[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010523
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
123 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...TROPICAL WAVES...

A tropical wave that has emerged off the west coast of Africa
extends its axis along 18W from 04N-14N. Scattered to numerous moderate
convection is noted on either side of the wave's axis from 08N-
14N and E of 20W to the coast of Africa. A moisture surge in the
TPW product is observed with this wave.

A tropical wave has an axis extending along 37W from 03N-18N,
moving W at 10-15 kt. This wave was slightly repositioned based on
visible satellite imagery, model diagnostics and TPW imagery.
Scattered showers are present where the wave meets the ITCZ near
06N. This wave is surrounded by dry Saharan air which is inhibiting
strong convection.

A tropical wave has an axis extending along 54W from 04N-19N,
moving westward at around 10-15 knots. Scattered showers are
present where the wave meets the ITCZ near 08N. The wave shows up
well in model diagnostics guidance and TPW product. African dust
surrounds this wave also. A patch of moisture with embedded
showers is noted ahead of the wave approaching the Windward
Islands. Tropical moisture associated with this feature will reach
the waters E of the Windward Islands through the morning hours,
and move across the islands today, increasing the likelihood of
showers and isolated tstms.

A tropical wave has an axis extending N from northeast Colombia
to the Windward Passage. 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 over the Yucatan
Peninsula into the eastern Pacific region. This wave is slowing
down and moving W at only around 5 kt. TPW satellite imagery and
model diagnostics show this wave to be poorly defined.

...MONSOON TROUGH/ITCZ...

The monsoon trough develops over the Atlantic Ocean near 10N19W
and continues to 06N36W. The ITCZ stretches from 06N39W to
06N52W. Aside from the convection associated with the tropical
waves, scattered moderate convection is observed within about 150
nm on either side of the monsoon trough between 20W-26W. Scattered
showers are noted along the ITCZ.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends over the northeastern Gulf from a 1014 mb
low 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

$$

ERA
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