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Atlantic Tropical Weather Discussion

AXNT20 KNHC 291154 AAA

Tropical Weather Discussion...AMENDED
NWS National Hurricane Center Miami FL
754 AM EDT FRI JUL 29 2016

Amended for Special Features section

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.


A tropical wave is in the far east Tropical Atlantic with axis
that extends from 18N22.5W to a 1009 mb low near 11N22.5W. These
features are moving west at about 10 kt over the past 24 hours.
The wave coincides well with a low to mid level trough extending
northward through the Cabo Verde Islands. Scattered moderate to
isolated strong convection is evident within 90 nm of the center.
Despite increased convection, the earlier microwave imagery
showed the low level structure is still fairly weak at this time.


A tropical wave is moving over the central Tropical Atlantic with
axis from 19N42W to 11N42W, moving west at 15 to 20 kt over the
past 24 hours. The tropical wave appears to have a high amplitude
in the lower to mid levels of the atmosphere based on GOES high
density winds with copious deep layer moisture in SSMI Total
Precipitation Water Vapor Imagery. Recent scatterometer data also
indicates associated surface troughing with an area of fresh
trades on the northern portion of the surface trough from 19N to
15N between 40W and 45W. Scattered moderate convection is also
noted with this tropical wave along the axis from 15N to 13N
between 40W and 43W.

A tropical wave is over western Tropical Atlantic from 15N55W to
08N55W, moving west 10 to 15 kt over the past 24 hours. This is a
fairly weak and low amplitude tropical wave with very limited
moisture. It is entering an area with fairly dry mid to upper
levels and westerly shear. If the tropical wave persists through
this area it will have little influence on the sensible weather
for the next several days as it tracks west.

A tropical wave is moving through the Gulf of Honduras, reaching
from the western tip of Cuba through central Honduras near 16N85W.
Scattered moderate convection is noted across the northwest
Caribbean west of 85W. 


The Monsoon Trough extends across North Africa into the east
Tropical Atlantic near 20N16W to 1009 mb low near 11N22.5W to
10N45W. The ITCZ begins from that point and continues to 08N55W.
Aside from the convection related to the tropical waves and
surface lows, scattered moderate to isolated strong convection is
noted within 120 nm north of the monsoon trough between 45W and



Divergence aloft on the east side of an upper level low pressure
area centered over the southwest Gulf of Mexico is enhancing the
regular evening trough that emerges off the northwest coast of the
Yucatan peninsula. Scattered moderate to isolated strong
convection was noted in the Bay of Campeche earlier this evening,
but this has since diminished. The surface trough reaches from
22N92W to 18N94W, with an accompanying trough located farther
north over the north central Gulf from 28N89W to 25N92W. Surface
ridging prevails from the western Atlantic across Florida into the
eastern Gulf. Generally gentle to light flow prevails, except for
locally moderate to fresh winds near the base of the trough in the
Bay of Campeche. Scattered moderate convection will persist today
as the upper low pressure track westwards through the next 24
hours, ahead of the northern portion of a tropical wave moving
through Yucatan today. The tropical wave enhance the usually
evening trough off western Yucatan tonight and tomorrow night.
Otherwise little change is expected.


An upper trough extends from 25N60W through the Mona Passage to
the central Caribbean. This is supporting a lower to mid level
trough moving across the Leeward and Windward Islands currently.
An associated surface trough was resolved in recent Rapidscat data
moving into Barbados. Little weather is associated with this deep
layer trough however other than a few showers and brief increases
in winds to 20 kt. The lower to mid level trough is expected to
dampen out as it moves west-northwest through the next 24 to 48
hours. with little to no presence a surface trough. Otherwise,
fresh to strong trade winds persist over the central Caribbean
between the tropical wave exiting to the west and approaching deep
layer trough. 


The upper trough will likely support scattered moderate to
isolated strong convection over interior areas of Hispaniola this
afternoon and evening.


Three tropical waves are moving across the Tropical Atlantic.
Please refer to the section above for details. A 1019 mb surface
high is centered across the west Atlantic near 27N75W. To the
east, another surface ridge prevails extending across the
remainder of the basin anchored by a 1031 mb high near 41N32W.
Little change is expected through the next 24 hours.

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