[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 PM 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Dorian is centered near 50.0N 59.4W at
08/1800 UTC or 40 nm E of Chevery Quebec and 145 nm NNE of Cape
St. George Newfoundland moving NE at 23 kt. Estimated minimum
central pressure is 965 mb. Maximum sustained wind speed is 70 kt
with gusts to 85 kt. Numerous showers are moving across eastern
Canada. Dorian will be moving near or over northwestern
Newfoundland or eastern Labrador this afternoon and then enter
the North Atlantic this evening. The post-tropical cyclone is
forecast to drop below hurricane strength after passing
Newfoundland later today, and it is forecast to be absorbed by
another large low pressure system in a couple of days. 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 33.8N 49.0W at 08/1500
UTC or 1260 nm W of the Azores moving NNW 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 33N-36N between 47W-50W. A turn
to the north is forecast later today, followed by a turn to the
northeast on Monday with an increase in forward speed. Some
strengthening is possible through Monday. Gabrielle is then
expected to weaken starting Monday night as it begins a transition
to become an extratropical low. 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 19N,
moving W at around 10-15 kt. Scattered moderate convection is in
the vicinity of the wave axis from 04N-13N between 12W-21W.

An eastern Atlantic tropical wave extends its axis along 34W S of
20N, moving W at 10-15 kt. A 1011 mb surface low is embedded in
the wave environment centered near 14N37W. Scattered showers are
noted near the low from 12N-18N between 33W-40W. Some slow
development of this system is possible during the next several days
while the low moves westward across the 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 53W S of 15N,
moving W at 10-15 kt. Scattered showers are noted from 07N-12N
between 51W-55W.

A west-central Caribbean tropical wave extends its axis along 74W
S of 18N, moving W at 15-20 kt. Scattered showers are noted along
the northern portion of the wave near Jamaica, and scattered
moderate isolated strong convection south of 10N mostly near the
the NW coast of Colombia and Panama.

A west-central Caribbean tropical wave extends its axis along 81W
S of 17N, 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 18N16W
to the low pressure mentioned in the Tropical Waves section above
near 14N37W to 09N44W. The ITCZ begins near 09N44W to 08N51W.
Aside from the convection mentioned in the section above,
scattered moderate convection is from 10N-12N between 41W-47W.

GULF OF MEXICO...

A surface trough stretches across the eastern Gulf from the west
coast of Florida near 26N81W to 22N84W. A few showers are along
the boundary. In the Bay of Campeche, another surface trough is
analyzed from 23N90W to 17N93W. Scattered moderate showers and
storms are noted near this trough from 20N-25N between 88W-95W.
High pressure is building across the far western Gulf, anchored
by a 1017 mb high centered near 26N92W.

Weak high pressure will remain over the area through next week,
with mainly gentle to moderate winds expected, except for
occasionally fresh winds near the Yucatan Peninsula mainly in the
evenings.

CARIBBEAN SEA...

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

An upper-level high is centered in the NW Caribbean and an upper
low meanders into the eastern Caribbean Sea. This is causing
scattered showers across the Greater Antilles. Scattered moderate
convection is also noted in the SW basin from the monsoon trough,
S of 10N between 75W-83W. Scattered moderate convection is also
noted north of the Gulf of Honduras.

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 27N71W. A surface trough extends
across the central Atlantic from 31N61W to 29N64W with scattered
showers and thunderstorms occurring along and north of the trough,
and another trough to the east from 31N58W to 28N60W. Scattered
showers are present in the vicinity along 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.

$$
MTorres
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