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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 300005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM 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.

Based on 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Hurricane Matthew at 30/0000 UTC is centered near 14.2N 68.1W or
about 130 NM...240 KM east-northeast of Curacao, moving west at
13 KT. Maximum sustained winds are 65 KT with gusts to 80 KT.
Estimated minimum central pressure has fallen to 987 mb.
Scattered to numerous strong convection are observed within 90 NM
in the S and 60 NM in the N semicircles...with a band of strong
convection within 60 Nm of a line from 13N65W to 10N66W. Matthew
is expected to slowly strengthen over the new few days as it
moves west-southwest over the central Caribbean. 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 along 26W/27W from
09N to 20N, moving west at 15 kt over the past 24 hours according
to satellite imagery. TPW imagery depicted abundant moisture
associated with the wave. However convection was limited to near
the intersection of the wave axis and and the monsoon trough.

The tropical wave noted earlier in the Central Atlantic along
34W/35W has been removed from the analysis. Satellite hovmoller and
easterly wave diagnostics suggest the vorticity associated with
the feature was derived from the tropical wave analyzed along
47W/48W. No significant convection was noted.

A tropical wave is in the Central Atlantic with axis from 15N45W
to 05N49W, moving west at 15 to 20 kt over the past 24 hours. The
wave was situated in an area of strongly diffluent upper level
which resulted in scattered moderate isolated strong convection
from 08N to 11N between 47W and 50W. 

The weak tropical wave in the west Caribbean along 89W earlier has
moved inland over the Yucatan peninsula and has become diffuse.
However, scattered moderate to strong convection was noted over
the Yucatan, Guatemala and Honduras.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends over Africa reaching the east Atlantic
near 16N16W through 10N33W to 09N45W. The ITCZ begins near 08N33W
to 07N59W. Aside from the convection associated with the tropical
waves, scattered moderate convection was noted from 06N to 09N
between 20W and 23W. and within 90-120 NM of the coast of Senegal. 

...DISCUSSION...

GULF OF MEXICO...

A broad deep layered cyclonic circulation centered over Kentucky 
and associated trough with mean axis along 85W dominated the 
eastern half of the Gulf of Mexico and provided support for a 
cold front extending from the Big Bend of Florida through
27.5N90W to 25N95W. Strong upper level subsidence was occurring in
the wake of the upper trough and was pressing southward as the
trough continued to amplify. A large anticyclone over Mexico near
23N104W dominated the flow over the southwestern third of the Gulf
with moderate to strong northwesterly flow aloft spreading mid
level moisture across the Bay of Campeche and the Yucatan peninsula.
Diffluent flow aloft was providing support for scattered showers
and isolated thunderstorms from Florida to to the Yucatan
channel...and weaker shower activity within 60-90 NM wither side
of a surface trough extending from 25N96W to 20N95W. The cold
front will continue moving south across the eastern Gulf during
the next 24 hours. Convection will prevail ahead of this boundary
affecting the southern Gulf waters.

CARIBBEAN SEA...

The main feature of concern in the Caribbean is Hurricane 
Matthew located south of Puerto Rico. Matthew remains embedded
within an area of diffluent anticyclonic flow aloft as it treks
westward. Please refer to the special features section above for
details. An upper- level trough extends across the Florida
Peninsula reaching the west Caribbean waters west of 80W.
Scattered showers are observed south of 16N between 80W-84W
affecting portions of Nicaragua and Honduras as well as their
adjacent waters. Isolated showers are observed south of 10N
between 78W-82W due to the proximity of the EPAC Monsoon Trough.
Scatterometer data depicts moderate to fresh northeasterly winds
across the basin west of 70W. Expect for Matthew to become a
hurricane within the next 24 hours. This system will continue
moving west through Friday.

...HISPANIOLA...

High cloudiness is spreading across the eastern Dominican
Republic in advance of Hurricane Matthew. The forecast track of
the hurricane should keep the bulk of the heavy precipitation to
the south of Hispaniola. However an increase in the overall
moisture could lead to localized heavy rain in orographically
favored areas. As Matthew turns northward late SUN or MON, the
potential exists for additional heavy rains over Haiti. For
additional information on Matthew, please refer to the special
features section above.

ATLANTIC OCEAN...

Two tropical waves are moving across the basin. Please refer to
the section above for details. A broad mid-level trough extends
across the southeast CONUS and covers the west Atlantic waters W
of 70W, supporting scattered showers and thunderstorms between
70W-80W. The remainder of the basin is dominated by a surface
ridge anchored by a 1036 mb high in the north central Atlantic
near 42N37W.

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

$$
COBB