressure gradient develops
between low pressure over Colombia and building high pressure in
the wake of Hurricane Erin in the western Atlantic. Elsewhere,
fresh to occasionally strong E to SE winds will pulse in the Gulf
of Honduras Thu through this weekend. A tropical wave located
several hundred miles east of the Leeward Islands will encounter
environmental conditions conducive for gradual tropical
development, and a tropical depression could form by this weekend
while it moves near or to the north of the northern Leeward
Islands. There is a low chance of development within the next 48
hours, and a medium chance within the next 7 days.

...ATLANTIC OCEAN...

Please see the Special Features section for information on
Hurricane Erin.

Seas greater than 8 ft, and winds 20 kt or greater associated with
Erin are covering the waters N of 23N and W of 65W. Elsewhere, a
frontal boundary enters the area near 31N41W and extends to
29N50W. Scattered moderate convection is in the vicinity of the
boundary. Moderate winds, and seas of 6 ft, are in the vicinity of
the frontal boundary. Elsewhere, high pressure ridging dominates
the waters E of 60W. Gentle to moderate winds, and seas of 5-8 ft,
generally prevail elsewhere.

For the forecast, Erin is centered just N of the area, and will
continue to shift further away from the forecast waters. Swells
generated by Erin will affect the Bahamas, Bermuda, and the east
coast of the United States during the next several days. A
tropical wave located several hundred miles east of the Leeward
Islands will encounter environmental conditions conducive for
gradual tropical development, and a tropical depression could form
by this weekend while it moves near or to the north of the
northern Leeward Islands. There is a low chance of development
within the next 48 hours, and a medium chance within the next 7
days. Elsewhere, a tropical wave located several hundred miles
southwest of the Cabo Verde Islands will encounter environmental
conditions marginally favorable for additional tropical
development over the next day or so while the system moves west-
southwestward at around 15 mph and a short- lived tropical
depression could form. By the end of the week, environmental
conditions are expected to become unfavorable for further
development. There is a medium chance of development within the
next 48 hours and the next 7 days.

$$
AL