[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150551
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
151 AM EDT Sun Sep 15 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
0530 UTC.

...SPECIAL FEATURES...

Tropical Storm Humberto is centered near 27.6N 77.3W at 15/0300
UTC, or 75 nm N of Great Abaco Island, moving NNW at 5 kt.
Estimated minimum central pressure is 1000 mb. Maximum sustained
wind speed is 50 kt with gusts to 60 kt. Numerous moderate to
scattered strong convection extends outward from the center 150 nm
NE quad, 210 nm SE quad and 105 nm NW quad, with no convection in
the SW quad. On the forecast track, the center of Humberto should
continue to move well offshore of the east coast of Florida
during the next day or so and then move away from the U.S.
Humberto is forecast to become a Hurricane by tonight. Please
read the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT4/WTNT24 KNHC, or at the website hurricanes.gov for more
details.

...TROPICAL WAVES...

A tropical wave has been added to the map in the eastern Atlantic
along 19W from 18N southward, moving W around 15 kt. The wave
shows up well in 700 mb trough diagnostics and TPW imagery.
Scattered moderate convection is from 12N-18N between 16W-23W.
Scattered showers are from 05N-12N between the wave axis and 25W.

A tropical wave with axis along 38W from 05N-15N, is moving W
around 15 kt. The wave is well depicted in satellite imagery and
TPW imagery. Scattered moderate convection is from 07N-12N between
35W-42W. Conditions are forecast to be conducive for gradual
development through the middle of next week and a tropical
depression could form while the system moves slowly westward or
west-northwestward.

A central Atlantic tropical wave with axis along 51W from 07N-
21N is moving W around 20 kt. This wave is well depicted in model
guidance and satellite imagery. Scattered showers are from 07N-
20N between 45W-56W.

A tropical wave is currently over the Lesser Antilles, with axis
extending from 20N59W to 06N62W, moving west around 10-15 kt.
Scattered moderate convection is over the Lesser Antilles from
13N-18N between 60W-64W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Guinea-Bissau near 12N16W to
08N42W. Aside from the convection already discussed in the
Tropical Waves section above, scattered showers are noted within
180 nm N and 150 nm S of the monsoon trough between 20W-42W.

GULF OF MEXICO...

The weather over the Gulf of Mexico is dominated by a large mid to
upper-level low that is centered over the central portion of the
basin near 25N91W. The GFS model analysis and 6-hr forecast
indicates that the low is closed from 250-500 mb, and there is a
sharp trough at 700 mb. There is a weak low-level trough too, but
the low-level trough is still more subtle at this time. Upper-
level diffluence and divergence on the east side of the upper-low
are enhancing scattered to numerous moderate convection from 24N-
29N and east of 92W. Scattered showers and isolated tstorms are
from 25N-29N between 92W-95W. Some slow development of this system
is possible during the next couple of days while it moves
westward over the western Gulf of Mexico. The system is forecast
to move inland along the northwestern Gulf coast by late Monday or
Tuesday, and further development is not expected after that time.
The latest ASCAT pass depicts fresh easterly winds across the
northern half of the basin north of 24N, while gentle winds
prevail south of 24N. Moderate to fresh east to northeast winds
are expected across the northern Gulf through Mon associated with
the area of low pressure.

CARIBBEAN SEA...

A tropical wave is currently producing scattered moderate showers
and thunderstorms over the Lesser Antilles. See the Tropical
Waves section for details.

Mid-level anti-cyclonic flow is over Cuba and Jamaica, and
relatively dry air covers the central Caribbean. A W-E surface
trough is over western Cuba with isolated to scattered showers
over Cuba. In the SW Caribbean, scattered moderate convection is
over E Nicaragua and over water within 60 nm east of the coast of
Nicaragua. Scattered showers are elsewhere southwest of a line
from 10N75W to 15N83W. Scattered showers and tstorms are seen over
the eastern Dominican Republic and over water from 15N-16.5N
between 70W-73W. The latest ASCAT pass depicts fresh to strong
trades in the south-central Caribbean.

Moderate to fresh trade winds will dominate much of the basin,
with fresh to strong winds in the south-central Caribbean through
today. A tropical wave moving across the eastern Caribbean today
will reach the central Caribbean on Monday. A second, stronger
tropical wave will approach Barbados late today, move across the
eastern Caribbean Mon, and into the central Caribbean through mid
week, bringing widespread showers and thunderstorms, gusty winds
and building seas. Northerly swell from a large, storm-force mid-
latitude low currently centered near 40N46W, will reach the
Atlantic passages into the Caribbean Sea late on Monday and
continuing into mid-week.

ATLANTIC OCEAN...

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

A surface trough over western Cuba is producing scattered showers
and isolated tstorms over central and western Cuba as well as the
Florida Straits. A mid to upper-level low near 26N57W is enhancing
scattered showers and isolated tstorms from 20N-30N between 54W-
64W. A cold front extends over the discussion area from 32N47W to
31N54W to 32N64W. Scattered showers are south of the front. A
surface trough extends from 30N43W to 25N51W. Scattered showers
and tstorms are mainly east of the trough axis from 25N-31N
between 38W-48W. The remainder of the eastern Atlantic is under
surface ridging.

Tropical Storm Humberto is near 27.6N 77.3W, 1000 mb, at 11 PM
EDT moving NNW at 5 kt. Maximum sustained winds are 50 kt with
gusts of 60 kt. Humberto is forecast to become a hurricane this
evening near 29N78W, move to near 31N72W by Tuesday evening as a
90 kt hurricane, to near 33N66W Wed evening and near 37N59W Thu
evening.

Northerly swell from a large, storm-force mid-latitude low
currently centered near 40N46W, will reach the Atlantic passages
into the Caribbean Sea late on Monday and continuing into mid-
week.

$$
Hagen
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