[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162324
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Mon May 17 2021

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Gale Warning E of 35W: The pressure gradient between a high
pressure center located between the Madeira and the Azores
Islands and lower pressures over West Africa will support fresh
to strong N to NE winds N of 25N and E of 20W, including the
Canary Islands. Meteo-France has issued a Gale Warning for Agadir
from 17/15 UTC to 18/00 UTC at least. The forecast calls for N
or NE winds Force 8 in the Beaufort Wind Scale with gusts. Seas
are forecast to build to 9-12 ft with the strongest winds by
18/00 UTC. For more details, refer to the Meteo-France High Seas
Forecast listed on their web-site: www.meteofrance.com/
previsions-meteo-marine/bulletin/grandlarge/metarea2.

...MONSOON TROUGH/ITCZ...

The monsoon trough exits western Africa from the coast of
Guinea-Bissau near 12N16W then continues SW to 05N21W. The ITCZ
extends from 05N21W to 03N35W to 07N52W. A cluster of moderate to
strong convection is affecting parts of Liberia, southern Guinea
and Sierra Leone. In addition, numerous moderate to isolated
strong convection is observed to the south from 02N-07N between
10W-13W. This convective activity could be associated with a
tropical wave. Scattered moderate convection is from 02N to 08N
between 15W-30W.

GULF OF MEXICO...

Showers and thunderstorms are affecting the coast of Texas and
the NW Gulf. The atmospheric ingredients responsible for this
convective activity are a diffluent pattern aloft over the NW
Gulf of Mexico and abundant low level moisture in a southerly
wind flow over the western Gulf. The most recent ASCAT pass shows
fresh SE winds over the western Gulf, mainly north of 21N and
west of 94W with higher winds near the coast of Texas likely due
to the presence of strong thunderstorms. Moderate to fresh NE to
E winds are noted over the eastern Gulf, including the Florida
Keys and the Straits of Florida. Seas are generally in the 3-5
ft range with the exception of 5-7 ft in the Straits of Florida.
A ridge dominates much of the Gulf region.

For the forecast, high pressure across the SE U.S. will shift
slowly into the western Atlantic through Tue, supporting
moderate to fresh E to SE winds over the basin. Winds will
increase to fresh to strong late Tue through Thu as the pressure
gradient tightens between the Atlantic ridge and a deepening low
pressure across the Southern Plains. Seas are forecast to build
to 7-10 ft across parts of the Gulf during this time frame. In
the Straits of Florida, winds are expected to increase to 20-25
kt with building seas of 7-10 ft Wed and Wed night.

CARIBBEAN SEA...

Based on recent satellite derived wind data fresh to strong trade
winds are noted over the south-central Caribbean, particularly
from 11N-13N between 72W-76W. Gentle to moderate winds are seen
elsewhere. Seas are 5-8 ft offshore Colombia, 3-5 ft south of 16N
E of 82W, and 2-4 ft elsewhere.

Convection has flare-up this afternoon over most of Cuba and
over parts of Hispaniola and Jamaica. Scattered showers and
thunderstorms are also noted over the northern Yucatan peninsula.
Dry air and mostly clear skies prevail over the eastern Caribbean,
including Puerto Rico due to the presence of Saharan dust. It is
confirmed by the Saharan Air Layer tracking product from CIMSS.

For the forecast, the ridge N of the Caribbean Sea will shift
eastward and weaken, diminishing winds and seas modestly through
Mon. Trade winds will increase basin wide Wed night through Thu
night as high pressure builds across the W Atlantic.

ATLANTIC OCEAN...

A cold front extends from a 1005 mb low pressure located E of
Bermuda near 32N61W to 25N72W. A shear line is analyzed from
25N72W across the central Bahamas and west-central Cuba. A band
of showers with embedded thunderstorms is ahead of the front E
of 67W. High pressure follows the frontal boundary. The latest
ASCAT pass shows moderate to fresh northerly winds in the wake of
the front. Moderate to fresh NE winds are also occurring just
east of Florida. Seas of 8-9 ft are seen just behind the front
mainly N of 30N between 62W-66W. The low pressure is forecast to
intensify and move ENE over the next 24 hours while the front
will drift SE and dissipate through Tue. Winds will increase
north of 24N and west of 68W late Tue through Thu as high pressure
builds across the W Atlantic.

Over the central Atlantic, fresh to strong winds and seas of
8-11 ft associated with the strengthening low pressure E of
Bermuda will affect mainly the forecast waters from 28N-31N
between 53W-65W by tonight. N of 31N, gale force winds and higher
seas are expected.

The remainder of the Atlantic forecast waters are under the
influence of a ridge with a 1024 mb high pressure situated near
33N26W. Moderate to fresh trades are noted per scatterometer data
across the tropical Atlantic. A Gale Warning is in effect E of
35W. Please, see Special Features section for details.

$$
GR
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