[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211020
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
620 AM EDT Sun Jun 21 2020

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 0600 UTC surface analysis and satellite imagery through
1020 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is near 27W south of 17N, moving W
near 20 kt. Scattered moderate convection is within 210 nm of the
wave axis from 09N-11.5N. There is no convection north of 12N due
to the presence of the Saharan air layer, which is characterized
by a dry and stable air mass with a dense area of Saharan dust.

The axis of a tropical wave is near 50W south of 17N, moving W
near 20 kt. Scattered moderate showers and isolated tstorms are
within 270 nm of the wave axis from 05N-10N. A stable air mass
associated to the Saharan air layer is limiting convection N of
10N.

The axis of a tropical wave is near 72W, moving W near 20 kt.
Isolated moderate convection is near the wave axis from 15N-17N.

The axis of a tropical wave is near 86W south of 20N, moving W at
10 kt. Isolated moderate convection is seen south of 16.5N and
west of 84W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 12.5N16.5W to 10N22W. The ITCZ
continues from 10N22W to 09.5N25.5W. It resumes from 09N29W to
07N48W, and from 07N53W to 06N57W. Aside from convection
mentioned in the tropical waves section above, scattered moderate
convection is within 180 nm N of the ITCZ between 30W-46W. Similar
convection is within 180 nm of the ITCZ west of 53W.

GULF OF MEXICO...

A 1018 mb surface high is centered over the NE Gulf of Mexico
near 28N86W. Scattered showers and isolated tstorms are seen
over the SE Gulf of Mexico to the N of Cuba and over the Florida
Straits. Gentle to moderate winds prevail over much of the Gulf
waters, except in the vicinity of the high pressure center where
light to gentle winds prevail.

Surface ridging will prevail over the Gulf waters through the
forecast period. Gentle to moderate easterly winds and slight seas
are expected today. Moderate to fresh southerly winds are
forecast over the western Gulf Mon night through Thu night as the
pressure gradient tightens between the ridge and lower pressure
over Mexico.

CARIBBEAN SEA...

As typical for this time of year, tropical waves are traversing
the Caribbean waters. Please see the tropical waves section
above.

Strong to near gale force winds prevail across the south central
Caribbean. Moderate to fresh winds prevail elsewhere across the
Caribbean, except for the far NW Caribbean where gentle to
moderate winds prevail. Isolated tradewinds showers are noted over
the Caribbean waters. The GOES-16 Saharan Air Layer tracking
product shows that a large, westward-moving plume of dense Saharan
dust is moving across the eastern Caribbean Sea. The leading edge
of this plume has reached 64W and is expected to continue
spreading westward.

Fresh to strong trades over the south-central Caribbean will
expand to the north-central and southwest basin through the middle
of the week as high pressure builds over the western Atlantic.
Winds will pulse to near gale force near the coast of Colombia
each night through Thu night with seas building to near 12 ft with
the strongest winds. Fresh to strong winds are expected in the
Gulf of Honduras tonight through Thu night.


ATLANTIC OCEAN...

Scattered moderate convection is noted from 26N-32N between 62W-
70W. Isolated moderate convection is also seen east of the coast
of central Florida. A surface trough extends from 32N48W to low
pressure of 1020 mb near 31N51W to 25N56W. Scattered moderate
isolated strong convection is within 300 nm east of the trough. A
large plume of Saharan dust continues to spread across the
tropical waters. The Saharan dust appears to be particularly dense
from 10N-20N between 40W-60W, with a second surge seen between
Africa and 30W. Moderate to fresh tradewinds prevail south of 20N.
Gentle to moderate winds prevail N of 20N.

High pressure will prevail across the offshore waters of the
western Atlantic Ocean through the next week. Fresh to
occasionally strong easterly winds will pulse north of Hispaniola
at night through Thu night.

$$
AL/Hagen
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