[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101718
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
118 PM EDT Sat Aug 10 2019

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 in the east Atlantic is along 32W from 03N-21N,
moving W at 10-15 kt. Model diagnostics depict the wave well at
700 mb. Scattered showers are seen south of 08N within 300 nm E of
the wave axis.

A central Atlantic tropical wave is along 56/57W from 03N-20N,
moving W at at 10-15 kt. The wave is well depicted by model
diagnostics at 700 mb. The wave is embedded in dry, dusty air
from the Sahara, which is inhibiting convection north of 11N.
Isolated showers and tstorms are from 04N-11N between 50W-59W.
Expect scattered showers across portions of the Windward Islands
Sunday into Monday.

A central Caribbean tropical wave is along 73W from 07N-22N from
the SE Bahamas to Haiti to E Colombia, moving W at 10-15 kt. The
Saharan Air Layer outbreak over the eastern Caribbean has reached
74W, and all convection associated with this wave over the
Caribbean has dissipated. Isolated showers and tstorms are seen
over NW Venezuela and near the SE Bahamas.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of The Gambia near
13N17W to 09N25W to 09N30W. The ITCZ extends from 09N34W to 09N45W
to 07N55W. Aside from the showers associated with tropical waves
mentioned in the section above, scattered moderate convection is
seen from 07N-11N between 17W-21W. Isolated moderate convection
is within 210 nm S of the ITCZ between 37W-49W.

GULF OF MEXICO...

Mid to upper level ridging covers most of the Gulf of Mexico,
especially the northwestern and central Gulf. In the low levels,
weak ridging prevails over the southeastern and central Gulf. A
1016 mb surface high is analyzed near the Dry Tortugas. An area of
moisture over Arkansas associated with a frontal system is being
advected southeastward by NW winds in the 600-300 mb level. This
moisture is moving over portions of the eastern Gulf of Mexico.
Scattered showers and isolated tstorms are seen from 27.5N-29.5N
between 85W-89.5W, and from 26N-28N east of 85W. Isolated showers
are elsewhere north of 24N and east of 90W. Isolated showers are
also noted over the central Bay of Campeche. Most of the western
Gulf west of 90W north of 21N is under subsidence with clear to
partly cloudy skies. Gentle winds cover much of the Gulf, with
moderate SE winds over the western Gulf west of 93W.

Weak high pressure will remain across the central and eastern
Gulf allowing for gentle to moderate winds and relatively slight
seas through mid week. Moderate to fresh winds will pulse each
night off the NW coast of the Yucatan Peninsula in association
with a local trough.

CARIBBEAN SEA...

Refer to the Tropical Waves section above for information on the
tropical wave currently over the Central Caribbean.

An upper-level low is centered near 18N79W with an upper trough
axis extending toward the Turks and Caicos Islands. Only an
isolated shower or two is noted near the Windward Passage and
eastern Cuba. Upper-level ridging covers the eastern Caribbean.
Dry Saharan Air also covers the eastern Caribbean from 60W-74W,
with little to no shower activity seen. In the SW Caribbean, the
East Pacific monsoon trough has its axis along Panama's latitude.
Scattered moderate convection is possible south of a line from
09N76.5W to 11N84W. Isolated showers and tstorms are seen
elsewhere south of 13N west of 81W. The latest ASCAT pass shows
strong trades over the south-central Caribbean from 12N-15N
between 72W-77W, with fresh trades over the remainder of the
central Caribbean south of 17.5N.

The passage of the waves along with high pressure north of the
area will continue to support fresh to strong winds in the central
and southwest basin, increasing to near gale force at night.

ATLANTIC OCEAN...

An upper-level trough axis extends from 31N59W to 24N66W. Another
larger upper-level trough in the mid-latitudes comes as far south
as 29N between 65W-75W. Low-level SW winds are advecting abundant
moisture toward the region, and there are several areas of
enhanced upper-level divergence and upper-level diffluence near
the upper troughs. These factors are leading to scattered to
numerous moderate convection, seen within 120 nm of a line from
23N68W to 27N67.5W to 31N62W. Scattered showers and tstorms are
occurring within 60 nm of a second line, stretching from Grand
Bahama Island to 29N72W to 31N68W.

Farther east, a 1022 mb high is near 28N42W and a 1021 mb high is
near 27N33W. In between the two highs, a surface trough stretches
from 29N34W to 24N42W to 23N46W to 21N54W. A 1018 mb surface low
is near 30N29W. The trough and low are not producing any
significant weather.

A ridge of high pressure will persist from the central Atlantic
across the northern Bahamas to the Straits of Florida through mid
week. This pattern will maintain gentle to moderate winds north of
22N, and moderate to fresh winds south of 22N, pulsing to strong
off Hispaniola late Sun.

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

$$
Hagen
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