[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 062351
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
751 PM EDT Fri Sep 6 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...

Hurricane Dorian is centered near 36.9N 72.7W at 06/2100 UTC or
290 nm SSW of Nantucket, Massachusetts and 600 miles SW of
Halifax, Nova Scotia moving NE at 20 kt. The estimated central
pressure is 958 mb and the maximum wind speed of 80 kt with gusts
to 100 kt. Scattered moderate to isolated strong convection is
within 60 nm of the center and scattered moderate convection is
elsewhere in feeder bands from 33N-43N between 66W-75W. Dorian
will continue moving generally NE with an additional increase in
forward speed is expected through Sunday. On the forecast track,
the center of Dorian should move to the southeast of extreme
southeastern New England tonight and Saturday morning, and then
across Nova Scotia late Saturday or Saturday night. Some
strengthening is possible during the next 24 hours. After that
time, Dorian is forecast to become a post-tropical cyclone with
hurricane-force winds Saturday night or Sunday while it is near or
over eastern Canada. 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 27.9N 39.6W at 06/2100
UTC or 880 nm SW of the Azores moving NW at 15 kt. The estimated
minimum central pressure is 1003 mb and maximum sustained wind
speed is 40 kt with gusts to 50 kt. Scattered moderate convection
is well north of the center from 28N-32N between 36W-44W. A turn
to the west-northwest with a slight decrease in forward speed are
expected on Saturday. Gabrielle is forecast to gradually turn to
the northwest and north on Sunday, then move at a faster pace to
the northeast on Monday. By late Sunday or Monday, Gabrielle is
anticipated to become a hurricane. See latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC or
the website hurricanes.gov for more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave near the Cape Verde Islands
extends its axis along 27W S of 19N, moving W at 15 kt. A 1011 mb
low is embedded on the wave axis near 14N27W. Scattered showers
with isolated thunderstorms are noted from 15N-17N between 26W-
30W. Little, if any, development of this disturbance is expected
for the next couple of days. Environmental conditions are likely
to become more conducive for a tropical depression to form by
Tuesday or Wednesday while the system moves westward across the
tropical Atlantic Ocean. The chance of tropical cyclone formation
during the next 48 hours is low.

An Atlantic tropical wave that was once associated with Gabrielle
is now along 44W S of 14N, moving W at 10-15 kt. Scattered
showers and thunderstorms are seen from 07N-10N between 44W-46W.

An eastern Caribbean tropical wave extends its axis along 64W S
of 20N, moving W at 10-15 kt. Scattered showers are seen within
100 nm of the axis.

A central Caribbean tropical wave extends its axis along 74W S of
18N, moving W at 15 kt. Scattered showers are over Hispaniola and
in the north-central Caribbean. Enhanced convection is seen across
northern Colombia.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 15N17W
to the low pressure mentioned in the tropical waves discussion near
14N27W to 09N43W. The ITCZ is from 09N46W to 10N61W. Aside from
the convection mentioned in the section above, numerous moderate
to strong convection is moving off the coast of Africa from 08N-
13N and E of 16W. Scattered showers and thunderstorms are seen
along the monsoon trough from 07N-12N between 30W-43W. Isolated
thunderstorms are seen along the ITCZ from 08N-10N between 46W-
53W.

GULF OF MEXICO...

A cold front is dropping southward across the Gulf and Florida.
This front enters the waters near 28N83W and stretches westward to
New Orleans, Louisiana near 30N90W. High pressure is seen across
the western portions of the Gulf anchored by a 1017 mb high near
29N95W. Two troughs are analyzed in the Bay of Campeche, the first
begins near 18N94W to 22N92W, and the second is from 19N96W to
24N96W. Scattered moderate convection is seen across the Bay of
Campeche from 19N-25N between 91W-97W. Latest scatterometer data
shows light to gentle winds across the Gulf.

A cold front over the northeast Gulf will shift southward and
dissipate through early Sat. Weak high pressure will persist
across the northwest Gulf through early next week, with gentle to
moderate winds expected.

CARIBBEAN SEA...

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

Isolated thunderstorms are seen across the western Caribbean from
10N-19N and W of 79W. Isolated thunderstorms are also seen across
the Greater Antilles with some of this activity reaching adjacent
waters in the Caribbean. Otherwise, upper level ridging is
keeping fair skies across most of the basin. Latest scatterometer
data depicts gentle to moderate trades in the central Caribbean,
with light to gentle trades elsewhere.

Weak ridging will prevail north of the area through early next
week. Moderate to fresh trade winds are expected through early
next week, except increasing to moderate to fresh in the south
central Caribbean Mon, then fresh to strong thereafter.

ATLANTIC OCEAN...

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

A cold front enters the waters near 31N77W and stretches to the
coast of Florida near 29N81W. Showers and thunderstorms are seen
along this boundary, with some convection occurring from 27N-29N
between 79W-80W. A weak 1017 mb high is near 28N66W. A trough
extends into the central Atlantic from 26N63W to 31N58W. Showers
are within 50 nm of the trough. Another trough is in the central
Atlantic from 18N60W to 16N50W. This trough is producing scattered
showers and thunderstorms from 16N-22N between 49W-59W. Scattered
thunderstorms are also seen to the west of T.S. Gabrielle, from
26N-29N between 46W-49W.

Large northerly swell from distant Dorian will dominate the
waters mainly north of 28N into Sunday. A return to tranquil
marine conditions is expected next week.

$$
AKR
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