[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121741
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Jun 12 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
1700 UTC.

...TROPICAL WAVES...

A new tropical wave is added to the 12Z surface map along 21W
based on satellite imagery and tropical wave diagnostic. Scattered
moderate convection is from 6N to 12N between 20W and 25W.

The axis of another tropical wave is near 32W from 15N southward,
moving W at 15 to 20 kt. Scattered moderate and isolated strong
convection is noted from 01N to 09N between 25W and 36W.

The axis of a third tropical wave is near 51W from 15N southward,
moving W at 15 to 20 kt. Scattered moderate convection is noted
from 09N to 12N between 47W and 54W. This tropical wave is
forecasted to reach the Windward Islands near late Sunday,
increasing the likelihood of showers and isolated thunderstorms.

The axis of a fourth tropical wave is near 76W from 18N
southward, moving W at 10 to 15 kt. Scattered moderate and
isolated strong convection is near the southern end of the wave
affecting parts of Colombia and eastern Panama.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Senegal and Guinea-
Bissau near 12N16W and continues through 07N27W to end near
03N38W. The ITCZ then continues from 04N38W to end near 05N49W
northeast of French Guyana. No additional convection is noted
other than described in the tropical wave section above.

GULF OF MEXICO...

An area of showers and thunderstorms remained over the
southwestern Gulf of Mexico, affecting mainly the waters from 20N
to 22N between 91W to 96W. Winds and seas could be higher near
thunderstorms. Slow development of this system is possible over
the next several days as it moves slowly and erratically, and a
tropical depression could form in this area by the middle of next
week. Due to the slow motion, regardless of development, heavy
rainfall is possible over portions of Central America and southern
Mexico. Please consult products from your local meteorological
service for more information.

This area is enhanced by divergent flow east of an upper-level
trough over central Mexico, with increased convergence associated
with a surface trough over the Yucatan and E Gulf from 20N90W to
26N83W. Light to gentle winds are in the northern Gulf while
gentle to moderate E-SE winds are over the southern Gulf. Earlier
scatterometer data showed an area of fresh to strong winds in the
area of deep convection in the Bay of Campeche. Seas are 4-6 ft
throughout the basin.

For the forecast, weak high pressure ridging will remain over the
central Gulf of Mexico through early next week supporting mainly
gentle to moderate anticyclonic winds across the basin. A trough
of low pressure is expected to form by early next week over the
Bay of Campeche in the southwestern Gulf of Mexico. Some slow
development is possible thereafter as this system drifts
northward.

CARIBBEAN SEA...

Recent scatterometer data show fresh to strong winds across the
central Caribbean Sea, and gentle to moderate winds for the rest
of the basin. Moderate to fresh E-SE winds are in the Gulf of
Honduras. Light to gentle winds are in the lee of Cuba and also
south of 11N. Seas are 5 to 7 ft in the S central Caribbean, and
3-5 ft elsewhere except 3 ft or less in the lee of Cuba and south
of 11N.

Scattered showers and isolated thunderstorms are seen over the
Gulf of Honduras, triggered by convergent southeasterly winds and
enhanced by divergent flow aloft. Mid to upper-level cloudiness
associated with an upper-level trough entering into the Caribbean
Sea to eastern Dominican Republic is seen over eastern Caribbean
and the Leeward Islands.

For the forecast, a ridge of high pressure along 28N combined
with lower pressure over Central America and Colombia will support
fresh to strong trades over the S central Caribbean and Gulf of
Honduras into Thu. Moderate to fresh trades will prevail
elsewhere, except light to gentle south of 11N. A tropical wave
will move into the E Caribbean Mon.

ATLANTIC OCEAN...

Scattered showers and isolated thunderstorms are noted from just
north of the northwest Bahamas southwestward to southern Florida
from 24N to 28N between 77W and 83W. Otherwise, high pressure
ridging dominates the basin anchored by a 1027 mb high center over
the Azores at 38N27W, extending west-southwest through 29N55W to
the Bahamas. Fresh to strong northeast winds are found south of
the high between 20N and 30N including the Canary Islands, with
seas in the 5 to 7 ft range. Light to gentle anticyclonic winds
are noted under the ridge, with seas 3 to 5 ft range. Moderate to
locally fresh S-SW flow is present off the coast of northern
Florida.

A large area of Sahara dust covers the tropical Atlantic westward
to near the Windward Islands. Both the GOES Geocolor imagery and
Sahara Dust imagery from CIMSS indicate this feature.

For the forecast west of 65W, a ridge of high pressure along 28N
will sink southward this weekend. Winds will increase up to a
fresh breeze north of 28N through the weekend as a cold front
moves by north of the area. Winds may again strengthen to fresh
north of 28N on Tue and Wed as another cold front moves by north
of the area.

$$

GR/PC
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