[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181756
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

...METEO-FRANCE GALE-FORCE WIND WARNING OFF THE COAST OF
MOROCCO...

The surface pressure gradient between the 1026 mb Azores high
pressure center that is near 35N22W and the comparatively lower
surface pressures in West Africa is supporting gale-force winds
in the METEO-FRANCE forecast area, that is called AGADIR. The
sea heights there are ranging from 9 to 11 feet. The winds are
forecast to diminish below gale-force at 19/0000 UTC. Please,
refer to the Meteo-France High Seas Forecast, which is on the
website: www.meteofrance.com/previsions-meteo-
marine/bulletin/grandlarge/m etarea2, or the website:
http://www.gmdss.org/bulletins/METAREA2.HIGH_SEAS_WARNING.0635.18
06352524849.html for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Guinea near
10N14W to 05N25W. The ITCZ continues from 05N25W to 03N36W to
the NE coast of Brazil near 04N51W. Scattered moderate to strong
convection is noted from 01N to 08N between 05W and 24W.
Scattered moderate convection is noted within 200 nm of the ITCZ
between 37W to 49W.

GULF OF MEXICO...

Weak surface ridging continues across the northeastern Gulf of
Mexico due to high pressure located over the mid-Atlantic
states. An ASCAT pass at 1500 UTC revealed fresh SE winds across
most of the basin associated with the pressure gradient. Seas
are 5 to 7 ft across the basin.

A broad area of diffluence and middle level troughing over the
Gulf continues to interact with the moist return flow at low
levels and is producing clusters of strong convection across SW
Louisiana and within 150 nm offshore SE of the Louisiana and
Mississippi coastlines. A similar area of scattered convection
is north of the Yucatan Channel from 22N-25N between 85W-88W.

For the forecast, high pressure along the middle Atlantic coasts
extending SW to the NE Gulf will remain generally stationary
throughout the week. Winds will increase to fresh to strong late
today through Fri as low pressure deepens across the Southern
Plains and northern Mexico.

CARIBBEAN SEA...

High pressure across the NE Atlantic extends W-SW across the
central Atlantic and weakly north of the NE Caribbean. The
associated pressure gradient is producing moderate to fresh
tradewinds across the basin. Generally fair weather prevails
across most of the basin under the stable influence of an upper
level ridge. Widely scattered moderate convection is seen across
the coastal waters of Cuba, north of 20N, due to associated
moisture from a stationary front extending from the central
Bahamasacross central Cuba. Seas are 3 to 5 ft over most of the
basin, the exception being off Colombia and NW Venezuela where
seas are 5 to 7 ft.

The monsoon trough extends into the basin from the eastern
Pacific ocean through Panama. Scattered strong convection is
within 100 nm offshore of Panama and NW Colombia.

For the forecast, the high pressure across the NE Atlc will
maintain moderate to fresh tradewinds across the basin through
Wed. Trade winds will increase basin wide Wed night through Sat
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 lingering cold front extends from 31N44W to 25N54W to 24N55W
then becomes stationary to the central Bahamas to central Cuba.
Scattered showers and thunderstorms are within 100 nm of the
front. High pressure over the middle Atlantic coasts is
supporting moderate to fresh E-NE winds to the north of the
stationary front and west of 55W, where seas are 5 to 7 ft. East
of 50W, winds ahead of the cold front are fresh to locally
strong from the S-SW.

For the forecast west of 65W, the stationary front will
gradually become aligned E to W along 23N through Thu then sink
southward to 21Nand dissipate 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
morning, with seas peaking around 11 ft E of the Bahamas late
Wed through early Thu.

Farther east, an elongated ridge axis extending from a 1026 mb
high centered near 35N22W is allowing for gentle to moderate
anticyclonic flow, except for near the Canary islands where NE
winds become fresh. Moderate trades prevail elsewhere. Satellite
imagery suggests an area of suspended African dust across the
Tropical Atlantic south of 17N from the W African coast to 40W.

$$
Mora
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