[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310002
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
802 PM EDT Wed Aug 30 2017

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
2315 UTC.

...SPECIAL FEATURES...

Tropical Depression Harvey is centered near 31.2N 92.6W at
31/0000 UTC or about 9 nm SW of Alexandria Louisiana, moving NNE
at 7 kt. Estimated minimum central pressure is 998 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Rain is noted
on radar over SE Texas and W Louisiana from 30N-34N between 91W-
95W. Scattered moderate convection is observed further E, over the
NE Gulf of Mexico, the Florida Panhandle , and S Alabama, from
28N- 33N between 86W-89W. Catastrophic flooding is still expected
over southeast Texas and southwest Louisiana. See the latest
Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under
AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

T.S. Irma is centered near 16.4N 31.2W at 30/2100 UTC or about
417 nm W of the Cabo Verde Islands, moving W at 13 kt. Estimated
minimum central pressure is 1001 mb. Maximum sustained wind speed
is 50 kt with gusts to 60 kt. Scattered moderate convection is
from 14N-20N between 28W-34W. See the latest Intermediate Public
Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the
full Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21
KNHC for more details.

...TROPICAL WAVES...

A tropical wave over the central Atlantic extends from 24N48W to
09N49W, moving west at 15 kt. The wave coincides with an
amplified 700 mb trough in initial model wind fields. TPW
satellite imagery shows an area of modest deep layer moisture.
Satellite imagery also shows an area of Saharan dust to the west
of the wave. No convection is observed within this wave at this
time.

A tropical wave over the central Caribbean extends from 22N73W to
08N75W, moving west at 10 kt. The wave coincides with modest 700
mb troughing in initial model wind fields and curvature of low-
level winds in scatterometer data. SSMI TPW imagery shows this
wave is embedded in an area of modest deep layer moisture.
Scattered moderate convection is over E Cuba and Haiti. Scattered
moderate to isolated strong convection is along the coast of N
Colombia from 09N-14N between 72W-81W.

A tropical wave over the western Caribbean extends from 21N86W to
09N86W, moving west at 10 to 15 kt. The wave coincides with
subtle 700 mb troughing in initial model wind fields. TPW
satellite imagery shows this wave is embedded in an area of modest
deep layer moisture. Scattered moderate to isolated strong
convection is inland from the Yucatan Peninsula to S Nicaragua.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from 14N17W to 18N25W. The monsoon
trough continues W of Irma from 14N34W to 11N40W to 11N48W. The
ITCZ continues from 11N48W to 10N51W to 09N61W. Besides the
convection associated with Irma, scattered moderate convection is
from 06N-09N between 33W-38W. Similar convection is over the the
Windward Islands from 09N-13N between 57W-65W due to the ITCZ.

...DISCUSSION...

GULF OF MEXICO...

Tropical Depression Harvey is centered over Louisiana. A feeder
band is over the NE Gulf and the Florida Panhandle with
convection. Please see above. The tail end of a stationary front
is over N Florida from 29N80W to 31N86W. Scattered moderate
convection is N of the front over S Georgia. Further S, scattered
moderate convection is over W Cuba. An area of scattered showers
has developed over the Bay of Campeche south of 23N and west of
93W. Harvey is expected to slowly weaken and reach NW Mississippi
by Thursday evening. Little change is expected across the
remainder of the basin.

CARIBBEAN SEA...

Two tropical waves are moving across the Caribbean waters. See
the Tropical Waves section above for additional details. The
eastern portion of the E Pacific monsoon trough passes over the
southwest Caribbean along 10N. Low-level convergence near the
trough is producing scattered moderate convection over Costa Rica
and Panama. An area of scattered moderate convection is moving
across the Windward Islands. This activity will continue moving
west affecting the southeast Caribbean waters through the next 24
hours. Scatterometer data depicts moderate to fresh trades across
the basin.

...HISPANIOLA...

Scattered moderate convection is presently over Haiti due to a
tropical wave. Expect gradual clearing as the tropical wave moves
well W of the island.

ATLANTIC OCEAN...

T.S. Irma is over the eastern Atlantic, while a tropical wave is
moving over the central Atlantic. Refer to the sections above for
details about these features. A surface trough extends from 31N43W
to 27N44W with scattered moderate convection. The remainder of
the basin is under the influence of a surface ridge anchored by a
1027 mb high centered over the Azores near 38N27W, and a 1018 mb
high centered near 26N59W.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa
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