[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081030
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
630 AM EDT Sun Sep 8 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 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Dorian is centered near 48.5N 61.1W at
08/0900 UTC or 70 nm W of Cape St George Newfoundland moving NNE
at 23 kt. Estimated minimum central pressure is 960 mb. Maximum
sustained wind speed is 70 kt with gusts to 85 kt. Numerous
showers are moving across eastern Canada. Dorian will continue
moving generally NE for the next 24 hours. After that, a turn
toward the east-northeast is expected. On this track, Dorian will
be moving near or over western Newfoundland later today and then
enter the North Atlantic this evening. The post-tropical cyclone
is expected to weaken during the next couple of days, and it is
forecast to drop below hurricane strength by Sunday morning. See
the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT5/WTNT25 KNHC or the website hurricanes.gov for more
details.

Tropical Storm Gabrielle is centered near 32.7N 48.6W at 08/0900
UTC or 1100 nm W of the Azores moving NW at 11 kt. Estimated
minimum central pressure is 1000 mb. Maximum sustained wind
speed is 50 kt with gusts to 60 kt. Scattered moderate convection
is north and west of the center, from 27N-36N between 46W-54W.
The storm is forecast to turn northward over the central Atlantic
later today and then accelerate northeastward into the north
Atlantic Monday and Tuesday. Some strengthening is forecast
during the next couple of days. Gabrielle is forecast to become an
extratropical low and begin weakening on Tuesday. See latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC or
the website hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave near the coast of Africa is along 17W S of 20N,
moving W at around 10-15 kt. Scattered moderate convection is in
the vicinity of the wave axis from 08N-17N between 10W-20W.

An eastern Atlantic tropical wave extends its axis along 35W S of
20N, moving W at 10-15 kt. A 1011 mb surface low is embedded in
the wave environment centered near 15N35W. Scattered showers are
noted near the low from 14N-18N between 35W-39W. Gradual
development of this system is possible, and a tropical depression
could form by the middle of next week while the system moves
westward across the eastern and central tropical Atlantic Ocean.
The chance of tropical cyclone formation during the next 48 hours
with this system is low.

An Atlantic tropical wave extends its axis along 54W S of 15N,
moving W at 10-15 kt. Scattered showers are noted within 100 nm on
either side of the wave axis.

A west-central Caribbean tropical wave extends its axis along 74W
S of 20N, moving W at 15-20 kt. Scattered showers are noted along
the northern portion of the wave, mostly impacting Hispaniola and
adjacent waters.

A west-central Caribbean tropical wave extends its axis along 81W
S of 18N, moving W at 10 kt. Scattered showers are noted along
the southern portion of the wave, mostly impacting Central America
and the EPAC waters.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 16N17W
to the low pressure mentioned in the Tropical Waves section above
near 15N35W to 09N42W. The ITCZ begins near 09N42W to 08N53W.
Aside from the convection mentioned in the section above,
scattered moderate convection is noted within 75 nm on either side
of the ITCZ.

GULF OF MEXICO...

A surface trough stretches across the eastern Gulf from the west
coast of Florida near 25N84W to 24N90W. A few showers are along
the boundary. In the Bay of Campeche, another surface trough is
analyzed from 22N90W to 19N93W. Scattered moderate convection
and locally fresh winds are noted near this trough. High pressure
is building across the far western Gulf, anchored by a 1017 mb
high centered near 27N92W and a 1016 mb high centered near 28N87W.
Latest scatterometer data depicts light to gentle winds across
the basin.

The frontal trough across the eastern Gulf will dissipate through
tonight. Weak high pressure will persist across the Gulf through
next week, with mainly gentle to moderate winds expected, except
occasionally fresh near the Yucatan Peninsula.

CARIBBEAN SEA...

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

An upper-level low is meandering into the eastern Caribbean. This
is causing scattered showers to move across the Lesser Antilles.
Scattered moderate convection is also noted in the SW basin from
the monsoon trough, S of 10N between 73W-82W. Scattered moderate
convection is also noted in the Gulf of Honduras. Latest
scatterometer data depicts moderate trades in the central and
southeast Caribbean, with light to gentle trades elsewhere.

Weak high pressure ridging north of the area will be
be replaced by stronger high pressure that builds southward over
the western Atlantic and the U.S. eastern seaboard during the
early part of the upcoming week. An induced tighter gradient
between the high pressure and couple of tropical waves presently
moving through the central and western Caribbean will allow for
trades to increase in the south-central Caribbean beginning Mon,
then diminish late in the week. Elsewhere, mainly moderate trade
winds will continue through late in the week.

ATLANTIC OCEAN...

Refer to the sections above for details on Dorian, Gabrielle and
three tropical waves moving across the basin.

A 1017 mb surface high is near 28N68W. A surface trough extends
across the central Atlantic from 19N56W to 15N64W with scattered
showers and thunderstorms occurring along and north of the
trough. Surface ridging prevails across the eastern Atlantic.

A well defined low-level trough will move from E to
W across the area during the upcoming week accompanied by
scattered to numerous showers and thunderstorms. Otherwise,
relatively weak high pressure across the area will gradually
lift northward through through Thu.

$$

ERA
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