[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161728
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
128 PM EDT Sat Jun 16 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...TROPICAL WAVES...

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

A tropical wave is added to the 1200 UTC analysis/surface map
along 18W/19W based on the Hovmoller Diagram that shows the
westward propagation of the wave. This system is also well
defined on the TPW product, and model diagnostics guidance.
Scattered moderate to isolated strong convection is near the
southern end of the wave's axis from 5N-9N between 16W-19W.

A tropical wave is in the E Atlantic, with axis extending from
13N33W to 04N34W, moving W at 10 kt. A modest surge of moistened
air is noted in association with the wave in TPW imagery.
Scattered showers are where the wave meets the ITCZ axis.

A tropical wave is in the central Atlantic, with axis extending
from 15N47W to 04N48W, 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 isolated showers are observed
near the wave's axis. This wave will move across the waters E of
the Lesser Antilles Sun night through Mon night, and the eastern
Caribbean Tue through Wed night.

A tropical wave is moving westward across the eastern Caribbean.
Its axis extends along 66W/67W. African dust surrounds the wave.
As a result, shallow moisture with embedded showers is associated
with the wave. This wave will move across the remainder of the
eastern Caribbean through Sun, the central Caribbean Sun night
through Tue and the western Caribbean Tue night through Wed night.

A tropical wave is moving across Central America, with axis along
87W/88W from 11N-20N, moving W at 10 kt. Scattered moderate to
isolated strong convection is near the southern end of the wave's
axis affecting parts of Nicaragua, Honduras, and El Salvador. The
GFS model indicates plenty of moisture over Central America and
the Yucatan Peninsula this weekend.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 11N15W
to 07N30W. The ITCZ continues from 07N30W to 08N34W to 06N42W to
the coast of Guyana near 7N59W. Besides the convection mentioned
in the Tropical Waves section, isolated moderate convection is
within about 90 nm on either side of the monsoon trough between
22W-25W.

...DISCUSSION...

GULF OF MEXICO...

A strong surface trough extends from 23N91W to the eastern Bay of
Campeche. Fresh to locally strong winds are near the trough axis.
A large cluster of moderate to strong convection follows the
trough covering the far NW Caribbean, the Yucatan Channel, the NE
portion of the Yucatan Peninsula and the Gulf waters S of 24N
between 85W-90W. 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 central Gulf of Mexico later today and will reach
portions of the Texas and southwestern Louisiana coasts on Sunday.
The trough is interacting with an upper-level low located over the
western Gulf. Scattered moderate convection is noted near the
northern end of the trough while scattered showers and isolated
tstms are seen over the SW Gulf in association with the upper
level-low. The remainder of the Gulf is under the influence of a
ridge.

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

CARIBBEAN SEA...

As previously mentioned, a cluster of moderate to strong convection
covers the far NW Caribbean, including the Yucatan Channel, mainly
N of 19N W of 85W. A line of tstms has persisted this morning
along the E coast of the Yucatan Peninsula. Cancun and Cozumel
have been reporting rain for several hours. This convective
activity is the result of a trough interacting with an upper-
level low over the Gulf of Mexico.

Strong trades across the central Caribbean between 69W and 83W
will slowly diminish through Sun night. 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
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 Tue and Wed.

ATLANTIC OCEAN...

As of 1500 UTC, a cold front enters the forecast waters and
extends from 31N68W to 30N73W to 31N77W. A surface trough remains
offshore northern and central Florida and stretches from 30N77W to
the NW Bahamas. Scattered showers and tstms are roughly affecting
the waters N of 28N between 65W-77W. Another surface trough is
analyzed ahead of the front from 30N64W to 26N72W. 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 and central Florida will be overtaken
by the cold front later today. The front cold front will drop
southward through early next week, reaching from 31N60W to 28N65W
to 27N70W by early Sun morning. 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

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net