[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101657
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1257 PM EDT Sun Jun 10 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...

Currently, three tropical waves are observed between the coast of
Africa and the Lesser Antilles.

A tropical wave is added to the 1200 UTC analysis/surface map
along 18W from 4N-12N. The Hovmoller Diagram clearly indicates
the westward propagation of the wave, and model diagnostics
guidance also suggests the presence of this system. This wave
shows up well as a low amplitude moisture surge on the TPW
product. A cluster of moderate to strong convection is seen along
the wave's axis from 7N-9N between 17W-19W. Scattered moderate
convection is noted elsewhere from 4N-9N between 15W-19W.

A tropical wave is along 31W from 4N-13N moving westward 15 to 20
kt. This wave shows up well as a low amplitude moisture surge on
the TPW product. Scattered showers are near the southern end of
the wave's axis. Saharan dust surrounds the wave.

Another tropical wave is relocated farther west along 44W based
on the TPW animation. Now, the wave coincides with a good surge of
moistened air. An area of isolated to scattered moderate convection
is along the wave's axis from 7N-9N between 43W-46W.

A tropical wave is moving across the eastern Caribbean. Its axis
is along 67W south of 19N, moving westward at 15 kt. A patch of
low level moisture with embedded showers is associated with the
wave, forecast to reach Hispaniola this afternoon.

A tropical wave is moving across the Yucatan Peninsula and
northern Central America, with axis along 88W. The wave is
interacting with an upper-level trough resulting in continued
thunderstorm development across parts of the western Caribbean and
northern Central America, and the Yucatan Peninsula, particularly
in afternoon and early evening hours.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through Guinea near 10N14W to 06N30W.
The ITCZ continues from 05N32W to 06N42W to the coast of Guyana
near 07N59W. Scattered moderate to isolated strong convection is
from 04N-09N between 14N-19N. Outside the convection associated
with the tropical waves, scattered moderate convection is noted
within about 120 nm N of ITCZ between 35W-38W, and within 60 nm N
of the ITCZ axis W of 56W.

...DISCUSSION...

GULF OF MEXICO...

A mid to upper level trough extending across the eastern Gulf and
the far NW Caribbean into northern Central America continues to
enhance the development of scattered showers and thunderstorms
across the eastern Gulf, and over parts of Florida. Similar
convective activity is also noted along the northern Gulf waters
from Louisiana to the Florida Panhandle. The remainder of the Gulf
is under the influence of the Atlantic ridge that extends westward
across Florida into the Gulf, with a 1019 mb high pressure centered
near 28N87W.

The mid to upper trough will meander over the Gulf of Mexico
through the middle of the week and continue to enhance convection
across the eastern Gulf waters, and over parts of Florida. A
surface trough will develop along the Yucatan Peninsula late each
afternoon, drift westward across the southwest Gulf during the
overnight hours accompanied by a fresh east to southeast wind
shift and dissipate along 95W/96W during the late mornings. An
east to west ridge will meander across the northern Gulf waters
through the period accompanied by moderate to locally fresh return
flow. The pressure gradient will tighten during the middle of the
week with mostly fresh southeast flow forecast across the entire
southwest Gulf.

CARIBBEAN SEA...

Recent scatterometer data provide observations of fresh to strong
winds across the central Caribbean, and the eastern Caribbean S of
15N. The most recent altimeter data indicated sea heights of near
10 ft in association with these winds. Moderate to locally fresh
trades prevail across the remainder of the eastern Caribbean, with
gentle to moderate NE-E winds across the NW part of the basin.
The pressure gradient between high pressure N of area and the
Colombian/Panamanian low will continue to support fresh to strong
winds across the central Caribbean, and the eastern Caribbean S of
15N, but mainly W of 64W. These conditions will persist through
early Tue, then expand north and across the NW Caribbean waters
Tue night through Thu.

Strong SW flow ahead of a mid to upper-level trough over the
eastern Gulf of Mexico and the far NW Caribbean continues to
transport abundant mid to upper level moisture across the NW
Caribbean into west-central Cuba and the Bahamas. Areas of showers
with embedded tstms are observed over the NW Caribbean. Shallow
moisture embedded in the trade wind flow is noted elsewhere
across the basin. Visible satellite picture from GOES-16 and the
Saharan Air Layer from CIMSS indicates the presence of African
dust across the eastern Caribbean.

ATLANTIC OCEAN...

Abundant moisture continues to prevail across the west Atlantic
and the Bahamas, on the eastern side of the Gulf of Mexico-NW
Caribbean mid to upper-level trough. Lightning data and Doppler
Radar indicate the presence of tstms over S Florida and the NW
Bahamas. A ridge dominates the remainder of the Atlantic Ocean
with a 1026 mb high pressure located near 35N28W. Moderate to
locally fresh winds are noted along the southern periphery of the
ridge per scatterometer data.

An east to west ridge is forecast to meander between 27N and 29N
through Thu. Fresh to locally strong easterly winds are
forecast along the northern coast of Hispaniola during the late
afternoons and evenings, with moderate easterly flow forecast
elsewhere south of the ridge. Gentle to moderate southerly flow
is expected north of the ridge.

The Saharan Air Layer (SAL) from CIMSS shows abundant Saharan dust
covering the area between the west coast of Africa and the Lesser
Antilles.

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

$$
GR
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