[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011032
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
632 AM EDT Sun Jul 1 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 0600 UTC surface analysis and satellite imagery through
1100 UTC.

...TROPICAL WAVES...

The tropical wave that most recently emerged off the west coast
of Africa has an axis extending from 03N20W to 15N20W and is
heading W around 20 kt. Scattered to numerous moderate and
isolated strong convection is noted on either side of the wave
axis from 05N to 12N eastward from 24W to beyond the coast of
Africa. A moisture surge in the TPW product coincides with this
wave.

A tropical wave has an axis extending from 03N39W to 17N39W. This
wave is quickly moving W around 30 kt. This wave is well defined
in model diagnostics as well as TPW satellite imagery. Scattered
moderate convection is present within 90 nm of where the wave
meets the ITCZ near 06N. This wave is surrounded by dry Saharan
air which is inhibiting deep convection.

A tropical wave has an axis extending from 04N56W to 19N55W,
moving westward around 15 knots. Scattered moderate convection is
seen where the wave meets the ITCZ from 06N to 08N between 53W and
58W. The wave shows up well in model diagnostics guidance and the
TPW product. African dust surrounds this wave also. Tropical
moisture associated with this feature will reach the Windward
Islands by this afternoon and produce a modest increase in the
likelihood of showers and isolated tstms for the eastern
Caribbean.

A tropical wave has an axis extending N from northeast Colombia
near 08N76W to just SW of the eastern tip of Cuba. This wave is
moving W between 10 and 15 kt and has dry Saharan dust in its
environment. As a result, there is no significant convection
currently associated with it. The wave will reach Central America
by Sun night.

Another tropical wave has an axis extending N from 11N94W over
the Isthmus of Tehuantepec into the Bay of Campeche near 20N92W.
This wave is slowing down and moving W around 10 kt. TPW satellite
imagery and model diagnostics show this wave to be poorly
defined. No significant convection is currently associated with
this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from the coast of
Mauritania near 17N16W to 17N17W, then resumes near 09N22W to
06N36W. The ITCZ stretches from 06N42W to 07N48W to 06N54W. Aside
from the convection associated with the tropical waves, scattered
moderate convection is observed from 05N to 07N between 24W and
29W and from 06N to 08N between 47W and 53W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends over the northeastern Gulf from a 1014 mb
low over the Florida Panhandle near 31N85W to 28N86W. Abundant
cloudiness and scattered showers are associated with the
low/trough affecting mainly the waters N of 28N and E of 87W. The
low and trough will move little tonight, then they will drift
northwestward through the day while weakening. Scattered showers
and thunderstorms will continue over much of the NE/north-central
Gulf waters through at least Mon.

The remainder of the basin is under the influence of a weak high
pressure center of 1016 mb located over the north-central Gulf
near 27N90W. This system is producing light to gentle
anticyclonic flow and seas of 2-3 ft over the eastern half of the
Gulf, and gentle to moderate Se to S winds and seas of 3-5 ft over
the western half of the Gulf. Moderate to fresh return flow is
expected over the west-central and NW Gulf through the weekend.
This weak high pressure will change little through mid-week. A
surface trough will emerge off the Yucatan Peninsula each evening
through Wed, enhancing nocturnal winds over the SW Gulf through
this period.

CARIBBEAN SEA...

A tropical wave is moving across the central Caribbean. Please,
see the Tropical Waves section for details. Recent scatterometer
data depicted fresh to strong winds across the south-central
Caribbean south of 14N between 72W-78W, while moderate to fresh
trades prevail across the remainder of the basin S of 18N and E
of 80W. Light to gentle winds are noted over the NW Caribbean. A
surface ridge will remain north and northeast of the Caribbean
and Tropical N Atlantic waters through the next few days. Fresh
to strong winds across the south-central Caribbean will gradually
diminish through Tue before strengthening again on Wed.

Convection continues to flare up over the SW Caribbean mainly in
the vicinity of the monsoon trough, which is along Central
America at this time. The upper-level low, currently over Cuba,
will drift westward into the NW Caribbean over the weekend, and
will continue to enhance convection across the basin.

ATLANTIC OCEAN...

Three tropical waves are moving across the waters between the
coast of West Africa and the Lesser Antilles. Refer to the
Tropical Wave section above for details. A surface trough is over
the central Atlantic and extends from 32N48W to 29N51W. Light
winds are on either side of the trough axis based on scatterometer
data. This trough is a surface reflection of an upper-level low
spinning near 30N50W. Scattered showers are associated with this
trough.

A 1033 mb surface high located NW of the Azores near 45N36W is in
control of the remainder of the forecast area, extending a ridge
SW across the west-central Atlantic. Moderate to fresh winds are
around the southern periphery of the ridge W of 50W to the Lesser
Antilles. The ridge will weaken through Tue in response to the
development of broad low pressure system NE of the Bahamas. A
surface trough will develop from the low pressure and move
westward across the NW Bahamas Tue, and inland Florida Wed.
Scattered showers and thunderstorms are expected with the trough.
Otherwise, generally tranquil marine conditions are expected
across the region through the middle of next week.

GOES-16 RGB Geocolor showed an extensive area of African dust
that extends from the west coast of Africa to the eastern
Caribbean this afternoon. The Saharan dust occasionally obscures
sky conditions near the Caribbean islands. The dust turns skies
hazy, reducing visibility and can result in poor air quality.

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

$$
CAM/ASL
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