[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082340
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
740 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 1800 UTC surface analysis and satellite imagery through
2320 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Dorian is centered near 51.0N 57.5W at
08/2100 UTC or 55 nm WSW of St. Anthony, Newfoundland moving NE
at 20 kt. The estimated minimum central pressure is 968 mb and
maximum sustained wind speed is 55 kt with gusts to 65 kt.
There are scattered showers moving across northeastern Canada.
Dorian will move east-northeast by Monday through Tuesday. On the
forecast track, the center of the post- tropical cyclone should
move near or over northern Newfoundland or eastern Labrador during
the next few hours, then move away from Atlantic Canada later
tonight. The post-tropical cyclone should continue to weaken, and
it is forecast to be absorbed by another low pressure system on
Tuesday. 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 35.3N 49.4W at 08/2100
UTC or 1080 nm W of the Azores moving N at 15 kt. The estimated
minimum central pressure is 995 mb and the maximum sustained wind
speed is 55 kt with gusts to 65 kt. Scattered moderate convection
is observed from 33N-36N between 48W-53W. A turn to the northeast
with an increase in forward speed is expected to begin Monday
morning, with a further increase in forward speed occurring
through Monday night. Some slight strengthening is possible
through tonight. Gradual weakening is expected to begin Monday
and Gabrielle is expected to transition to an extratropical low by
Tuesday night. 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 19W S of 20N,
moving W at around 10 kt. Scattered moderate convection is in the
vicinity of the wave axis from 06N-12N between 17W-20W.

An eastern Atlantic tropical wave extends its axis along 39W S of
20N, moving W at 20 kt. A 1011 mb surface low is embedded in the
wave environment centered near 15N39W. Scattered showers are
noted near the low from 12N-18N between 36W-42W. 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 54W S of 16N,
moving W at 10 kt. Scattered showers are noted from 07N-12N
between 51W-57W.

A west-central Caribbean tropical wave extends its axis along 76W
S of 19N, moving W at 15 kt. Scattered showers and thunderstorms
are noted along the northern portion of the wave near Jamaica.

A western Caribbean tropical wave extends its axis along 83W S of
18N, moving W at 15 kt. Scattered thunderstorms are occurring in
the northwest Caribbean from 18N-20N between 81W-84W, impacting
parts of the Cayman Islands. Additionally, scattered moderate
convection is moving west across the countries of Honduras,
Nicaragua, and Costa Rica with some convection occurring in
the eastern Pacific.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Mauritania near
17N16W to the low pressure mentioned in the Tropical Waves
section above near 15N39W to 09N47W. The ITCZ begins near 09N47W
to 11N54W, then continues W of a tropical wave near 10N55W to the
coast of Guyana near 08N59W. Aside from the convection mentioned
in the section above, scattered moderate convection is noted from
07N- 16N between 21W- 48W.

GULF OF MEXICO...

A middle to upper level low is centered over the western Gulf
which is igniting scattered thunderstorms from 22N-26N between
89W-95W. Two troughs are analyzed in the Gulf: one from 19N91W to
26N88W and the other from 24N85W to 26N83W. Some scattered
moderate to strong convection is moving from southern
Mexico/Yucatan into adjacent waters, mostly S of 22N and E of 94W.
Otherwise, surface ridging prevails anchored by a 1017 mb high
near 28N94W. Latest scatterometer data depicts light to gentle
winds are seen across the basin.

High pressure ridging will prevail just N of the basin through
the week. The ridging will maintain gentle to moderate easterly
flow, except pulsing to fresh NW of the Yucatan Peninsula each
evening.

CARIBBEAN SEA...

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

Scattered moderate to strong convection is seen over the Greater
Antilles from eastern Cuba to the Dominican Republic. Some of this
activity is moving into adjacent waters. Scattered thunderstorms
are also seen moving across parts of the Lesser Antilles. Latest
scatterometer data depicts moderate to fresh trades in the south-
central Caribbean with light to gentle trades elsewhere.

High pressure ridging will prevail N-NE of the basin through the
week. The ridging will maintain moderate trades, except pulsing to
fresh to strong in the S central Caribbean.

ATLANTIC OCEAN...

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

A 1019 mb surface high is near 30N69W. A surface trough extends
across the central Atlantic from 29N64W to 31N61W and another
trough to the east from 27N62W to 31N57W. Scattered showers are
present in the vicinity of both troughs. Another trough to the
south is noted from 20N58W to 23N65W with scattered thunderstorms
from 16N-24N between 56W-68W. 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 the
week.

$$
AKR
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