[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272347
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Jul 28 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
2350 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave has been introduced near the coast of
Africa along axis 17W, south of 18N, based on satellite imagery,
tropical wave diagnostic and the Hovmoller diagram. Scattered
moderate convection in noted from 07N to 13N and between the
coast of Africa to 19W. The northern portion of the wave is
surrounded by dry and dusty Saharan Air Layer, resulting in no
convection.

Another Atlantic tropical wave is along 33W, south of 20N, and
moving W near 15 kt. A broad area of Saharan Air accompanies this
wave, which is hindering convection north of 10N at this time.
Associated scattered moderate convection is confined to near the
monsoon trough, from 05N to 10N and between 28W and 36W.

A Caribbean tropical wave is along 67W, south of 15N, and moving
W at 10-15 kt. A dry and stable airmass surrounds this wave,
resulting in no convection over the eastern Caribbean. However,
the wave is enhancing the development of showers and thunderstorms
over southern Venezuela and eastern Colombia.

Another Caribbean tropical wave is along 80W, south of 19N, and
moving W at 10-15 kt. Upper-level divergence is supporting
scattered showers and isolated tstms from 13N to 19N and between
78W to 82W.

A third Caribbean tropical wave is along 87W, extending from the
Gulf of Honduras, across Honduras and western Nicaragua, to the
eastern Pacific. The wave extends south of 20N and it is moving W
at 10 kt. No significant convection is associated with this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Guinea-Bissau near 12N16W to
07N37W. The ITCZ continues from 07N38W to 09N54W. An area of weak
convection is noted within 100 nm of the ITCZ between 45W to 51W.

GULF OF MEXICO...

A surface trough remains over the central Gulf generating
scattered showers and isolated thunderstorms while middle to upper
level divergence support similar shower activity over the NE
basin. A weak surface ridge cover the remainder gulf supporting
light to gentle variable winds, except along the Yucatan adjacent
waters where the passage of a tropical wave is supporting moderate
to locally fresh NE to E winds.

The trough will drift toward the NW Gulf on Wed. In its wake, the
Atlantic high pressure will begin to build westward into the Gulf
waters Wed and Thu, with a ridge persisting along 27N into Sat.

CARIBBEAN SEA...

Three tropical waves are moving across the basin with the most
active being the one with axis along 80W, which is generating
heavy showers and tstms over the NW basin, including Jamaica and
adjacent waters. Similar shower acivity is observed along Cuba
being supported by divergent flow aloft. In the SW basin, the
eastern extension of the monsoon trough generates heavy showers
along NW Colombia adjacent waters and isolated showers in Central
America offshore waters. Otherwise, with a weak pressure
gradient across the region, mainly moderate trade winds prevail
with locally fresh winds in the south-central basin and vicinity
of the tropical waves.

Gentle to moderate trade winds are expected across the basin
through Thu. The exception will be moderate to locally fresh winds
near the coast of Colombia, in the Gulf of Venezuela and Gulf of
Honduras. Winds will increase across the E and central Caribbean
Thu night into Fri as the Atlantic ridge builds westward in the
wake of a trough moving westward across the Atlc waters north of
the Greater Antilles.

ATLANTIC OCEAN...

The Bermuda-Azores high dominates the forecast region and supports
mainly light to gentle variable winds over the subtropical SW and
central regions of the basin. Over the subtropical E Atlc, latest
scatterometer data show fresh NE winds off the coast of W Africa,
including the Canary Islands where seas are 5-6 ft. A col of low
pressure in the middle levels is supporting an area of showers N
of 27N between 59W and 71W.

Otherwise, expect fresh to locally strong easterly winds at night
just off N of Hispaniola, including approaches to the Windward
Passage most of the forecast period.

$$
Ramos
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