[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250006
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Tue Jul 24 2018

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2145 UTC.

...TROPICAL WAVES...

A tropical wave is over the far eastern Atlantic just to the west
of the Cape Verde Islands with its axis along 25W extending from
06N-21N, moving westward at 15 kt. A large area of Saharan dust
is noted along the wave mainly north of 14N. The dust is limiting
convective activity from developing along and near the wave. Only
isolated showers are possible within 60-90 nm of the wave axis.

A tropical wave is over the eastern Atlantic with its axis
extending from 05N39W to 18N39W, moving westward at 15 kt. A
large area of Saharan Air layer (SAL) dust is noted along the
wave mainly north of 10N. Like the wave along 25W, the SAL
is inhibiting deep convective activity from developing along or
near this wave. Only isolated showers and weak isolated
thunderstorms are seen within 60 nm either side of the wave
axis from 05N-10N.

A tropical wave is over the central Atlantic with its along
57W from 06N-18N, moving westward at 15 kt. This wave is on the
leading edge of a large area of Saharan Air Layer (SAl). As a
result, the surrounding environment is very dry and stable and
no shower or thunderstorm activity is seen in satellite imagery.

A tropical wave is over the eastern Caribbean with its axis
extending from the central Dominican Republic southward along
71W/72W to inland Venezuela 12N72W, moving westward at 15-20 kt.
This wave is followed by a batch of low-level moisture as observed
in the latest Total Precipitable Water (TPW) animation. The wave
is also to the east of an upper-level low located over Haiti,
with a trough extending southwestward to near 13N75W. This is
helping to provide enough lift to the present low-level moisture
to develop scattered showers and isolate thunderstorms from 13N
18N between the wave and 66W.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Africa near
15N17W to 10N30W and ends just to the east of the tropical
wave at 39W. The ITCZ extends from 08N41W to the coast of South
America near 05N53W. Besides the convection mentioned in the
tropical wave section, scattered moderate convection is seen
within 60 nm north of the axis between 34W-37W.

...DISCUSSION...

GULF OF MEXICO...

A 1011 mb low is centered over the Florida/Georgia border at
30N84W. A stationary front extends southwestward from the low to
the NE Gulf of Mexico near 28N87W then west-northwestward to
northeastern Texas. A deep layer trough extends from northern
Georgia to the eastern gulf waters as seen in water vapor imagery.
low . This feature is sustaining scattered showers and thunderstorms
that earlier formed near the stationary front. This activity is
moving eastward over the waters from 24N-27N between 87W-92W. This
activity may weaken some more tonight. Additional activity is
expected to re- develop late tonight into early on Wed over or
near the same general area, with more coverage over the far
eastern gulf waters. The remainder of the basin is under the
influence of a broad surface ridge, anchored by a weak high
centered near the Yucatan Channel at 20N85W, maintaining fair
weather and light to gentle winds. 1-3 ft seas are south of the
front, with little change expected through Fri.

The aforementioned stationary front will gradually weaken to a
trough by Thu. Elsewhere, a surface trough will move off the
Yucatan Peninsula into the Bay of Campeche each evening,
accompanied by fresh nocturnal winds.

CARIBBEAN SEA...

A tropical wave is in the eastern Caribbean. See above. Scattered
moderate isolated strong convection is over western Panama.
Relatively dry and stable conditions persist elsewhere. Fresh to
strong winds will prevail in the south-central Caribbean, while
gentle to moderate winds are expected elsewhere the next several
days, with the exception of light to gentle winds over the western
Caribbean.

ATLANTIC OCEAN...

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

Scattered moderate isolated strong convection is north of the
Bahamas and W of 72W related to diffluent flow aloft. Gusty winds
are possible near the thunderstorms. Moderate south to southwest
winds are noted west of 70W with 4-6 ft seas in open waters.
Scattered moderate convection is over the central Atlantic from
26N-30N between 54W-62W. This convection is also due to another
diffluent flow aloft. A strong ridge prevails across the rest of
the basin, anchored by a 1033 high centered near 38N53W. This
subtropical high along with low pressure over the southeast U.S.
will produce moderate to fresh southerly winds across the waters
north of 25N and west of 70W including Florida coastal waters
through Wed. Moderate to fresh winds are also expected south of
22N, including approaches to the Windward Passage. Ridging will
dominate the area through the end of the week.

For additional information
please visit http://www.hurricanes.gov/marine

$$
Formosa/Aguirre
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