[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291753
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Jun 29 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...

An Atlantic tropical wave is repositioned to be along 33W from
15N southward and moving W at 15 to 20 kt. Scattered moderate
convection is seen from the Equator to 11N between 27W and 36W.

Another Atlantic tropical wave is along 49W from 17N southward. It
is roughly 650 miles E of the Windward Islands and moving W near
20 kt. A broad 1009 mb low pressure system is embedded within
this wave near 12N49W. Scattered moderate convection is noted
from 11N to 16N between 43W and 53W. Some slow development of this
disturbance is possible later this week and this weekend while the
system moves westward to west-northwestward near 15 kt, likely
reaching the Lesser Antilles by Wednesday night. Please read the
latest Tropical Weather Outlook at www.hurricanes.gov, for more
information.

A Caribbean tropical wave is near 67W from just south of Puerto
Rico southward, and moving westward at 10 to 15 kt. No
significant convection is occurring with this wave.

Another Caribbean tropical wave is near 88W from south of Cuba at
18N southward and moving W at 10 to 15 kt. Aided by divergent flow
related to an upper-level high just off the coast of Honduras at
15N82W, scattered showers and thunderstorms are occurring over
the western Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of Guinea-
Bissau near 12N16W to 08N29W to near 11N46W. Scattered moderate
convection is found 06N to 11N between 37W and 42W.

GULF OF MEXICO...

An upper-level trough runs WSW from a low pressure centered near
the Florida Panhandle across the northern Gulf to another low over
northern Mexico. Divergent flow south of these features is
coupling with convergent SE winds to trigger numerous showers and
thunderstorms across the western Gulf from 20N to 25N between 97W
and the Mexican coast. Scattered moderate convection is present
over the northeastern Gulf from 25N to 29N between 83W and 89W.
Moderate to fresh SE winds and seas of 3 to 5 ft prevail over the
western basin, while gentle to moderate SE winds and seas of 2 to
4 ft dominate the eastern Gulf.

For the forecast, a ridge will dominate the Gulf waters over the
next several days producing mainly moderate E to SE winds. Fresh E
to SE fresh winds are expected at night near the western Yucatan
Peninsula through Fri due to local effects induced by a thermal
trough.

CARIBBEAN SEA...

Refer to the Tropical Wave Section above for more detail
information on convection.

A dry trade-wind pattern persists across the central and eastern
Caribbean basin. Moderate to locally fresh trades and seas of 6
to 9 ft prevail across the central Caribbean. Gentle to moderate
trades and seas of 3 to 5 ft are seen for the rest of the basin.

For the forecast, building high pressure N of the Caribbean Sea
combined with the Colombian low will bring increasing winds and
seas across the basin, but particularly across the south-central
Caribbean. Some slow development of the tropical wave
approximately 650 nm east of the Lesser Antilles is possible
later this week and this weekend while the system moves westward
to west- northwestward at 15 to 20 kt, likely reaching the Lesser
Antilles by Wednesday night, and Puerto Rico on Thu. Increasing
winds and seas will be associated with the wave passage. Another
tropical wave is forecast to approach the Lesser Antilles on Fri.

ATLANTIC OCEAN...

A weakening stationary front is noted from 31N37W west-
southwestward to 28N54W, then turns northwestward to 29N58W.
Scattered clouds and showers are evident up to 150 nm along
either sides of this front. An upper-level trough extends W from a
low SE of Bermuda near 27N59W to near N Florida. Diffluent flow
S of these features is triggering scattered moderate convection E
of the Bahamas from 21N to 26N between 63W to 71W.

Elsewhere across the basin, weather N of 23N is being dominated
by high pressures centered NE of the Bahamas and to the N of the
Canary Islands. This is leading to mainly gentle winds and seas of
3 to 5 ft across this area. Moderate to fresh trades and seas of
6 to 8 ft exist between 23N and 10N from the Bahamas eastward to
the west coast of Africa. Gentle to moderate trades and seas of 6
to 8 ft are found elsewhere.

For the forecast W of 65W, the Atlantic ridge will build westward
and dominate the forecast waters the remainder of the week. Fresh
to strong winds winds are expected just N of Hispaniola Thu night
through Sat night due to the pressure gradient between the
Atlantic ridge and a couple of tropical wave passages over the
Caribbean Sea.

$$

EC/Chan
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