[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041730
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
130 PM EDT Thu Jul 4 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
1715 UTC.

...TROPICAL WAVES...

A tropical wave has an axis along 34W from 03N-18N, moving W
around 15 kt. A cluster of moderate convection is observed behind
the wave axis, and where the wave meets the monsoon trough. This
convective activity covers from 05N-10N between 30W-34W. The wave
shows up well in model diagnostics and the TPW product. Some of
the usual summertime African dust surrounds the wave based on
GOES-R RGB Geocolor imagery and the Saharan Air Layer product from
CIMSS.

A well defined tropical wave is just E of the Lesser Antilles.
Its axis is along 58W south of 18N to near the Guyana/Suriname
border, moving W at 15-20 kt. The TPW product shows a large area
of moisture related to this wave. Scattered moderate convection is
noted on either side of the wave axis from 11N-15N between 54W-
61W. The Windward Islands are already reporting some shower
activity with gusty winds in association with the wave, forecast
to impact the Lesser Antilles the rest of today, and Puerto Rico
and the UK/US Virgin Islands on Fri, bringing enhanced showers and
thunderstorms with gusty winds. Moisture associated with this
wave will likely reach Hispaniola late Fri into Sat. In addition,
this wave is forecast to strengthen the trades across most of the
basin through Sat as it passes across the forecast area, then
reach Central America Sun.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
12N16W to 08N25W to 06N37W. The ITCZ continues from 06N37W to
04N51W. Aside from the convection associated with the tropical
waves, scattered moderate convection is seen within about 120 nm S
of the monsoon trough between 18W-30W.

GULF OF MEXICO...

Deep-layered ridge prevails across the entire Gulf of Mexico. As
of 1500 UTC, a surface high of 1018 mb is analyzed near the mouth
of the Mississippi River. Under the influence of this system,
mainly light to gentle winds prevail, with seas generally under 4
ft, with the exception of gentle to moderate southerly winds and
seas on the 3 to 5 ft range over the NW and west-central Gulf. A
surface trough extends from near Tampa Bay, FL across the SE Gulf
into western Cuba. Scattered showers and tstms are associated with
this trough, forecast to drift westward across the eastern half
of the Gulf on Fri. No significant convective activity is noted
elsewhere across the Gulf waters.

Weak high pressure will continue to dominate the region through
the upcoming weekend, resulting in gentle to moderate winds across
the Gulf. A trough will develop over the Yucatan Peninsula during
the afternoon and move westward into the Bay of Campeche each
evening, bringing a brief period of fresh to locally strong winds
to the S central Gulf.

CARIBBEAN SEA...

A tropical wave is just E of the Lesser Antilles. Please, sea
Tropical Waves section for more details.

The most recent scatterometer pass indicates fresh to strong
trade winds across the south-central Caribbean, with seas to near
9 ft based on altimeter data. Moderate to fresh winds are noted
elsewhere across the E and central Caribbean as well as over the
waters E of the Lesser Antilles, with gentle to moderate winds
across the NW Caribbean. The pressure gradient between the Bermuda
high and the Colombian/Panamanian low will continue to support
fresh to strong trade winds across the south-central Caribbean
through the weekend. These winds are also forecast to be enhanced
by the passage of the above mentioned tropical wave.

Scattered showers and thunderstorms are developing S of Cuba.
A diffluent pattern aloft between a ridge over the Gulf of Mexico
and an upper-level low spinning over the central Caribbean is
helping to induce this convective activity. Shallow moisture
embedded in the trade wind flow is noted elsewhere due to the
presence of Saharan dust.

ATLANTIC OCEAN...

A surface trough extends from 30N72W to 27N73W based on a recent
ASCAT pass. Isolated showers prevail near the trough. The
remainder of the Atlantic Ocean is under the influence of the
Bermuda-Azores high, anchored by a 1028 mb high near 34N38W. This
system extends a ridge westward towards the Bahamas and Florida.
Moderate to fresh easterly winds are noted across the southern
periphery of the ridge. Little change in this weather pattern is
expected over the next several days. Fresh to strong winds are
expected N of Hispaniola Fri and Sat as the aforementioned
tropical wave moves through the central Caribbean.

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

$$
GR
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