AXNT20 KNHC 111749 CCA

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
149 PM EDT Wed Sep 11 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
1730 UTC.


A sharp surface trough extends from 25.5N70W across the SE
Bahamas to 18N75.5W. Scattered to numerous moderate with
embedded isolated strong convection is seen from 20N-26N between
68W-75W. Scattered moderate convection also covers the area from
26N-30N between 61W-75W, enhanced by upper-level divergence. The
latest ASCAT pass shows widespread fresh to locally strong NE
winds between the surface trough and South Florida. The surface
trough will track slowly WNW through the end of the week,
reaching the Florida Peninsula and Florida Straits late Friday.
Conditions are forecast to become more favorable for development
by late this week, and a tropical depression could form near the
northwestern Bahamas or South Florida as early as Friday.
Further development is possible when the system is located over
the eastern Gulf of Mexico later in the weekend. The disturbance
is likely to produce periods of heavy rain and gusty winds
across the Bahamas through Friday, and across Florida during the
weekend. The disturbance has a medium chance of tropical cyclone
formation during the next 48 hours.


An eastern Atlantic Ocean tropical wave is along 23/24W, passing
through the Cabo Verde Islands from 20N southward. The tropical
wave is moving W around 10 kt. Scattered moderate convection is
seen within 150 nm of the wave axis from 12N-15N. Similar
convection is seen from 04N-08N within 270 nm E of the wave axis.
This wave is forecast to move westward quickly during the next
several days. Some slow development is possible over the weekend
or early next week when the system is moving over the tropical

A tropical wave has been added to the analysis along 37W from 19N
southward, moving W at 10-15 kt. Scattered moderate showers are
from 05N-18N between 28W-40W.

An Atlantic Ocean tropical wave is along 50/51W from 07N-19N,
moving W around 10 kt. A 1010 mb low pressure center is along the
wave near 14N. Scattered moderate rainshowers are from 10N-16N
between 45W-55W. This system is forecast to move westward toward
unfavorable upper-level winds for tropical cyclone formation.

A Caribbean Sea tropical wave is along 70/71W from 16N southward,
moving W around 15 kt. Isolated showers are near and E of the wave
axis S of 15N. Scattered showers are inland over NW Venezuela.

A western Caribbean Sea tropical wave is along 84/85W from 17N
southward, moving W around 10 kt. Scattered moderate convection is
S of 12N near and E of the wave axis. Isolated showers are north
of 12N.


The monsoon trough passes through coastal sections of The Gambia
near 13N17W to 10N24W to 10N31W to 12N42W. The ITCZ extends from
12N42W to 13N48W. Aside from the convection mentioned in the
Tropical Waves section, scattered moderate convection is seen
within 90 nm of the W coast of Africa from 05N-11N.


Upper-level cyclonic wind flow covers east Texas, NE Mexico and
the western Gulf of Mexico, from 25N-32N between 93W-99W. A
surface trough is over the western Bay of Campeche from 24N97.5W
to 21N96.5W to 19N95W. Strong upper-level divergence and upper-
level diffluence cover the SW Gulf of Mexico. As a result,
scattered to numerous moderate with embedded isolated strong
convection is over the SW Gulf of Mexico from 18N-27N between
91W-98W. Isolated showers and tstorms are elsewhere W of 86W.
Another upper-level low is near northern Florida near 29N83W. This
upper-low currently has drier air with it and little in the way
of any shower activity. At the surface, a 1025 mb high over NE
Georgia extends a ridge into the NE Gulf of Mexico. The latest
ASCAT pass shows that moderate wind speeds cover most of the Gulf,
except for fresh NE winds in the Florida Straits and far SE Gulf.

High pressure centered north of the basin will support moderate to
fresh NE to E winds into the weekend. Surface troughing in the
western Bay of Campeche is expected to persist through Fri,
leading to scattered showers and tstorms. A trough currently over
the SE Bahamas will move W across South Florida and the Florida
Straits Fri or early Sat, and into the eastern Gulf of Mexico
this weekend, where a tropical depression could form. Regardless
of whether this system is a tropical cyclone when it reaches the
eastern Gulf of Mexico, the system is likely to be accompanied
by widespread showers, thunderstorms, and gusty winds.


A surface trough extends from 25.5N70W to 18N75.5W. Isolated to
scattered moderate convection is over water in between Jamaica and
the Windward Passage. Scattered showers and isolated tstorms from
18N-21N between 81W-86W may be related to the northern end of the
tropical wave that is along 84W. In the far SW Caribbean,
scattered showers and tstorms are seen south of a line from
10N76W to 12.5N83.5W due to the combination of the East Pacific
monsoon trough and the tropical wave along 84W.

Mid-level and upper-level anticyclonic flow covers the eastern
Caribbean, leading to generally dry conditions, except for a few
light showers south of 15N near and to the east of the tropical
wave along 70W.

High pressure centered N of the region will maintain moderate
trades, that will at times pulse to fresh to strong in the S
central Caribbean. The tropical wave along 70W will reach the
western Caribbean Fri. The tropical wave along 51W will reach the
NE Caribbean Fri night, bringing increased showers and tstorms. A
strong tropical wave, currently located along 24W, will approach
the Lesser Antilles Sun, moving into the eastern Caribbean Mon.
Gusty winds and squalls will accompany this tropical wave.


For information on the tropical disturbance currently over the
Bahamas, see the Special Features section above.

An upper-level low is near northern Florida near 29N83W and is
moving southwestward. Another upper-level low near 33N66W is
moving southward. This upper-low is helping to enhance
convection northeast of the Bahamas.

Farther E, a surface trough from 27N49W to 22N55W is producing
scattered moderate convection from 21N-26N between 46W-57W. A
couple of smaller surface troughs are analyzed to the north of the
northern end of that trough. Scattered showers and isolated
tstorms are seen from 27N-32N between 43W-52W. A large upper-level
low is centered near 34N33W, and a surface trough is analyzed from
31N32W to 27N37W. Scattered showers and tstorms are seen N of 30N
between 29W-36W.

In the far E Atlantic, northerly strong to near gale force winds
are expected offshore of Morocco and near the Canary Islands
through Thu.