AXNT20 KNHC 281743

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
143 PM EDT WED SEP 28 2016

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
1730 UTC.


The tropical wave and surface low described in this section in the
previous discussion has developed into Tropical Storm Matthew as
of 28/1500 UTC, centered near 13.4N 60.7W, or about 31 nm
southeast of St. Lucia and St. Vincent. The minimum central
pressure of Matthew is 1008 mb and is moving west at 18 kt.
Maximum winds are 50 kt with gusts to 60 kt. Scattered moderate to
strong convection is observed from 11N-17N between 55W-64W
affecting the Lesser Antilles and eastern Caribbean waters. Please
refer to the NHC forecast/advisory under AWIPS/WMO headers WTNT24
KNHC/TCMAT4, or visit the NHC website at http://hurricanes.gov for
additional details.


An Atlantic Ocean tropical wave extends its axis from 18N28W to
05N28W, moving westward at 10 to 15 kt. Abundant moisture prevails
east of the wave's axis as noted in TPW imagery. The precipitation
observed in the vicinity of this wave is related to the Monsoon
Trough and prevails east of 27W.

A tropical wave extends across the western Caribbean with axis
from 17N79W to 08N79W, moving westward at 15 kt. The wave is
moving into the area of an upper-level low currently centered near
16N82W. Scattered moderate convection is observed in the area
where the wave interacts with the Monsoon Trough mainly south of
11N between 76W-81W.


The Monsoon Trough extends over Africa reaching the east Atlantic
near 10N15W to 09N28W to 07N34W to 08N44W. Scattered moderate
convection is observed from 05N-11N between 14W-26W. Isolated
showers prevail along the remainder of the boundary.



An upper-level anticyclonic circulation is centered over eastern Mexico
near 23N99W. Upper-level anticyclonic wind flow prevails across
most the basin. An upper-level trough extends east of 83W across
the far east Gulf waters and Florida Peninsula. At the surface; a
trough extends over the Bay of Campeche from 27N95W to 20N95W.
Scattered moderate convection prevails along this boundary
affecting the waters west of 93W. To the northeast; a cold front
extends from 28N91W to 30N86W. Scattered showers are observed
north of 26N and east 89W. Gentle to moderate southeasterly winds
prevail across the basin. Expect during the next 24 hours for the
cold front to continue moving east with showers. The surface
trough over the Bay of Campeche will continue enhancing convection.


A tropical wave is moving across the western Caribbean while T.S
Matthew is will enter the eastern Caribbean within the next few
hours. Please refer to the section above for details. An upper-
level low is centered near 16N82W enhancing convection from 11N-
14N and west of 82W affecting portions of Nicaragua. The Monsoon
Trough extends along 10N between 75W-80W with scattered moderate
convection. An upper-level trough extends from 68W-75W supporting
isolated convection just north of 14N. Scattered moderate
convection is entering the far east Caribbean waters due to
Matthew. Scatterometer data depicts moderate to fresh trades
across the basin. Expect during the next 24 hours for the tropical
wave and Matthew to move west across the basin.


An upper-level trough extends from 68W-75W across the island supporting
isolated convection just north of 17N between 69W-71W. Expect for
this trough to weaken within the next 24 hours. Isolated showers
are still expected.


T.S. Matthew has developed in the central Atlantic while a tropical wave
extends along 28W. Please refer to the sections above for
details. A surface trough extends across the west Atlantic from
25N79W to 32N76W. Scattered moderate convection is north of 26N
between 75W-79W. To the east; a weakening stationary front extends
over the central Atlantic from 29N52W to 31N44W. No significant
convection is observed with this feature at this time. The
remainder of the basin is under the influence of a surface ridge
anchored by a 1030 mb high centered near 38N48W and a 1032 mb high
near 39N43W.

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