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Atlantic Tropical Weather Discussion

AXNT20 KNHC 170553

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
153 AM EDT Tue Sep 17 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 0000 UTC surface analysis and satellite imagery through 
0520 UTC.


Hurricane Humberto is centered near 30.3N 75.1W at 17/0300 UTC or
540 nm W of Bermuda moving ENE at 7 kt. Estimated minimum central
pressure is 966 mb. Maximum sustained wind speed is 80 kt with 
gusts to 100 kt. Numerous strong convection is from 29N- 33N 
between 73W-77W. Scattered moderate convection is seen stretching
down to the Bahamas, from 24N-34N between 70W-73W. Humberto is
expected to gradually increase in forward speed through early 
Thursday. On the forecast track, the center of Humberto is 
expected to approach Bermuda Wednesday night. Some strengthening 
is forecast during the next 48 hours and Humberto is forecast to 
become a major hurricane by Tuesday night or Wednesday morning.
Please read the latest NHC forecast/advisory under AWIPS/WMO 
headers MIATCMAT4/WTNT24 KNHC, or at the website 
for more details.

A 1009 mb surface low is centered near 12N43W, about 1200 miles
east of the Lesser Antilles. A tropical wave extends from 02N-18 
along the low. Scattered moderate to isolated strong convection is
from 10N- 14N between 40W-46W. Environmental conditions are expected 
to be conducive for the formation of a tropical depression during
the next day or so while the system moves slowly northwestward to
west-northwestward. There is a high chance of tropical cyclone 
formation within the next 48 hours.


An eastern Atlantic tropical wave with axis along 32W S of 18N, moving
W at 00 kt. The wave shows up well in model diagnostics and TPW 
imagery. Scattered moderate convection is noted from 13N-16N
between 29W-33W in addition to 04N-06N between 28W-34W.

See section above for information on the tropical wave along 43W.

An eastern Caribbean tropical wave with axis along 65W S of 19N, 
moving W at 10 kt. This wave is well depicted in model guidance 
and TPW imagery. Scattered moderate convection is seen from 12N-
18N between 62W-68W.

A central Caribbean tropical wave with axis along 74W S of 19N, 
moving W at 15 kt. This wave is well depicted in TPW imagery. 
Scattered moderate convection is noted over the northern portion 
of the wave, affecting southwestern Hispaniola and adjacent 


The monsoon trough extends from the coast of Mauritania near 18N16W
to 12N27W to the low near 12N43W to 09N51W. The ITCZ continues 
from 09N51W to the coast of Guyana near 08N59W. Aside from the 
convection already discussed in the Tropical Waves section above, 
scattered showers and thunderstorms are in the vicinity of the 
monsoon trough and the eastern portion of the ITCZ between 19W-
53W. Scattered thunderstorms are also moving off the eastern coast
of Africa from 06N-10N and E of 15W.


A 1010 mb low is located in the NW Gulf of Mexico near 27N95W 
with a trough extending along the low from 26N96W to 29N93W. 
Scattered showers and thunderstorms are noted near the low from 
25N-30N between 92W-97W. Some slow development of this system is 
possible before it moves inland along the northwestern Gulf coast 
Tuesday night. Regardless of development, this system is expected 
to produce locally heavy rainfall and possible flash flooding 
along portions of the central and upper Texas coastal areas later 
this week. This system has a low chance of development in the 
next 48 hours. 

Numerous strong convection is seen moving off the Yucatan into the
eastern Bay of Campeche, from 19N-22N and E of 92W. Otherwise, 
the eastern Gulf of Mexico remains fair under upper level ridging.
Latest scatterometer data depicts light winds across the basin. 

Weak high pressure will build into the north central Gulf of 
Mexico through mid week. The high pressure will dissipate later in
the week, in advance of a weak cold front that is forecast to 
move across the eastern Gulf of Mexico. 


Refer to the Tropical Waves section above for details on the two
tropical waves currently over the Caribbean.

Relatively dry air covers the central and west Caribbean. The 
exception is along the eastern Pacific monsoon trough where
scattered thunderstorms are seen along 10N between 75W-79W.
Scattered thunderstorms are also moving south of Cuba toward the
Grand Cayman Islands. The latest ASCAT pass depicts light to 
moderate trades across the basin. Moderate to fresh winds are
noted in the Gulf of Honduras and the Gulf of Venezuela. 

Moderate to fresh trade winds will dominate much of the basin. 
Long period northerly swell will starting pushing through the 
Atlantic Ocean passages by Tuesday. A tropical wave entering the 
central Caribbean Sea will move through the western Caribbean Sea 
by Wed. Scattered thunderstorms and gusty winds accompany a second
tropical wave that is in the eastern Caribbean. The second 
tropical wave will move across the central Caribbean Sea by
Wednesday, and into the western Caribbean Sea late Thursday to 
Friday. A low pressure center developing east of the area, will 
move toward the Atlantic Ocean offshore waters of the Leeward 
Islands by late Thursday and Friday, possibly as a tropical 


Refer to the sections above for details on Hurricane Humberto and
the tropical waves moving across the basin.

A 1021 mb surface high is over the central Atlantic near 32N53W.
Scattered thunderstorms are also seen in the central Atlantic 
from 24N-30N between 56W-61W. To the east, a cold front enters the
discussion area near 31N32W to 25N41W, then stalls from 25N41W to
25N52W. Scattered showers are noted along the front. 

Northerly swell will follow across the open waters in the wake of