[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211022
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed Jul 21 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 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

Caribbean Gale Warning: The pressure gradient between the
Atlantic ridge and the Colombian/Panamanian low is supporting
gale force winds off the coast of the Colombia and in the Gulf of
Venezuela through 12Z today, and again tonight. Seas are forecast
to build up to 12-16 ft with the strongest winds across the
south-central Caribbean. For more information, please see the
High Seas Forecast issued by the National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml

...TROPICAL WAVES...

An Atlantic tropical wave extends its axis along30 and south of
21N, moving west at 10 to 15 kt. Scattered moderate convection is
noted where the wave meets the monsoon trough from 07N to 11N
between 28W and 34W.

A second tropical wave extends it axis along 51W from 20N
southward, moving westward at 10 to 15 kt. Subsidence and dry air
associated with the Saharan Air Layer surrounds the most of the
area of the wave. Scattered showers are noted from 10N to 13N
between 46W and 50W.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean through Senegal and
extends from 13N17W to 09N48W. The ITCZ extends from 09N52W to
09N60W. Aside from the convection related to the tropical waves
described above, scattered moderate convection is noted from 06N
to 12N between 18W and 46W.

...GULF OF MEXICO...

The Gulf is under the influence of the Atlantic ridge that
extends westward across Florida into the eastern Gulf producing
light to gentle anticyclonic flow. Seas are in the 1-3 ft range
across the entire basin, however winds and seas could be higher
near thunderstorms.

For the forecast, the ridge will continue to sink southward
through the forecast period, providing tranquil conditions across
the Gulf of Mexico for the remainder of the week. Moderate to
fresh E to SE winds will pulse tonight to the NW of the Yucatan
Peninsula and continue through the end of the week.

...CARIBBEAN SEA...

A Gale Warning is in effect for the south-central Caribbean.
Please, see the Special Features section for details.

The most recent scatterometer data depict fresh to strong trades
prevailing across most of the central Caribbean with seas of 8-10
ft. Elsewhere in the basin, moderate to fresh trades prevail with
5-8 ft seas, except in the NW Caribbean where trades are gentle
to moderate with 2-4 ft seas.

For the forecast, fresh to strong E winds over the central
Caribbean will prevail through the end of the week. These winds will
reach as far north as Hispaniola adjacent waters. Fresh NE winds
are expected in the Windward Passage through Thu night. Fresh to
strong winds are forecast to pulse in the Gulf of Honduras tonight
and Thu night with seas building to 6-7 ft.

Under the influence of this trade wind surge propagating across
the Caribbean, conditions appear fairly favorable for heavy
rainfall amounts over southern Central America over the next few
days. The onset of the activity is expected late tonight, and
will likely peak Thu through Sat. In fact, the GFS model suggests
abundant tropical moisture in a NE winds flow from Nicaragua to
Panama and western Colombia today.

...ATLANTIC OCEAN...

A pair of tropical waves are between the west coast of Africa and
the Lesser Antilles. Please refer to the section above for
details.

A 1025 mb high pressure located E of Bermuda near 33N53W extends
a ridge across the Bahamas and Florida into the eastern gulf of
Mexico. Scattered showers are noted E of Florida and N of the NW
Bahamas ahead of a frontal boundary that crosses the SE of United
States. Another high pressure center is located just N of the
Madeira Islands. Fresh to strong northerly winds are noted per
scatterometer data near the coast of Morocco where seas are in the
5-7 ft range. Moderate to fresh N to NE winds are seen across the
Canary islands, and from 20N-30N E of of 30N. Seas are generally
in the 5-7 ft range within these winds. Similar wave heights are
also noted between 50W and the Lesser Antilles.

For the forecast W of 65W, high pressure will be in control of
the weather pattern across the region. Fresh to strong easterly
winds will pulse just off north of Hispaniola, including the
approach to the Windward passage in the late afternoon and
evening hours for the next several days.

$$
ERA
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