[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271802
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Jul 27 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
1705 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 stretches across the central Gulf of Mexico, from
28N85W to 23N93W. Scattered moderate convection within 100 nm on
either side of the trough. Recent scatterometer satellite data and
surface observations show light breezes across the basin, turning
cyclonically around the trough. Seas are 1-2 ft.

For the forecast, the scattered showers and isolated
thunderstorms will persist on either side of the trough axis
through tonight as it drifts westward. Atlantic high pressure will
begin to build westward into the Gulf region Wed and Thu with a
ridge persisting along 27N into Sat.

CARIBBEAN SEA...

The monsoon trough stretches from the SE Caribbean to eastern
Panama and into the Pacific. It is enhancing the development of
showers and isolated thunderstorms within 70 nm of the coasts of
SE Nicaragua, Costa Rica and northern Panama. Elsewhere, fair
weather prevails across the basin. Scatterometer satellite data
indicate that gentle to moderate trades dominate the central and
eastern Caribbean, while gentle winds are found in the northwest
Caribbean. Seas are 2-4 ft across the basin.

For the forecast, gentle to moderate trade winds are expected
across the basin through early Wed. 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 Wed 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...

A large 1031 mb high pressure system is positioned near the
Azores, resulting in mostly fair weather with gentle to moderate
winds. An exception is in the lee of a surface trough along 59W,
extending from 18N to 24N, where recent scatterometer satellite
data shows moderate to fresh breezes. Seas in the central and
western Atlantic are 4 to 6 ft. Elsewhere, fresh to strong winds
are found surrounding the Canary Islands and off the coast of
Morocco, resulting in seas 5 to 7 ft.

For the forecast, the Atlantic ridge will continue to dominate
the forecast area. An area of showers and thunderstorms is over
the NE waters, and will continue to move northward. A broad
inverted trough along 60W will move quickly westward and across
the SE waters through tonight, then north of the Greater Antilles
and across the southern Bahamas Wed through Thu.

$$
DELGADO/MORA
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