[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040510
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
110 AM EDT Wed Jul 4 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 vigorous tropical wave is producing a concentrated area of
showers and thunderstorms several hundred miles southwest of the
Cabo Verde Islands. As of 0000 UTC, this tropical wave is
relocated farther E, and now extends from 16N31W to 04N32W. A 1010
mb low pressure has developed along the wave's axis near 09N32W.
Although satellite images show some signs of organization, the
disturbance is moving west-northwestward toward an area unfavorable
for tropical cyclone formation. Currently, the Tropical Weather
Outlook gives this system a low change of development through 48
hours.

A tropical wave has entered the Caribbean Sea. Its axis is along
62W, and is generating scattered showers and isolated tstms over
the Windward Islands as well as over the eastern Caribbean mainly
S of 15N E of 65W. A recent scatterometer pass clearly indicates
the wind shift associated with the wave axis, with fresh to
locally strong SE winds just E of the Windward Islands. Gusty
winds to near 35 kt have been reported in the Windward Islands
with the wave passage. Moisture associated with this wave will
remain S of Puerto Rico and the VIrgin Islands. The wave will
reach the central Caribbean late Wed into Thu, and the western
Caribbean by Fri.

Another tropical wave is over the western Caribbean, and has an
axis extending along 82W. A large area of moderate to isolated
strong convection is at the base of the wave and covers the waters
from 12N-15N between 80W and the coast of Nicaragua. Abundant
moisture associated with this wave will spread over parts of
Nicaragua and Honduras, including also the Gulf of Honduras today,
bringing scattered showers and tstms. The wave is forecast to move
west of the area by Thu.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from the coast of
of Guinea-Bissau near 12N16W, then continues westward to a 1010 mb
low pressure located near 09N32W to 05N40W. The ITCZ stretches
from 05N40W to the coast of Guyana near 06N58W. Aside from the
convection associated with the tropical waves, scattered moderate
to isolated strong convection is seen from 01N-05N between 30W-
37W. Scattered moderate is from 06N-08N between 35W-42W.

...DISCUSSION...

GULF OF MEXICO...

A trough extends from a 1014 mb low centered in southern Louisiana
near 30N92W to 28N89W to 25N90W. Widespread showers with embedded
tstms are noted N of 26N and W of the trough to about 94W. Lightning
density indicates frequent lightning with much of the observed
convection, more concentrated now over the upper Texas coast.
This convective low pressure system will continue to enhance
showers and thunderstorms system across the northern Gulf states
from southern Mississippi to SE Texas today.

The remainder of the Gulf remains under the influence of a weak
ridge extending W from the Atlantic. This system is producing
mainly light to gentle anticyclonic flow and seas of 1-3 ft across
much of the Gulf region. This pattern will change little over the
next 48 hours. A surface trough will emerge off the Yucatan
Peninsula each evening through Sat, enhancing nocturnal winds over
the SW Gulf.

CARIBBEAN SEA...

Two tropical waves are moving across the Caribbean Sea. Please
see the Tropical Waves section for details. A recent ASCAT pass
provides observations of fresh to strong winds across the central
Caribbean between 70W-75W. Fresh winds are noted over the eastern
Caribbean, and gentle to moderate winds over the NW Caribbean,
including the Yucatan Channel. Fresh to strong trades are expected
across much of the area S of 18N and E of 83W through at least
Fri. Winds will approach gale force near the coast of Colombia
Thu night through Fri night.

ATLANTIC OCEAN...

As of 0300 UTC, a surface trough, reflection of an upper level
cyclonic circulation, extends from 32N78W to 24N79W. Scattered
showers and isolated tstms are observed ahead of the trough axis
forecast to move west into Florida through tonight.

An area of cloudiness and showers remains a few hundred miles
southeast of Bermuda. Although this disturbance is currently
disorganized, environmental conditions could become more conducive
for a low pressure system to form by late this week in the area
southwest of Bermuda. The system is then forecast to move generally
northward over the weekend and begin interacting with a frontal
system on Sunday, which would limit any additional development.

Surface high pressure of 1032 mb located W of the Azores near
37N39W extends a ridge across the remainder of the central and
eastern Atlantic forecast waters. Moderate to fresh trade winds
are noted along the southern periphery of the ridge, which
reaches the NE Caribbean.

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

$$
GR
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