[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301037
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
637 AM EDT Sat Jun 30 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...

A tropical wave has an axis extending from 04N26W to just SW of the
Cabo Verde Islands near 16N26W moving W around 10 kt. This wave
is well defined in model diagnostics guidance and TPW animation.
Scattered moderate convection is limited to a small area near the
axis of this wave from 04N to 06N between 21W and 24W as it is
nearly surrounded by dry Saharan air.

A tropical wave has an axis extending N from 05N50W to 17N49W and
is moving westward around 15 knots. Scattered moderate convection
is present from 03N to 07N between 44W and 51W on the SE side of
the wave. The wave shows up well in model diagnostics guidance and
TPW product and has dry Saharan air on its N side. Tropical
moisture associated with this wave will reach the waters E of the
Windward Islands tonight, and move across the islands on Sat,
increasing the likelihood of showers and tstms.

A tropical wave has an axis extending N from NW Venezuela to the
eastern Dominican Republic near 19N69W. This feature is moving W
between 10 and 15 kt and despite its longitude has dry Saharan air
on both sides. As a result, there is no significant convection
currently associated with this wave. Some moisture on the SE side
of this wave could enhance convection over the basin this weekend
before the wave exits the basin Sun night.

Another tropical wave has an axis extending N from the eastern
Pacific near 07N88W to northern Belize near 18N88W. 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 enters the Atlantic Ocean from the coast of
Mauritania near 17N16W and continues to 07N27W to 06N35W. The
ITCZ continues from 06N35W to 03N44W to 05N49W. Aside from the
convection associated with the tropical waves, scattered moderate
and isolated strong convection is observed from 05N to 10N
between 12W and 17W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough curves SW from the Florida Big Bend near 30N84W over
the NE Gulf to near 24N86W. Scattered showers are occurring along
and up to 60 nm E of the trough axis.

The remainder of the Gulf is under the influence of a weak high
pressure center of 1017 mb located over the central Gulf near
27N90W. This system is producing light to gentle winds and seas
of 2-3 ft over the eastern half of the Gulf, and gentle to
moderate 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.

The western Atlantic high pressure is forecast to weaken on Sat
and remain stretched across Florida and the eastern Gulf. A
surface trough will emerge off the Yucatan Peninsula each night,
enhancing nocturnal winds in the SW Gulf through early next week.

CARIBBEAN SEA...

A pair of tropical waves are moving across the basin. Please, see
the Tropical Waves section for details. Recent scatterometer data
depicted fresh to strong winds across the south-central Caribbean,
while moderate to fresh trades across the remainder of the basin
S of 12N between 72W-77W. Light to gentle winds are noted over
the NW Caribbean. Winds and seas in the central Caribbean will
gradually diminish through early next week as high pressure N of
area weakens.

Scattered moderate convection is seen over the SW Caribbean,
mainly S of 12N between 80W-84W. Similar convection is over the
eastern Caribbean due to the presence of a tropical wave. Isolated
to scattered showers and tstms are over parts of Hispaniola, the
Windward Passage, Jamaica and the Cayman Islands. An upper-level
low centered over the Windward Passage is helping to induce this
convective activity. The upper-level low will drift westward into
the NW Caribbean over the weekend, and will continue to enhance
convection across the area.

ATLANTIC OCEAN...

Two 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 36N48W to 28N50W. Light winds are on
either side of the trough's axis based on scatterometer data. This
trough is a surface reflection of an upper-level low spinning
near 31N49W.

A 1035 mb surface high located NW of the Azores near 44N40W is in
control of the remainder of the area, extending a ridge SW across
the west-central Atlantic. Moderate to fresh winds are around the
southern periphery of the ridge W of 48W to the Lesser Antilles.
The ridge will slowly weaken through early next week. Generally
benign marine conditions are expected across the region through
this period.

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

$$
GR
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