[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281707
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
107 PM EDT Sun May 28 2017

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
1700 UTC.

...TROPICAL WAVES...

A tropical wave is located over Guinea in W Africa and the
adjacent Atlc waters. The axis of the wave extends from 12N14W to
03N14W. The wave is moving W at 10 to 15 kt. TPW satellite imagery
shows the wave is embedded in moderately moist environment. This
wave possesses a good signature in the 700 mb wind flow field.
Scattered moderate and isolated strong convection is present from
03N to 06N between 10W and 13W.

A tropical wave located over the eastern Atlc has an axis
extending from 09N31W to 00N31W. The wave is moving W at 15 kt.
TPW satellite imagery shows the wave is embedded in deep layer
moisture near the ITCZ. The wave lies just to the S of large area
of dry air associated with the Saharan Air Layer to the N of 10N.
This wave possesses a weak signature in the 700 mb wind flow
field. Scattered moderate and isolated strong convection is seen
from 00N to 04N between 27W and 33W.

A tropical wave over the central Atlc has an axis extending from
14N49W to 03N48W. The wave is moving W around 30 kt. TPW satellite
imagery shows the wave is embedded a moderately moist environment
near the ITCZ. Dry air associated with the Saharan Air Layer N of
the wave to the N of 10N. This wave possesses a weak signature in
the 700 mb wind flow field. There is no significant convection
currently associated with this wave.

A tropical wave over the western Atlc has an axis extending from
15N59W to 07N60W. The wave is moving W at 20 to 25 kt. This wave
shows a well defined inverted-V surface reflection on satellite
imagery. TPW satellite imagery shows the wave is embedded in a
moist environment. This wave possesses a weak signature in the 700
mb wind flow field. Scattered moderate and isolated strong
convection is found over the Lesser Antilles from 14N to 17N
between 58W and 63W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough enters the tropical Atlc from the coast of
Guinea in West Africa near 10N14W and continues to 07N17W. The
ITCZ continues from 07N17W to 03N29W, then resumes W of a tropical
wave near 03N33W to 03N40W to 06N46W. The ITCZ resumes again W of
another tropical wave near 06N51W to the coast of South America
near 06N54W. Other than the convection associated with tropical
waves, scattered moderate and isolated strong convection is taking
place within 60 nm either side of a line from 02N34W to 06N42W.

...DISCUSSION...

GULF OF MEXICO...

A 1017 mb high lingers over the NE Gulf of Mexico near 26N84W.
Light to gentle anticyclonic winds are present beneath the high
over the NE Gulf. Moderate SE to S surface winds are observed over
the Gulf to the W of 90W between the high and a surface trough
over interior Mexico. In the upper levels, a broad mid to upper-
level ridge extends over the Gulf from the Yucatan to the Florida
Big Bend. Strong subsidence beneath the ridge is inhibiting
convection over the Gulf. This weather pattern will continue
through Monday, although a slow moving frontal boundary extending
east- northeastward from Texas to the SE United States could
trigger showers and thunderstorms near the northern Gulf Coast for
the nest couple of days.

CARIBBEAN SEA...

A tropical wave is approaching the E Caribbean. See the tropical
waves section for additional details. The monsoon trough extends
eastward from the NE Pacific over Costa Rica, Panama and Northern
Colombia. Converging low-level winds just N of the trough are
producing scattered moderate and isolated strong convection over
the far SW Caribbean from 09N to 11N between 76W and 83W. An
upper-level ridge extends E over the SW Caribbean from the NE
Pacific. A broad upper-level trough reaches SW over the Central
Caribbean from the NW Atlc. Strong subsidence on the W side of the
trough is limiting convection over most of the Caribbean. Upper-
level divergence on the E side of the trough is aiding convection
over the far eastern Caribbean. Expect over the next 24 hours for
the tropical wave to move W from the Atlc and introduce more
showers and thunderstorms to the eastern Caribbean. Convection
associated with the Monsoon Trough will continue over the SW
Caribbean and Central America.

HISPANIOLA...

Water vapor imagery shows strong subsidence on the W side of an
upper- level trough has moved over the Island. This subsidence
will continue hindering convection through Monday. However, the
tropical wave entering the Eastern Caribbean should provide a more
favorable environment for showers and thunderstorms by Tuesday.

ATLANTIC OCEAN...

A weakening warm front extends SW over the W Atlc from 31N59W to
the central Bahamas near 23N73W. No significant convection
accompanies this feature. A broad 1024 mb high is centered over
the central Atlantic near 29N44W. This system is maintaining fair
weather over most of the basin and moderate trade winds N of the
ITCZ to 20N. A cold front extends SW over the E Atlantic from
31N19W to 29N26W, then continues as a weakening cold front to
27N34W to 29N40W. Only shallow cloudiness and isolated showers
are present within 60 nm either side of this boundary. Expect over
the next 24 hours for both the W Atlantic front and the E
Atlantic front to dissipate. Four tropical waves are passing over
the tropical Atlc. Please refer to the Tropical Waves section for
more details. An expansive area of Saharan dry air and dust
spreads eastward from Africa across much of the Atlantic Ocean N
of 10N and E of 50W.

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

$$
McElroy
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