[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251717
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
117 PM EDT Wed Jul 25 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...TROPICAL WAVES...

A tropical wave is over the far eastern Atlantic west of the Cape
Verde Islands with axis along 34W extending from 05N-19N, moving
westward at 15-20 kt. A large area of Saharan dry air and dust is
hindering convective activity from developing at the time.

A tropical wave is over the central Atlantic with axis along 46W
from 04N-15N, moving westward at 15-20 kt. A large area of
Saharan dry air and dust is hindering convective activity from
developing at the time.

A tropical wave is over the eastern Caribbean with axis along 62W
from 08N- 19N, moving westward at 15 kt. A large area of Saharan
dry air and dust is hindering convective activity from developing
at the time.

A tropical wave is over the western Caribbean with axis along 81W
from central Cuba to central Panama, moving westward at 15-20 kt.
Shallow moisture in the northern wave environment along with a
region of middle to upper level diffluence east of the wave is
supporting isolated moderate convection off the coasts of E Cuba
and Jamaica. In addition, scattered moderate convection is over
the southern portion of the wave along the coasts of Panama and
Costa Rica S of 11N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Africa near
11N15W to 09N20W to 10N34W to 08N37W. The ITCZ extends from
08N37W to 08N45W. The ITCZ resumes W of a tropical wave near
08N48W and continues to the coast of South America near 07N58W.
Scattered moderate convection is along the coast of W Africa from
07N-12N between 13W-21W.

...DISCUSSION...

GULF OF MEXICO...

An upper level trough is over the NE Gulf of Mexico and N Florida.
This feature supports a 1013 mb surface low near 30N86W. Diffluence
aloft east of the upper level trough is sustaining convection
over the W Atlantic off the Florida coast, while diffluence to the
south is producing convection over the south central Gulf of
Mexico. Convection is expected to continue over these areas
through Thu. The Atlantic subtropical ridge will then extend an
axis SW across the eastern Gulf. Surface ridging is forecast to
continue through the weekend, thus providing light to gentle
variable flow across the basin. Elsewhere, a surface trough will
move off the Yucatan Peninsula into the Bay of Campeche each
evening, accompanied by fresh nocturnal winds. Scattered to
isolated showers are possible in the Bay of Campeche with the
surface trough.

CARIBBEAN SEA...

Two tropical waves are over the Caribbean. See above. Scattered
moderate convection is over N Colombia, Panama, and Costa Rica.
Isolated showers are located over waters S of Puerto Rico and
Hispaniola between 65W and 75W. These showers are being sustained
by a small region of shallow moisture and diffluence aloft.
Relatively dry and stable conditions persist elsewhere. Expect
the surface pressure gradient to support fresh to strong winds in
the south-central basin through Fri. Elsewhere, stable conditions
with light to moderate winds are expected.

ATLANTIC OCEAN...

Two more tropical waves are moving across the basin lacking
convection due to the presence of the dry air in the Saharan Air
Layer. Refer to the tropical waves section above for more details.
Scattered moderate convection is across the W Atlantic including
the northern Bahamas, W of 75W. Farther east, a middle to upper
level low supports an area of scattered moderate convection from
22N-28N between 56W-64W. Otherwise, the Atlantic subtropical ridge
dominates the remainder basin being anchored by a 1031 mb high
centered near 37N55W.

Expect convection north of the Bahamas through the weekend.
Thesurface pressure gradient between the Atlantic 1031 mb
subtropical high and the 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
today. Moderate to fresh winds are also expected south of 22N,
including approaches to the Windward Passage. Surface ridging
will dominate the central and eastern Atlantic through the end of
the week providing stable and dry conditions.

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

$$
Formosa
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