[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170546
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
146 AM EDT Sun Jun 17 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
0530 UTC.

...TROPICAL WAVES...

Three tropical waves are noted between the W coast of Africa and
the Lesser Antilles.

A tropical wave extends its axis along 20W between 04N-13N. This
system is well defined in the TPW product and model diagnostics
guidance. Scattered moderate convection is from 06N-11N between
18W-25W.

A tropical wave is in the E Atlantic, with axis extending from
12N37W to 02N39W, moving W at 10-15 kt. A modest surge of
moistened air is noted in association with the wave in TPW
imagery. Scattered showers are noted along the wave axis and
vicinity between 36W-42W.

A tropical wave is in the central Atlantic, with axis extending
from 15N50W to 05N51W, moving W at 10 kt. The wave coincides with
a high amplitude bulge of moisture as depicted in the TPW
product. Currently, shallow moisture and scattered showers are
observed near the wave's axis from 08N-12N.

A tropical wave is moving westward across the eastern Caribbean.
Its axis extends along 68W. African dust surrounds the wave. As a
result, shallow moisture with embedded showers are noted with
this wave.

A tropical wave is moving across the southern Yucatan Peninsula,
with axis along 91W from 11N-19N, moving W at 10 kt. Scattered to
numerous moderate convection prevails in the wave's environment
affecting the area between 88W-93W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 10N14W
to 08N31W. The ITCZ is analyzed from 04N41W to 05N50W, then
resumes near 07N53W to 07N58W. Besides the convection mentioned
in the Tropical Waves section, scattered showers are within 90
nm on either side of both boundaries between 35W-50W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends across the western Gulf from 25N93W to
19N95W. Fresh to locally strong winds are near the trough axis
prevailing mostly across the central Gulf waters between 88W-94W.
Scattered moderate convection is noted between 86W-93W. This
activity is supported by an upper-level low, currently centered
near 15N95W. Scattered to numerous convection follows the trough
covering the far NW Caribbean, the Yucatan Channel, and the
Yucatan Peninsula. Although environmental conditions are not
expected to be favorable for significant tropical cyclone
development, heavy rains and gusty winds are likely to spread
across the Gulf waters overnight, and will reach portions of the
Texas and southwestern Louisiana coasts later today. The
remainder of the Gulf is under the influence of a ridge.

The surface trough will move WNW through Sun night accompanied by
numerous showers and thunderstorms that could produce rough seas.
A tightening of the pressure gradient between the trough and high
pressure that extends westward from the Atlantic will continue to
support fresh to strong SE winds over the west-central Gulf waters.
These winds will spread westward through Tue while gradually
diminishing with the trough shifting inland over Texas.

CARIBBEAN SEA...

As previously mentioned, an area of moderate convection covers
the far west Caribbean, including the Yucatan Channel, mainly
west of 82W. This convective activity is the result of a trough
interacting with an upper-level low centered over the Gulf of
Mexico.

Strong trades across the central Caribbean between 69W and 83W
will slowly diminish tonight. The strongest winds will become
confined to the S central waters, with similar pulsing winds
continuing in the vicinity of the Gulf of Honduras.

Two tropical waves are noted across the basin. Please, see the
Tropical Wave section for details. A tropical wave is forecast to
reach the waters E of the Lesser Antilles Sun night through Mon
night, and the eastern Caribbean Tue through Wed night. It is
expected to be accompanied by scattered showers and thunderstorms.
As the wave moves across the Lesser Antilles into the eastern
Caribbean, the moisture field is forecast by the GFS computer
model to expand over the Leeward Islands, the UK/US Virgin Islands
and Puerto Rico, bringing an increase in showers and tstms with
likely gusty winds by mid week.

ATLANTIC OCEAN...

A cold front enters the forecast waters and extends from 31N64W
to 29N70W to 31N78W. Scattered moderate convection is noted along
and south of the front between 58W-68W. A surface trough remains
near the northern Bahamas from 29N76W to 26N77W with no convection.
High pressure of 1032 mb located just over the Azores extends a
ridge across the forecast area. Three tropical waves are moving
westward across the southern periphery of the ridge.

The trough offshore northern Bahamas will be overtaken by the
cold front towards the morning hours. The cold front will continue
moving southeast through early next week. The high pressure ridge
south of the boundaries will shift southward across the western
Atlantic.

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

$$

ERA
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