[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260601
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Aug 26 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
0540 UTC.

...SPECIAL FEATURES...

Shower and thunderstorm activity gradually is becoming better
organized in association with a trough of low pressure located a
couple hundred miles south of Jamaica. While recent satellite wind
data indicate that the system does not yet have a well-defined
circulation, environmental conditions remain conducive for
additional development, and a tropical depression is expected to
form later today or tomorrow. The system is forecast to move
northwestward over the northwestern Caribbean Sea later today,
near Cuba and the Yucatan Peninsula of Mexico on Friday, and into
the Gulf of Mexico this weekend. Regardless of development, heavy
rainfall and flooding will be possible through the weekend in
portions of Central America, the Yucatan Peninsula, Jamaica, the
Cayman Islands, and Cuba. In addition, this system could bring
dangerous impacts from storm surge, wind, and heavy rainfall to
portions of the coasts of Louisiana, Texas, and the Mexican state
of Tamaulipas late this weekend and early next week. However,
uncertainty remains large since the system has yet to form.
Interests in these areas should closely monitor the progress of
this system and ensure they have their hurricane plan in place. An
Air Force Reserve reconnaissance aircraft is scheduled to
investigate the system later today, if necessary. The chance of
formation chance through 48 hours is high. Precipitation: numerous
strong is from 110 nm to 300 nm of a 1005 mb low pressure center,
in the NE quadrant. The 1005 mb low pressure center is along a
77W tropical wave, near 14N. Isolated moderate to locally strong
is elsewhere from 20N southward from 70W to the line that runs
from E Honduras to SE Cuba.

A broad trough of low pressure is producing disorganized showers and
thunderstorms in the central tropical Atlantic Ocean, about 650
miles to the east-southeast of Bermuda. The environmental
conditions are forecast to be generally conducive for development.
It is likely for a tropical depression to form late this week or
this weekend, while the system moves slowly northeastward through
the central Atlantic. The chance of formation through 48 hours is
medium.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 19W, from 18N southward,
moving westward 10 to 15 knots. This wave just was added to the
analysis at 26/0000 UTC. Precipitation: widely scattered moderate
to isolated strong is within 270 nm to the west of the tropical
wave from 11N to the southern part of the Cabo Verde Islands, and
from 75 nm to the west of the tropical wave to 260 nm to the east
of the tropical wave from 06N to 09N.

An Atlantic Ocean tropical wave is along 36W/37W, from 18N
southward, moving westward 10 to 15 knots. A 1008 mb low pressure
center is along the wave near 11.5N. Precipitation: widely
scattered moderate to isolated strong is from 07N to 09N between
29W and 31W, and within 340 nm of the 1008 mb low pressure center
from the NE quadrant to the W quadrant. Some development of this
system is possible during the next several days, while it moves
west-northwestward 10 to 15 mph through the eastern tropical
Atlantic Ocean. The upper level winds are forecast to become less
conducive for development by early next week.

An Atlantic Ocean tropical wave is along 57W, from 19N southward,
moving W 10 to 15 knots. Precipitation: no significant deep
convective precipitation is apparent in satellite imagery.

A tropical wave is along 92W/93W, from 17N in the Isthmus of
Tehuantepec of southern Mexico, moving westward 10 to 15 knots.
Precipitation: widely scattered moderate to isolated strong is
within 215 nm to the west of the tropical wave from 14N to 17N
including in the Isthmus of Tehuantepec of southern Mexico.
Isolated moderate is within 300 nm to the east of the tropical
wave from 12N to 15N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal border sections of
Mauritania and Senegal, to the 1008 mb low pressure center that is
along the 36W/37W tropical wave, to 08N40W and 08N47W. The ITCZ
continues from 08N47W, to 10N61W just to the south of Trinidad.
Precipitation: widely scattered moderate to isolated strong is
within 125 nm to the south of the monsoon trough between 38W and
47W, and within 60 nm to the south of the ITCZ between the 57W
tropical wave and 61W.

...GULF OF MEXICO...

Upper level cyclonic wind flow covers most of the eastern half of
the Gulf of Mexico. A surface trough passes through southern
Louisiana. Precipitation: isolated moderate rainshowers span the
Gulf of Mexico.

A broad surface ridge extends from the NE corner of the area to
the SW corner of the Gulf of Mexico, to the coast of Mexico near
20N.

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
during the next day or so from a tropical wave currently located
north of Colombia. Environmental conditions are forecast to be
conducive for development, and a tropical depression or tropical
storm is likely to form late this week or over the weekend. The
system is expected to move northwestward over the northwestern
Caribbean Sea and near or across the Yucatan Peninsula of Mexico
on Friday and into the Gulf of Mexico this weekend, where
conditions are expected to be favorable for additional
development. Mariners should closely monitor the progress of this
system. It has potential for significant strengthening in the Gulf
of Mexico. Expect a large increase in winds and seas this weekend
in association with this system.

...CARIBBEAN SEA...

Upper level cyclonic wind flow covers the Caribbean Sea to the
northwest of the 77W tropical wave.

The eastern extension of the eastern Pacific Ocean monsoon trough
is along 10N/11N from 74W in Colombia, beyond Costa Rica, and
into the eastern Pacific Ocean. Precipitation: scattered strong is
along the coast/in the coastal plains of SE Nicaragua and NE Costa
Rica. Widely scattered moderate to isolated strong is elsewhere
from 15N southward from 80W westward.

A broad area of low pressure is expected to form over the western
Caribbean Sea during the next day or so from a tropical wave
currently located along 77W north of Colombia. Environmental
conditions are forecast to be conducive for development, and a
tropical depression or tropical storm is likely to form late this
week or over the weekend. The system is expected to move
northwestward over the northwestern Caribbean Sea and near or
across the Yucatan Peninsula of Mexico on Friday and into the Gulf
of Mexico this weekend, where conditions are expected to be
favorable for additional development. Based on the forecast, winds
and waves will likely increase over the NW Caribbean Thu night
through Sat.

...ATLANTIC OCEAN...

A NE-to-SW oriented surface trough is passing through the
Bahamas, anywhere from 90 nm to 270 nm to the east of Florida.
The southern half of the surface trough passes through central
Cuba, into the NW corner of the Caribbean Sea near 18N85W.
Precipitation: widely scattered moderate to isolated strong is
within 300 nm to the west of the surface trough, in Florida and in
the easternmost parts of the Gulf of Mexico. Isolated moderate to
locally strong is within 440 nm to the east of the surface trough.
Broad upper level cyclonic wind flow is co-located with the
surface trough and the precipitation.

A surface trough located over the NW Bahamas will move into the
eastern Gulf of Mexico by Thu morning. Fresh to strong NE winds
are expected west of the trough axis, including the Florida
Straits, through tonight. Otherwise, high pressure located just N
of the forecast region will dominate the SW N Atlantic through
Mon. Fresh to locally strong winds are expected to pulse N of
Hispaniola during the evening hours through Sat night.

$$
mt/gr/pp/jb
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