[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291732
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
132 PM EDT Fri Jun 29 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...

A tropical wave extends from the Cabo Verde Islands near 16N23W to
04N23W moving W at 20 kt. This wave is noted in model diagnostics
guidance and TPW animation. Convection is limited near the wave's
axis.

A tropical wave extends from 18N43W to 04N45W, moving westward 15
to 20 knots. Scattered moderate convection is near the southern
end of the wave's axis. The wave shows up well in model diagnostics
guidance and TPW product. Tropical moisture associated with this
wave will reach the waters E of the Windward Islands tonight, and
move across these islands on Sat, increasing the likelihood of
showers and isolated tstms. The wave will enter the eastern
Caribbean early on Sun.

A tropical wave is moving across the eastern Caribbean and
extends from the Virgin Islands to central Venezuela. Scattered
moderate convection is noted just ahead the wave's axis from 12N-
16N between 66W-69W. A high amplitude N bulge of moisture is
associated with this wave based on the TPW product. However, the
GFS computer model indicates that most of the moisture field related
to this wave will remain S of the Greater Antilles during the
upcoming weekend, with only a slightly increase in tropical moisture
across islands. This wave will move across the Caribbean basin
through Sat night.

Another tropical wave extends across the NW Caribbean and Central
America into the EPAC region. Its axis is along 86W. Scattered
moderate convection is where the wave meets the monsoon trough in
the EPAC region.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean through the coast of
Guinea near 10.5N14W and continues to 06N30W. The ITCZ begins
near 06N30W and continues to 05N40W to the coast of South America
near 05N52W. Aside from the convection related to the tropical
waves, scattered moderate convection is from 04N-07N between 25W-
31W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends across northern Florida into the NE Gulf.
Scattered showers and tstms have flared up near the trough's
axis, affecting roughly the waters NE of line from Tampa Bay to
SE Louisiana. Doppler Radar from the SE U.S. also indicates
scattered showers and tstms over the west coast of Florida and
regional waters. This convective activity could produce locally
gusty winds, briefly choppy seas and dangerous lightning.

The remainder of the Gulf is under the influence of a weak high
pressure center of 1019 mb located over the eastern Gulf near
25N88W. 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 Tue.

CARIBBEAN SEA...

A pair of tropical waves are moving across the basin. Please, see
Tropical Waves section for details. Recent scatterometer data
provide observations of fresh to strong winds across the south-
central Caribbean, and moderate to fresh trades across the
remainder of the basin S of 18N E of 80W. Mainly gentle winds are
noted over the NW Caribbean. Winds and seas in the central Caribbean
will gradually diminish Sun through Tue as high pressure N of area
weakens.

Scattered moderate convection is seen over the SW Caribbean,
mainly S of 11N between 77W-83W. 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 32N47W to 27N49W. 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 32N51W. Farther east, a cold front enters the forecast area
near 31N12W and crosses just N of the Canary Islands to near
28.5N20W. A frontal trough continues from this point to 29N26W.

High pressure of 1036 mb located NW of the Azores near 43N42W 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 Sun through Tue. Generally
benign marine conditions are expected across the region through
early next week.

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

$$
GR
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