[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231021
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
621 AM EDT Tue Jun 23 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.

...SPECIAL FEATURES...

Subtropical Depression Four is centered near 39.3N 63.4W at
23/0900 UTC or 320 nm S of Halifax Nova Scotia moving NE at 11
kt. Estimated minimum central pressure is 1008 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Scattered
moderate isolated strong convection is within 150 nm southeast
semicircle of the center.

Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for
more
details.

...TROPICAL WAVES...

The axis of a tropical wave is near 40W south of 18N, moving W at
20 to 25 kt. Scattered moderate convection is seen from 06N-11N
within 180 nm of the wave axis.

The axis of a tropical wave is near 77W south of 17N, moving W at
25 to 30 kt. A stable air mass associated with a dense plume of
Saharan dust is limiting significant convection with this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 16N16.5W to 10N26W. The ITCZ
continues from 10N26W to 08N36W. It then resumes from 07N42W to
04N51W. Scattered moderate convection is noted within 210 nm N
and within 60 nm S of the ITCZ between 44W-51W.

GULF OF MEXICO...

An upper-level low over the northwest Gulf of Mexico near 28N94W
is enhancing upper-level diffluence over the north-central Gulf in
a moist environment. Scattered moderate isolated strong convection
is seen north 26N between 85W-92W. Scattered moderate convection
is elsewhere W of 90W. High pressure of 1019 mb is centered near
26N83W. Moderate to fresh winds prevail over the western Gulf.
Gentle to moderate winds prevail over the SE Gulf, and light to
gentle winds prevail in the vicinity of the high pressure center.

Surface ridging will prevail over the Gulf waters through the
forecast period. Moderate to fresh southerly winds are forecast
over the western Gulf through Thu night due to the pressure
gradient between the ridge and lower pressure over Mexico.

CARIBBEAN SEA...

GOES-16 satellite imagery shows dense Saharan dust covers most of
the Caribbean. This dry, stable air mass is inhibiting convection
across the region. The exception is the far SW Caribbean, where
the east Pacific monsoon trough is enhancing scattered moderate
to strong convection south of 10N and west of 80W, including over
portions of Panama. At the surface, the pressure gradient between
high pressure north of the area and climatological low pressure
over Colombia is producing fresh to strong trades across central
Caribbean, reaching near gale force near the coast of Colombia.
Fresh to strong winds prevail over the Gulf of Honduras, and
moderate winds are noted over the remainder of the NW Caribbean.
Fresh winds prevail over the eastern Caribbean.

Fresh to strong trades will prevail across the central Caribbean
through the week. Winds will pulse to near gale force off the
coast of Colombia each night through Sat night with seas building
to 12 ft and higher during the strongest winds. Fresh to strong
winds are expected in the Gulf of Honduras through Sat night.

ATLANTIC OCEAN...

See section above for information on Subtropical Depression Four.

A broad surface ridge covers the western Atlantic, with light to
gentle wind speeds north of 22N west of 60W. Scattered moderate
isolated strong convection is offshore northern Florida from 26N-
32N between 79W-81W. Farther east, a surface trough extends from
32N50W to 26N52W to 22N57W. Isolated showers are near the trough
axis. Another surface trough extends from 30N40W to 23N40W.
Isolated showers are near the trough axis. In the tropics, fresh
trades prevail S of 20N.

High pressure extends from the central Atlantic to Florida and
will prevail across the offshore waters through Saturday. Fresh
to occasionally strong easterly winds will pulse across the
waters north of Hispaniola each night through Sat night.

$$
AL/Hagen
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