[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011205
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 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 21W 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. Isolated moderate convection is
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 31N86W to 27N89W. Abundant
cloudiness and scattered showers and thunderstorms are associated
with the low/trough affecting mainly the waters N of 27N and E of
89W. The low and trough will drift northwestward through tonight
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 28N90W. 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 tonight.
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. Overnight
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 generally along the
north coast of Panama. An upper- level low, currently over Cuba,
will drift westward into the NW Caribbean through Mon, and will
enhance convection across the extreme western Caribbean and over land
areas across the NW Caribbean.

ATLANTIC OCEAN...

Three tropical waves are moving across the waters between the
coast of West Africa and the Lesser Antilles. Refer to the
Tropical Waves section above for details. A surface trough is
over the central Atlantic and extends from 32N51W to 27N52W. Light
winds are on either side of the trough axis based on earlier
scatterometer data. This trough is a surface reflection of an
upper-level low spinning near 29N50W. Scattered showers and
thunderstorms are associated with this trough from 26N to 32N
between 47W and 53W.

Surface high pressure located NW of the Azores is in control of
much of the remainder of the forecast area, with a ridge
extending 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 has developed over this region NE of
the Bahamas and extends from 32N62W to 26N65W. Scattered showers
and thunderstorms are along and within 300 nm NE of the trough
axis. This trough will 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 shows an extensive area of African dust that
extends from the west coast of Africa to the eastern Caribbean
this morning. 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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