[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302320
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Sep 30 2020

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...Special Features

A tropical wave located over the west-central Caribbean Sea near
79W is moving west around 10-15 kt. Scattered moderate to strong
convection is noted from 11N-17N between 73W-83W. This system is
expected to continue moving westward over the next couple of
days and produce a broad area of low pressure over the western
Caribbean Sea by Thursday night or Friday. Environmental
conditions are forecast to be conducive for some development
thereafter, and a tropical depression could form over the weekend
while the system moves slowly west- northwestward over the
northwestern Caribbean Sea. There is a medium chance of
development in the next 5 days.

...TROPICAL WAVES...

A tropical wave extends its axis along 30W southward from 15N,
moving west at 10-15 kt. Scattered moderate convection is noted
from 08N- 13N between 27W-31W.

A tropical wave axis is along 55W southward from 17N, moving west
at 10-15 kt. Scattered moderate convection prevails along and
east of the wave's axis from 09N-17N between 52W-60W.

A tropical wave axis is along 70W southward from 20N, moving west
at 10-15 kt. Scattered moderate convection is noted from 12N-19N
between 67W- 71W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
11N15W to 10N24W to 08N38W. The ITCZ continues from 08N38W to
10N50W. Outside of the convection associated with the tropical
waves, an area of scattered moderate to isolated strong convection
is moving off the coast of Africa from 07N-15N E of 20W. Scattered
moderate convection is noted from 07N-10N between 34W-37W and
along the ITCZ from 06N-09N between 40W-50W.

Gulf of Mexico...

At 2100 UTC, a stationary front draped across the southern Gulf
and eastern Bay of Campeche, extending off the SW Florida coast
near 26N81W to the northern Yucatan near 21N90W to the southern
coast of Mexico near 19N92W. Scattered moderate convection is
noted within 50 nm of the front. Behind the frontal boundary,
ridging from a 1021 mb high pressure near 31N91W is building
across the NW and central Gulf and bringing dry, tranquil
conditions with it. Light to gentle winds and seas 4-6 are noted
in the northern Gulf. Fresh to strong N to NE winds are behind the
front in the eastern Gulf with seas up to 8 ft. Fresh to strong N
winds are in the western Bay of Campeche with seas up to 12 ft.

The stationary front will support strong to near gale force N
winds in the Bay of Campeche through tonight and moderate to fresh
NNE winds in the SE and SW basin through Thu. Moderate to fresh
winds in these portions of the basin will prevail thereafter as
surface ridging in the basin strengthen and an area of low pressure
develops over the far NW Caribbean. These winds may reach near
gale force speeds Thu night through Mon along with building seas.

CARIBBEAN SEA...

Please refer to the Special Features Tropical Waves section above
for details on the tropical waves.

The monsoon trough extends across the SW Caribbean from 12N76W to
10N83W. Scattered moderate convection is from 09N-14N between
74W-84W. Scattered moderate convection is also moving across the
Lesser Antilles. Diurnally driven convection is seen across the
Greater Antilles with some of the activity moving into adjacent
waters. Light to gentle winds are noted in the NW Caribbean with
fresh winds in the eastern Caribbean with seas 3-6 ft. Fresh to
strong easterly winds are noted in the central Caribbean with seas
up to 9 ft.

Moderate to fresh winds are expected over the central and eastern
Caribbean through Sat, and will decrease to gentle to moderate
for the remaining period. A tropical wave located over the western
Caribbean Sea is expected to move westward over the next couple
of days and interact with the remnants of a frontal system,
producing a broad area of low pressure over the far western
Caribbean Sea by Thursday night or Friday. Environmental
conditions are forecast to be conducive for some development
thereafter, and a tropical depression could form over the weekend.

ATLANTIC OCEAN...

Refer to the section above for details on the tropical waves
moving across the tropical Atlantic.

Surface ridging prevails across the basin, anchored by a 1036 mb
high is centered over the central Atlantic near 41N43W. A surface
trough is seen in the latest ASCAT pass from 30N45W to 25N38W and
a second trough further east extending south from a low pressure
near 32N31W to 25N29W.

A stationary front extends off the Florida coast in the SW
Atlantic from 30N75W to the SE Florida coast near 26N80W.
Scattered moderate convection is within 60 nm of the front with an
area of scattered moderate to isolated strong convection from
25N-31N between 74W-76W. Fresh N to NW winds are behind the front
with moderate S to SE winds ahead of the front. A surface trough
is analyzed in the central Atlantic from 31N47W to 25N40W. A
second trough farther east extends along a 1019 mb low near 32N32W
from 33N33W to 28N30W. Surface ridging extends across the rest of
the basin anchored by a 1036 mb high in the north- central
Atlantic. Gentle to moderate winds prevail across most of the
basin. Fresh easterly winds are noted north of Puerto Rico.

Moderate SSE winds ahead of a stationary front will prevail to
the E of the Bahamas through Thu as the front dissipates. A
tropical wave will move across the eastern and central Caribbean
Thu through Sun and will support moderate to fresh winds over the
SE offshore waters, increasing to strong N of Hispaniola at
night.

$$
AReinhart
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