AXNT20 KNHC 251024

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
624 AM EDT MON JUL 25 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 0600 UTC surface analysis and satellite imagery through
1015 UTC.


A tropical wave is in the eastern Atlantic from 09N-19N with axis
near 29W, moving W at 10 kt within the last 24 hours. The wave is
associated with a 1011 mb low centered near 13N29W. Meteosat
composite imagery show Saharan dry air and dust intrusion into the
wave environment, which is hindering convection at the time.

A tropical wave is in the west Atlantic from 08N-21N with axis
near 56W, moving at 30 kt within the last 24 hours. CIRA LPW from
the surface to 850 mb show moisture has increased in the northern
wave environment, which is supporting scattered moderate
convection from 17N-20N between 56W and 59W. Meteosat composite
imagery show Saharan dry air and dust in the remainder wave
environment, which hinder the convection elsewhere.

A tropical wave is in the Bay of Campeche S of 21N with axis near
95W, moving west at 20 kt within the last 24 hours. A cluster of
heavy showers and scattered tstms is in the Bay of Campeche S of
21N between 92W and 96W.


The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 14N17W and then continues along 14N25W to a 1011 mb
low near 13N29W to 08N34W to 08N46W. The ITCZ begins near 08N46W
and continues west to the coast of Guyana near 07N58W. Aside from
the convection associated with the waves, scattered moderate
convection is from 07N-12N E of 23W, from 05N-08N between 24W and
38W and from 06N-10N W of 50W.



Weak surface ridging continue to cover most of the basin N of 21N
and provides gentle to moderate return flow. South of 21N, in the
Bay of Campeche, a tropical wave is generating heavy showers and
scattered tstms S of 19N between 92W and 96W. The latest
scatterometer pass show fresh to strong NE winds within 120 nm off
the western Yucatan Peninsula. For further information about the
wave refer to the tropical waves section above. In the middle
levels, a broad low centered cover the SE Gulf while an inverted
trough moves across SW Gulf waters. Divergent flow aloft between
these two features along with abundant moisture in the basin
support scattered moderate convection from 22N-28N E of 90W.
Isolated showers are elsewhere N of 22N between 90W and 94W.
Expect showers to continue in the Bay of Campeche today. A
surface trough will develop and prevail in the SW Gulf the next
two days with high pressure dominating elsewhere.


A broad inverted trough in the upper levels along with shallow
moisture in the NW Caribbean support isolated showers and tstms N
of 15N W of 76W while farther east a surface trough support
similar precipitation activity in the Windward Passage. Isolated
showers are also possible for inland Hispaniola, the Mona Passage
and Puerto Rico. Scattered showers and tstms are within 90 nm off
Colombia and Panama associated with a 1009 mb low pressure near
09N76W. The gradient between this low and higher pressure in the
Atlc extending to the northern Caribbean support fresh to strong
winds S of 14N between 68W and 75W. This area of winds will
prevail the next two days, increasing in areal coverage before
Tuesday sunrise. Strong dry air subsidence from aloft support fair
weather elsewhere. A tropical wave will enter the eastern
Caribbean tonight.


A surface trough and associated broad surge of moisture support
isolated showers and tstms in the Windward Passage and isolated
showers inland Hispaniola as well as the Mona Passage. Moisture
associated with this trough will continue to enhance showers
across the Island today through early morning Tuesday.


Two tropical waves are moving across the Atlantic waters with no
significant convection. Please refer to the tropical waves
section above for details. Isolated showers are in the northern
Bahamas associated with a zone of diffluent flow aloft. Similar
convection is in the Turks and Caicos Islands associated with a
surface trough that is moving across Hispaniola today. Otherwise,
surface ridging and fair weather dominate elsewhere. No major
changes expected in the next two days.

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