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Atlantic Tropical Weather Discussion

AXNT20 KNHC 270603

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 AM EDT WED JUL 27 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.


A tropical wave is in the eastern Atlantic from 09N-19N with axis
near 27W, moving at 15 kt within the last 24 hours. Meteosat
composite imagery show Saharan dry air and dust in the northern
wave environment. Moderate moist air from surface to 850 mb and
divergent flow in the middle to upper levels support scattered
moderate convection from 07N-11N between 22W and 30W.

A tropical wave is in the central Atlantic from 09N-17N with axis
near 40W, moving west at 20 kt within the last 24 hours. CIRA LPW
imagery show mainly dry air from the surface to 850 mb associated
with this wave. The dry air is due to the presence of abundant
Saharan dry air and dust, which is hindering convection at the

A tropical wave is in the central Caribbean from 11N-21N with
axis near 69W, moving west at 20 kt within the last 24 hours. The
wave is associated with shallow moisture according to CIRA LPW
imagery. Aloft, water vapor imagery show strong subsidence across
the central-southern Caribbean, which is inhibiting convection in
that region at the time. However, the wave supports scattered to
isolated showers over Hispaniola and its coastal waters.


The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 18N16W to 11N24W to 10N34W to 08N45W. The ITCZ
begins near 08N45W and continues to the coast of Guyana near 06N57W.
Aside from the convection related to the tropical wave in the east
Atlantic, heavy showers and tstms are from 06N-19N E of 19W.
Scattered showers are from 02N-08N between 30W and 44W.



A middle to upper level low covers the NW basin tonight while a
broad upper level inverted trough formerly in the W Caribbean has
moved to the E Gulf waters, however associated with dry air
subsidence. This dry air is limiting the convection to isolated
showers and tstms E of a line from 29N83W to 22N87W. Moisture
inflow from the Caribbean by SE flow and the low aloft support
scattered to isolated showers N of 23N W of 86W. In the SW Gulf, a
surface trough off the western Yucatan Peninsula support scattered
showers and tstms in the eastern Gulf of Campeche S of 20N.
Otherwise, mainly E-SE moderate wind covers the basin due to weak
surface ridging. The exception is the Bay of Campeche where NE
moderate to fresh flow is noticed. Weak surface pressure and
return flow will prevail the next two days.


The short-wave upper trough formerly over the central Caribbean is
now over eastern Cuba, thus supporting isolated showers and tstms
over the Island coastal waters. To the west, the eastern portion
of a broad inverted upper-level trough supports isolated showers
and tstms in the NW Caribbean, including the western Gulf of
Honduras. In the SW basin, the monsoon trough supports heavy showers
and tstms within 120 nm of the coast of northern Panama, Costa
Rica and southern Nicaragua. A tropical wave is moving across the
central Caribbean where it generates scattered to isolated
showers across Hispaniola and adjacent waters. See the tropical
waves section above for further details. Scatterometer data depict
fresh to strong winds in the south-central basin S of 16N and
moderate trades elsewhere. Showers will continue across Hispaniola
tonight as the wave continue to move westward. The next tropical
wave will enter the east Caribbean during the weekend.


A tropical wave is moving across the central Caribbean where it
generates scattered to isolated showers across Hispaniola and
adjacent waters. Convection associated with this wave is expected
to continue through Wednesday evening.


Two tropical waves are moving across the basin and a third wave is
over the central Caribbean, but extending to 21N. Please refer to
the tropical waves section for more details. With little support
aloft, a stationary front in the central Atlantic will start to
weaken. The tail of this front extends to the area of discussion
from 30N55W SW to 26N62W and support isolated showers within 60 nm
either side of the boundary. Surface high pressure is across the
remainder basin being anchored by a 1033 mb high centered N of
the Azores Islands. Expect for the surface ridge to persist
through the next 24 hours and the front to dissipate. 

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