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000
AXNT20 KNHC 291206 AAA
TWDAT

Tropical Weather Discussion...UPDATED
NWS National Hurricane Center Miami FL
806 AM EDT THU SEP 29 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.

Updated for T.S. Matthew information

Based on 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Tropical Storm Matthew at 29/1200 UTC is centered near 14.1N
65.5W or about 260 NM S of San Juan Puerto Rico and about 230 nm
ENE of Curacao moving west at 14 KT. Maximum sustained winds are
60 KT with gusts to 75 KT. Estimated minimum central pressure is
995 mb. Numerous heavy showers associated with it are happening
from 12N to 16N between 60W and 65W. Scattered moderate convection
is elsewhere from 11N to 18N between 59W and 65W. Matthew is
forecast to become a hurricane tonight or early Friday morning.
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.

...TROPICAL WAVES...

A tropical wave is in the E Atlantic extending from 07N to 17N
with axis near 24W, moving at 15 kt over the past 24 hours
according to satellite and global model guidance. This wave is
newly introduced based on global tropical waves diagnostic
guidance and latest passes of scatterometer data. Abundant
moderate to high low level moisture and a diffluent wind
environment at the middle and upper levels support numerous
moderate to isolated strong convection from 12N to 16N between 21W
and 27W. Scattered moderate convection is elsewhere from 10N to
17N E of 29W.

A tropical wave is in the Central Atlc extending from 08N to 16N
with axis near 33W moving W at 15 kt over the past 24 hours. This
is a low amplitude wave in a region of unfavorable deep layer wind
shear. CIRA LPW imagery and Meteosat enhanced imagery show dry air
in the northern wave environment that along dust support lack of
convection at the time. Scattered showers are from 09N to 12N
between the wave axis and 39W.

A tropical wave is in the Central Atlc extending from 05N to 14N
with axis near 45W expected to move at 15 kt over the next 24
hours. Unfavorable deep layer wind shear is in the northern wave
environment supporting lack of convection N of 12N. CIRA LPW
imagery show a moderate moist environment elsewhere with pockets
of dry air mainly W the wave axis where isolated showers are
observed to 50W. Scattered moderate to isolated strong showers
are from 08N to 12N between 38W and 44W.

A tropical wave is in the W Caribbean extending from 09N to 20N
with axis near 86W moving W at 15 KT over the past 24 hours. The
wave is in a region of abundant low level moisture and favorable
deep layer wind shear that support isolated heavy showers and
tstms S of 20N between 81W and 87W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends over Africa reaching the east Atlantic
near 12N17W through 07N30W to 07N43W. Aside from the convection
associated with the tropical waves, scattered heavy showers are
from 04N to 10N E of 22W.

...DISCUSSION...

GULF OF MEXICO...

Weak low pressure dominates across the Gulf in the wake of an
already dissipated cold front in the NE basin and the presence of
a surface trough off the E coast of Mexico extending from 25N97W
to 18N95W. These features are providing the basin with gentle
variable wind flow. Aloft, a broad anticyclone covers the western
portion of the basin while an upper trough extends over the
eastern waters and Florida. Diffluent flow between these two upper
level features along with low level moisture in the southern basin
support scattered to isolated showers over the SE Gulf while the
surface trough generates heavy showers and tstms from 20N to 25N
W of 96W. A reinforcing cold front will move across the Gulf
waters Thu becoming stationary from N Florida to the central basin
to Tampico Mexico on Friday and dissipating Saturday.

CARIBBEAN SEA...

The main feature of concern in the Caribbean is T.S. Matthew
located over the E basin. Numerous heavy showers associated with
it are happening from 12N to 16N between 60W and 65W. Scattered
moderate convection is elsewhere from 11N to 18N between 59W and
65W. See special features for further details. Over the NW basin,
a tropical wave with axis near 86W generate isolated heavy showers
and tstms S of 20N between 81W and 87W. See the tropical waves
section for more details. Strong dry air subsidence and
unfavorable deep layer wind shear support fair weather elsewhere.
Fresh to strong winds are from 11N to 13.5N between 72W and 76W.
Gentle to moderate trades are elsewhere, except in the vicinity of
T.S. Matthew. Matthew is forecast to become a hurricane tonight or
early Friday morning.

...HISPANIOLA...

Currently fair weather conditions prevail across the Island. T.S.
Matthew is forecast to pass south of Hispaniola as a hurricane
Friday through Sunday. Cloudiness associated with Matthew is
expected to spread over the island today with an increase in
showers and thunderstorms late tonight into FRI. The heaviest rain
is expected Sunday, especially for W Hispaniola. The large
envelope of Matthew may result in the potential for locally heavy
rains over Hispaniola. This will greatly depend on the ultimate
track of Matthew. For additional information on Matthew please
refer to the special features section above.

ATLANTIC OCEAN...

A broad middle-level trough extends across the SE CONUS and covers
Atlc waters W of 68W, supporting scattered showers and tstms in
that area N of 22N. The remainder basin is being dominated by a
broad surface ridge anchored by a 1035 mb high in the north
central Atlantic near 40N42W.

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

$$
RAMOS

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