[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121806
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
206 PM EDT Thu Sep 12 2019

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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

A surface trough extends from the Atlantic Ocean, about 220 nm to
the N of the SE Bahamas, to SE Cuba with a 1008 mb low pressure
centered near 22N74W. Scattered moderate isolated strong
convection extends out 180 to 200 nm northeast of the low
pressure. Scattered moderate convection is noted from 22N-28N
between 64W- 67W, and scattered showers in the northern Bahamas
and Florida Straits. This area of disturbed weather is gradually
becoming better organized while surface pressure are falling in
the area. Conditions are becoming favorable for a tropical
depression or a tropical storm to form within the next day or so
as the system moves toward the northwest through the northwestern
Bahamas and toward the Florida Peninsula at 5 to 10 mph. If this
development trend continues Potential Tropical Cyclone advisories
will likely be initiated later today. This disturbance will bring
heavy rainfall and gusty winds across portions of the Bahamas
through Friday, especially in portions of the northwestern Bahamas
affected by Hurricane Dorian. An Air Force Reserve reconnaissance
aircraft is scheduled to investigate the system this afternoon,
if necessary. The chance of tropical cyclone formation during the
next 48 hours is high.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 30W, from 19N southward,
moving west at 10 to 15 knots. Scattered moderate isolated strong
convection is seen from 12N-31N between 29W-33W and near the
monsoon trough south of 09N. Conditions appear conducive for
development, and a tropical depression could form early next week
while the system moves westward over the tropical Atlantic.

An Atlantic Ocean tropical wave is along 40W, from 18N southward,
moving W 10 to 15 knots. Scattered showers are in the vicinity of
the wave axis.

An Atlantic Ocean tropical wave is along 55W, from 19N southward,
moving W 10 knots. Scattered moderate isolated strong convection are
from 13N to 15N between 52W and 57W. This wave is forecast to
move westward, toward unfavorable upper level winds, and tropical
cyclone formation is not anticipated.

A Caribbean Sea tropical wave is along 77W, from 19N southward,
moving W 15 knots. Numerous moderate to strong convection is noted
mainly along the monsoon trough from the coast of Colombia and
Panama extending north to 10N. No significant convection is noted
north of 10N. GOES 16 Dust Imagery shows plenty of SAL in the
vicinity of the wave axis extending from W Haiti west to Jamaica.

A western Caribbean Sea tropical wave is along 87W, from 17N
southward, moving W 10 knots. The wave passes through Honduras
and Nicaragua. Scattered moderate convection is in the Gulf of
Honduras from 16N-20N west of 84W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Guinea-Bissau near 10N15W, to
08N35W, to 13N56W. Scattered moderate convection extends 150 to
180 nm in the vicinity of the monsoon trough.

GULF OF MEXICO...

Broad surface anticyclonic wind flow spans the Gulf of Mexico. A
surface ridge extends from the western Atlantic from a 1022 mb
high pressure center into the eastern corner of the Gulf of Mexico.
ASCAT indicates moderate to fresh northeast winds across the east
a few isolated showers near 27N89W. In the western Gulf, a surface
trough extends from 25N97W to 18N93W. Scattered moderate isolated
strong convection is from 18N-24N and west of 93W-97W.

High pressure N of the basin will support moderate to fresh NE to
E winds into the weekend. A trough of low pressure currently over
the Bahamas is expected to move NW toward the Florida peninsula
through the end of the week, likely organizing into a tropical
cyclone. This feature will likely to move into the far eastern
Gulf of Mexico this weekend into early next week, accompanied by
widespread showers, thunderstorms, gusty winds, and building seas.

CARIBBEAN SEA...

In the upper levels, an anticyclonic flow extends from the Gulf
into the western Caribbean Sea. Precipitable water imagery shows
drier air in the region limiting the convection across the central
and eastern Caribbean. Scattered showers are in the NW Caribbean
sea near the tropical wave along 87W. Scattered moderate isolated
strong convection is noted near Colombia across Panama into Costa
Rica, south of 11N between 75W- 83W associated to the monsoon
trough in the area.

High pressure N of the region will maintain moderate trades, that
will at times pulse to fresh to strong in the south central
Caribbean. A tropical wave will cross from the central Caribbean
into the western Caribbean Fri morning, then exit into Central
America Sun. Another tropical wave will enter the tropical N
Atlantic and eastern Caribbean Fri night. A third and stronger
tropical wave will approach the tropical N Atlantic and eastern
Caribbean over the weekend into early next week, expected to bring
widespread showers and thunderstorms, gusty winds and building
seas.

ATLANTIC OCEAN...

An upper level trough extends from 31N52W southward to 23N52W. A
surface trough associated to the upper trough is noted from
32N48W to 21N54W. Scattered showers and thunderstorms are
developing in the vicinity of the trough and extend 220 nm east
and 150 nm west of the trough axis. Further east, broad high
pressure prevails across the region with a 1033 mb high pressure
north of the area.

A trough of low pressure over the SE Bahamas will track slowly WNW
through the remainder of the week. This trough is expected to
organize into a low pressure center over the next day or so, and a
tropical cyclone is likely to form by Saturday. This system will
bring widespread showers, thunderstorms, gusty winds, and
building seas to the Bahamas, and may reach the Florida peninsula
late Friday. A strong tropical wave may approach the waters S of
22N early next week.

$$
Torres
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