[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232339
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Tue Aug 24 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave extends its axis along 23W from 19N
southward and moving W at 10 to 15 kt. Scattered moderate
convection is noted from 02N to 10N between 22W and 28W. Some
slow tropical development will be possible over the next several
days while the disturbance moves westward to west-northwestward
over the eastern tropical Atlantic.

A well defined Atlantic tropical wave is near 40W from 20N
southward and moving W at 10 to 15 kt. Scattered showers are
noted from 07N-21N between 34W and 44W. Little tropical
development is expected during the next couple of days due to
only marginally conducive ocean temperatures. Thereafter,
however, some gradual development will be possible through the
end of the week while the system over the central Atlantic.

A weak Atlantic tropical wave is along 54W from 18N southward
and moving W near 15 kt. Much drier air at mid and upper levels
is hindering any significant convection near this wave.

A robust Caribbean tropical wave is near 66W from 20N southward
across the Virgin Islands to E Venezuela, and moving W near 10
kt. Enhanced by strong trade-wind convergence in the vicinity,
scattered showers and isolated thunderstorms are occurring across
the S central and SE Caribbean Basin, and farther E into the
Atlantic from 9N to 14N between 55W and the Windward Islands. A
broad low is expected to form with this wave over the
southwestern Caribbean by late week. Thereafter, environmental
conditions are forecast to become favorable for gradual
development while the system moves over the northwestern
Caribbean.

Another Caribbean tropical wave is along 84W from 20N southward
into the E Pacific, moving W at 10 to 15 kt. Scattered moderate
convection prevails over land south of 16N between 82W and 87W.

A tropical wave is over the E Bay of Campeche near 92W from 21N
southward across S Mexico and Guatemala into the E Pacific, and
moving W near 15 kt. Scattered moderate to strong convection
prevails south of 22N between 89W and 95W.

...MONSOON TROUGH/ITCZ...

A monsoon trough extends from the African coast near 15N17W
through a 1011 mb low pressure near 13N42W to 13N44W. Aside from
the convection described in the tropical waves section above, no
other convection is noted at this time.

...GULF OF MEXICO...

A surface ridge prevails across the basin anchored over the
western Atlantic. Convergent surface winds N of the ridge axis
are coupling with modest divergence aloft to trigger scattered
showers and isolated thunderstorms from near New Orleans eastward
including the Florida peninsula. An upper-level low over E
central Mexico coupled with the northern extension of a tropical
wave is enhancing similar conditions over the SW Gulf, including
the W Bay of Campeche. Moderate to locally fresh winds and seas
up to 4 ft are expected near strong thunderstorms. Otherwise,
light to Gentle E to ESE winds associated with the ridge and seas
at 1 to 3 ft prevail across much of the Gulf.

For the forecast, high pressure will dominate the basin through
Fri producing mainly gentle to moderate E to SE winds. Fresh
winds will likely pulse west of the Yucatan Peninsula tonight and
again Tue night.

...CARIBBEAN SEA...

Refer to the section above for details on the tropical waves
moving across the basin.

Convergent trade winds are causing scattered showers and isolated
thunderstorms over the W central basin, N of Panama and Colombia.
The latest satellite scatterometer and altimeter data reveal
fresh to strong NE to E trade winds and seas at 5 to 8 ft across
the central and E basin. Gentle to moderate trades and seas of 2
to 4 ft prevail for the rest of the basin.

For the forecast, fresh to strong trade winds will dominate most of
east and central Caribbean through midweek building seas to 8 to
10 ft. Fresh to locally strong winds are also expected in the
Windward passage through Tue night. A tropical wave currently
over the eastern Caribbean seas is likely to form a broad low
pressure in the SW Caribbean Sea late this week.

...ATLANTIC OCEAN...

Refer to the section above for details on the tropical waves
moving across the basin.

Enhanced by an upper-level trough along the US E Seaboard near
34N74W, convergent SE winds are creating scattered showers off
the Georgia-N Florida coast, N of 28N and W of 74W. The
Atlantic ridge curves westward from the 1023 mb Azores high near
34N24W to the Bermuda high near 32N63W. These features continue
to provide gentle to moderate winds and seas of 3 to 5 ft N of
23N between 23W and the Georgia-Florida coast. Moderate to fresh
with locally strong trade winds and seas at 7 to 9 ft are found
near the Canary Islands N of 16N between the NW African coast and
23W, and W of the Cape Verde Islands from 08N to 22N between 34W
and 40W. Moderate to fresh trades and seas of 5 to 6 ft are
found from 10N to 23N between 50W and the Lesser Antilles. Gentle
to moderate SE to S winds and seas at 5 to 7 ft prevail for the
rest of the Atlantic Basin.

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 Thu, possibly reaching
the NE waters 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.

$$
ERA
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