[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182208
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Tue May 18 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
2200 UTC.

...SPECIAL FEATURES...

...GALE WARNING OFF THE COAST OF MOROCCO...

Meteo-France is continuing a gale warning for the eastern portion
of the Agadir area off Morocco through at least 0900 UTC, with
rough to very rough seas. Refer to the Meteo-France High Seas
Forecast at http://www.gmdss.org/II.html for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Guinea near
11N15W to 07N20W. The ITCZ continues from 07N20W to 03N37W to
off the coast of French Guiana near 05N51W. Scattered moderate
to strong convection is noted from 03N to 07N between 13W and
21W.

GULF OF MEXICO...

A squall line is evident over the north central Gulf. Showers and
thunderstorms are noted in an arc extending from 60 nm off
Mobile Bay to 120 nm off Vermilion Bay, Louisiana. The dynamics
aloft supporting these thunderstorms are related to a deep layer
low pressure area moving through the southern Rockies. At the
surface, recent scatterometer data indicate moderate to fresh E
to SE winds over the eastern Gulf, between high pressure over the
Carolinas and a trough over northeast Mexico. Seas are generally
4 to 6 ft across the basin.

For the forecast, the high pressure over the Carolinas will
continue to dominate the eastern Gulf waters the remainder of
the week. The pressure gradient between the high pressure and a
deepening low pressure across the Southern Plains and northern
Mexico will result in an increase in winds and seas across the
Gulf region later today through Fri. Under this weather pattern,
expect fresh to strong E to SE winds, and building seas of up to
10 or 11 ft Thu and Fri. Similar marine conditions are expected
in the Straits of Florida.

CARIBBEAN SEA...

High pressure centered off the Carolinas and extending southward
through the Bahamas is supporting only moderate trade winds
across the Caribbean, with fresh trade winds over the southeast
and south-central Caribbean, and off the coast of central
Honduras. Seas are generally 4 to 6 ft in most areas. A few
thunderstorms are active off western Cuba, near the end of a
stationary front over central Cuba.

For the forecast, the weak high pressure will continue to maintain
moderate to fresh tradewinds across the basin through Wed. Trade
winds will increase basin wide Wed night through Sun night as
high pressure builds across the western Atlantic. Expect fresh to
strong easterly winds in the Gulf of Honduras mainly at night
through Thu night.

ATLANTIC OCEAN

A cold front reaches from 31N42W to 24N52W then is stationary
through the southern Bahamas to central Cuba. Moderate to fresh
NE to E winds are noted west of 60W with 4 to 6 ft in open
waters. A few showers and thunderstorms are active along the
front. Light to gentle breezes are evident west the front to 60W.
Seas are 7 to 10 ft however in this area. This is due to
northerly swell associated with a 1004 mb low centered north of
the area near 39N39W. Farther east, a ridge extends from 1028 mb
high pressure near 43N15W to 25N40W. Outside of the strong to
gale force winds off Morocco mentioned in the Special Features
section, this pattern is supporting generally moderate to fresh
NE to E across the remainder of the basin. Seas are 3 to 5 ft in
ridge axis, 5 to 7 ft elsewhere, except higher in the area of
gales off Morocco. Satellite imagery suggests an area of
suspended African dust across the tropical Atlantic south of 20N
from the West African coast to 40W.

For the forecast for west to 65W: the stationary front will
gradually become aligned E to W along 22N/23N through Thu then
sink southward, approaching Puerto Rico and the Leeward Islands
by Fri night. The pressure gradient between high pressure off of
Cape Hatteras and the frontal boundary will support an area of
fresh to strong easterly winds N of the front and W of 68W Wed
through Fri with seas peaking around 10 or 11 ft E of the Bahamas
late Wed through early Thu.

$$
Christensen
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