[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131801
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Jun 13 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
1800 UTC.

...TROPICAL WAVES...

A new tropical wave might be added along 13W and inland over west
Africa on the 18Z surface analysis. Latest satellite imagery
reveals scattered to numerous moderate and isolated strong
convection near the west coast of Africa from 03N to 13N between
06W and 18W.

The axis of a tropical wave is near 30W and from 17N southward,
moving W at 10 to 15 kt. Isolated moderate convection is noted
near the southern part of the wave within 70 miles of 07N25W.

The axis another tropical wave is near 39W from 15N southward,
moving W at 10 to 15 kt. Scattered moderate and isolated strong
convection is noted near the southern end of the wave from 02N to
07N between 31W and 41W.

The axis of a third tropical wave is near 56W from 15N southward,
moving W at 5 to 10 kt. Scattered moderate convection is noted
north of Guyana from 08N to 10N between 52W and 58W. This
tropical wave is forecasted to reach the Windward Islands this
evening, increasing the likelihood of showers and thunderstorms
there.

The axis of a fourth tropical wave is along 80W from 18N
southward, moving W at near 5 kt. Isolated showers are noted
across the Colombian Basin along both sides of the wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Africa near the
border of Guinea Bissau at 11N14W and continues through southwest
of the Cap Verde Islands near 10N28W to end north of Brazil at
06N44W. The ITCZ then continues from 06N44W westward to end near
north of French Guyana at 08N54W. Aside from the convection
described in the tropical waves section above, there is no other
major convection.

GULF OF MEXICO...

A broad low pressure area of 1010 mb is centered over the Bay of
Campeche near 20N95W. A surface trough extends northwestward from
17N91W through the low to 23N96W. Scattered moderate and isolated
strong convection is noted from 18N to 23N between 90W and 97W.
The overall system has become somewhat better organized since
yesterday. Slow development is possible during the next few days
while the system meanders near the coast of Mexico, and a tropical
depression could form late in the week while the system begins to
move slowly northward. Regardless of development, heavy rainfall
is possible over portions of Central America and southern Mexico
during the next several days. Please consult products from your
local meteorological service for more information. Currently the
Tropical Weather Outlook gives this disturbance a medium chance of
tropical cyclone development through 5 days.

A 1015 mb high is centered near 28N94W with a ridge axis
extending westward to the central Texas coast and also eastward
through southern Florida. A surface trough curves northeastward
from the NE Gulf at 25N85W across central Florida to just east of
Georgia coast at 31N79W. Aided by divergent flow aloft, scattered
moderate convection is seen south of New Orleans within 50 miles
of 28N88W, and from west and central Cuba northeastward to the
Bahamas. Light to gentle anticyclonic winds are noted over the NW
Gulf north of 27N, with gentle to moderate westerly winds across E
Gulf. Moderate E to SE winds are present south of 27N, including
the Gulf of Campeche. Seas are 1 to 3 ft are across the basin,
except higher in and near any convection.

For the forecast, weak high pressure ridging will remain over the
central Gulf of Mexico through early week supporting mainly
gentle to moderate anticyclonic winds across the basin.

CARIBBEAN SEA...

Latest scatterometer data showed fresh to occasional strong winds
in the S central Caribbean and north of Colombia with seas at 4 to
7 ft. Gentle to moderate trades prevail elsewhere with seas of 2
to 4 ft. Convergent southeasterly winds are coupling with upper-
level diffluence to trigger scattered showers and isolated
thunderstorms over the Gulf of Honduras extending northward to
the Yucatan Peninsula.

For the forecast, a ridge of high pressure north of the basin
combined with the Colombian low will support fresh to strong
trades over the S central Caribbean and Gulf of Honduras into Thu
night. Moderate to fresh trades will prevail elsewhere, except
light to gentle south of 11N. A tropical wave will move into the E
Caribbean late tonight and cross the central Caribbean during
midweek.

ATLANTIC OCEAN...

A surface trough curves northeastward from the NE Gulf at 25N85W
across central Florida to just east of Georgia coast at 31N79W.
Numerous showers and scattered thunderstorms are flaring up over
central Florida and westward into the Gulf of Mexico. Elsewhere,
high pressure ridging dominates the basin anchored by a 1030 mb
high center over the Azores near 38N28W, extending west-southwest
through 31N47W to the northeastern Caribbean and the southeast
Bahamas. Gentle to moderate winds are found under the ridge axis,
with moderate to fresh winds north of 27N and west of 60W, as well
as south of 20N and west of 40W, and east of 50W. An upper-level
low near 30N50W is triggering scattered showers and isolated
thunderstorms north of 23N between 42W and 51W. Tightening
pressure gradient between the Azores high and lower pressure over
northern Africa is producing fresh to strong northeast winds
south of 28N and east of 27W near and south of the Canary Islands
with seas at 6 to 8 ft. Seas are mainly 4 to 6 ft east of the
Bahamas across the open waters of the tropical Atlantic.

A large area of Sahara dust covers the tropical Atlantic westward
to eastern Caribbean. 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 today. Winds will fresh north of 28N through
the early part of the week as pair of cold fronts move by north of
the area, except locally strong Tue through Wed.

$$

GR/PC
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