[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031757
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
157 PM EDT Thu May 3 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
1730 UTC.

...MONSOON TROUGH/ITCZ...

Scatterometer wind data indicate that the monsoon trough extends
from the 07N11W to 03N16W to 02N30W. The intertropical convergence
zone continues from 02N30W to 00N51W. Scattered moderate to strong
convection was occurring within 120 nm N and 240 nm S of the
monsoon trough east of 21W. West of 21W, scattered moderate convection
was located within 120 nm either side of the monsoon trough and
ITCZ to the coast of NE Brazil.

...DISCUSSION...

GULF OF MEXICO...

A ridge extends westward along the Gulf coast to SE Louisiana,
and then continues southwestward to NE Mexico. Moderate to fresh
SE winds are expected to increase to fresh to strong later today
between the ridge to the east and a trough over the southern
Plains. Seas are generally 5 to 7 ft west of 90W and 4 to 5 ft E
of 90W. Winds and seas will diminish later today.

Across the Straits of Florida, E winds of 20 to 25 kt continue.
Seas could reach 7 ft this afternoon due to the persistent long-
fetch easterly winds flowing across the Florida Current. Widely
scattered showers continue between the Florida Keys and Cuba. The
persistent ridge will allow the fresh to strong winds to continue
into tonight with seas reaching 9 ft, before diminishing through
early next week as the ridge weakens.

A weakening surface trough over the SW Gulf and Bay of Campeche is
moving westward. Winds are 10 to 15 kt, but they will increase to
15 to 20 kt by this evening.

CARIBBEAN SEA...

Persistent high pressure north of the area is supporting fresh to
strong trade winds across the south-central Caribbean with seas
of 8 ft. Moderate to locally fresh trades are noted elsewhere.
Increasing winds and building seas can be expected across the
waters E of the Lesser Antilles first, then across the eastern
Caribbean tonight into Fri due to the pressure gradient between
the ridge to the north and a surface trough moving across the
Bahamas. This weather pattern will keep relatively low winds of 15
to 20 kt off the coast of Colombia, and 10 to 15 kt elsewhere
over the western Caribbean. Moisture will remain high across east
and central Cuba through Saturday while gradually spreading
eastward across Hispaniola, keeping the likelihood of scattered to
numerous showers and tstms due to a developing mid-/upper-level
low near the Bahamas drifting southward across eastern and central
Cuba to the north central Caribbean. This unstable weather
pattern could persist through the remainder of the week over the
eastern half of Cuba and parts of Hispaniola as the broad upper-
low meanders over the same area.

ATLANTIC OCEAN...

A stationary front extends from 31N52W to 26N70W in the central
Bahamas. The front becomes diffuse over central Cuba. A surface
extends from 26N70W southward into the Windward Passage. Water
vapor satellite imagery indicates a mid-level low has developed
just north of the Turks and Caicos beneath region of upper- level
divergence associated with a strong westerly subtropical jetstream.
A large area of multi-layer clouds with embedded showers and
tstms was located NE through Se of the mid-level low, with a
general increase in the amount and intensity of the convection
noted during the past 6 hours. Ship and buoy reports, along with
recent scatterometer data indicate winds of 20-25 kt continue
south of the front and east of the trough from near Hispaniola
eastward to 63W. Wind gusts of 35 to 40 kt will be possible in
some of the stronger thunderstorms.

A sharp upper-level trough extends from the north central Atlantic
southward across Bermuda, to the developing mid-level low. Gradual
develop of the low into the upper- and lower-levels is expected
through Saturday as the system drifts southward to eastern/central
Cuba by late Friday. The surface trough is expected to gradually
develop into a broad low pressure system and move WNW between the
Bahamas and Cuba during the next 48 hours, and be near southern
Florida by early Saturday. Active weather spawned by the instability
of this large and complex deep-layer low, along with abundant
moisture drawn northward in a fresh to strong SE wind flow, will
result in numerous showers and thunderstorms steadily developing
and overspreading most of the Greater Antilles, Bahamas, Turks and
Caicos, and adjacent waters by Fri, and gradually spread westward
across the Straits of Florida and into the Florida peninsula over
the weekend. Fresh to strong NE winds are expected ahead of the
trough, and fresh to strong SE winds will follow the trough,
impacting mainly the waters S of 27N-28N and W of 65W.

The remainder of the Atlantic is under the influence of a 1030 mb
high pressure located near the Azores. This system is producing
moderate to fresh trade winds across the deep tropics, where seas
are reaching 6 to 8 ft in NE to E swell.

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

$$
Stewart
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