[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071037
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
637 AM EDT Sat Sep 7 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
1030 UTC.

...SPECIAL FEATURES...

Hurricane Dorian is centered near 39.7N 68.1W at 07/0900 UTC or
130 nm SE of Nantucket Massachusetts moving NE at 22 kt.
Estimated minimum central pressure is 965 mb. Maximum sustained
wind speed is 75 kt with gusts to 90 kt. Scattered moderate to
strong convection is within 60 nm of the center and scattered
moderate convection is elsewhere in feeder bands north of 39N
between 65W-71W. Dorian will continue moving generally northeast
with an additional increase in forward speed is expected through
Sunday. On the forecast track, the center of Dorian should pass
to the southeast of extreme southeastern New England this morning,
and then move across Nova Scotia and Newfoundland later today and
tonight. Dorian is forecast to become a powerful post-tropical
cyclone over eastern Canada by tonight or early Sunday. 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 30.9N 42.1W at 07/0900
UTC or 860 nm WSW of the Azores moving NW at 15 kt. Estimated
minimum central pressure is 1002 mb. Maximum sustained wind
speed is 45 kt with gusts to 55 kt. Scattered moderate convection
is well northwest of the center from 29N-32N between 42W-50W. A
turn to the west-northwest is expected later today. A turn to the
north is then forecast on Sunday, followed by a turn to the
northeast with an increase in forward speed on Monday. 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 30W and south of 20N, moving W at 10-15
kt. A 1011 mb surface low is embedded in the wave environment
centered near 14N29W. Scattered showers are noted from 15N-17N
between 28W- 31W. 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. The chance of tropical cyclone
formation during the next 48 hours with this system is low.

An Atlantic tropical wave extends its axis from 14N47W to 06N49W,
moving W at 15 kt. Scattered showers are noted within 45 nm on
either side of the wave axis.

An eastern Caribbean tropical wave extends its axis along 68W and
south of 20N, moving W at 15-20 kt. Scattered showers are noted
across the northern portion of the wave.

A west-central Caribbean tropical wave extends its axis along 75W
and south of 18N, moving W at 5-10 kt. Scattered showers are noted
across the northern portion of the wave also.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 17N16W
to the low pressure mentioned in the Tropical Waves section above
near 14N29W to 10N42W. The ITCZ is from 10N51W to 09N61W. Aside
from the convection mentioned in the section above, scattered
moderate convection is moving off the coast of Africa along and
south of the monsoon trough mainly east of 17W.

GULF OF MEXICO...

A cold front is dropping southward across the eastern half of the Gulf
reaching the Florida Peninsula. This front enters the waters near
27N83W to 26N87W then becomes stationary to 28N90W. High pressure
is building across the far west Gulf, centered near 28N92W. To
the southwest, a thermal trough is moving west from the Yucatan
Peninsula to the Bay of Campeche enhancing winds and convection.
Latest scatterometer data depicts light to gentle winds across the
basin.

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

CARIBBEAN SEA...

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

Scattered moderate convection is noted over the southwest
Caribbean due to the EPAC's monsoon trough proximity. This
activity is south of 12N between 79W-82W. 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 prevail elsewhere.

Weak ridging will prevail north of the area through early next
week. Moderate to fresh trade winds are expected through mid
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 west Atlantic waters near 31N76W and
stretches to the coast of Florida near 28N80W. Scattered showers
are noted along this boundary. To the east, a 1016 mb surface high
is near 28N64W. A surface trough extends into the central
Atlantic from 31N58W to 27N61W with scattered showers. Another
trough is in the central Atlantic from 18N63W to 19N54W. This
trough is producing scattered showers and thunderstorms from 17N-
22N between 50W-60W.

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

$$

ERA
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