Tropical Weather Discussion
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AXNT20 KNHC 270006

Tropical Weather Discussion NWS National Hurricane Center Miami
FL 805 PM EDT WED OCT 26 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
2330 UTC.


Gale-force winds are forecast for the areas of Agadir,Casablanca,
and Madeira. Please refer to the METEO-FRANCE High Seas Forecast,
that is listed under the following links: MARINE...BULLETINS
EXPERTISES...GRAND LARGE...METAREA II...or on the website:
METAREA2. This is for the forecast that is valid until 27/1200 UTC.


An Atlantic Ocean tropical wave extends from 14N39W to 04N38W,
and has been moving slowly west at 05 to 10 kt over the past 24
hours. This low level wave is approaching the mean axis of an
upper trough, with associated diffluence enhancing scattered
moderate to strong convection from 04N to 10N within 180 nm
either side of the wave axis and along the monsoon trough as
well. The debris moisture from this convection is advected
northeast and east across the Atlc from 10N to 18N to the east
of 38W and continues eastward across the African coast.

A Caribbean Sea tropical wave extends its axis from 20N65W to
11N65W, and has been progressing slowly west at 05 to 10 kt
during the past 24 hours. A low to mid level trough extends
south-southwest across the e Caribbean with diffluence east of
its axis enhancing an area of scattered moderate convection from
14N to 17N within 180 nm east and within 210 nm west of the
tropical wave axis.


The Monsoon Trough extends southwest across the African coast at
10N13W to 08N20W, then turns abruptly northwest to 13N20W, then
turns southwest through an embedded 1012 mb surface low at
09.5N36W to 08.5N38W, where scatterometer winds indicate a
transition to an ITCZ, which continues west to 10N54W where it
loses identity. Except as previously described near the tropical
wave along 39W, scattered moderate isolated strong convection is
observed from 05N to 15N between 10W and 38W.



A northeast to southwest orientated surface ridge extends from
the Florida big bend to the west-central Gulf of Mexico with a
weak inverted coastal trough observed n of the ridge axis along
the Texas coast. An inverted heat trough is analyzed s of the
ridge axis over the Yucatan Peninsula. Isolated showers and
thunderstorms are observed across the southwest Gulf waters
where a weak inverted trough was previously analyzed. Similar
convection is observed along a north to south line from 26N90W
to 22N90W. This convection is flaring in an area of upper
diffluence to east of an upper trough over the western Gulf of
Mexico. Dense upper debris moisture, originating from
dissipating convection over the northwest Caribbean, is advected
north across the southeast Gulf of Mexico, and then turns east
across southern Florida and the Straits of Florida. The ridge
will shift north on Thu with a broad low level trough developing
across the southwest Gulf.


A tropical wave and associated convection over the eastern
Caribbean is previously described. A shearline extends from
Hispaniola to just south of Jamaica to the Gulf of Honduras. The
monsoon trough extends east to west across the far southwest
Caribbean between 09N and 11N. An upper ridge extends from
Colombia to western Cuba with associated upper diffluence
enhancing considerable convection over the west Caribbean to the
north of 12N and mainly along 80W. The resultant dense debris
moisture covers the entire west Caribbean with narrow bands of
these cirrus clouds streaming east across the east Caribbean as
well. The tropical wave will continue moving west during the
next 24 hours, and may enhance convection over Puerto Rico and
Hispaniola especially during peak afternoon heating.


An east to west shearline extends across the northern Dominican
Republic and dissects Haiti from northeast to southwest with
mainly moderate showers currently observed along the boundary,
but convection will likely become more widespread tomorrow


A tropical wave is moving across the tropics and is previously
mentioned. A frontal trough extends from 32N57W to Hispaniola
with scattered moderate isolated strong convection within about
240 nm east of the boundary. A broad surface ridge is analyzed
west of this dissipating front, with broken to overcast
cirriform clouds observed south of 27N. A broad ridge covers
most of the area north of 20N and east of the frontal trough
with a surface trough analyzed across the tropics from 20N52W
to 15N54W, and accompanied by scattered showers within 150 nm
either side of a line from 17N46W to 20N53W. A 1002 mb low is
centered over the far east Atlantic near 32N18W with a surface
trough extending south to 21N22W. Gale-force winds are forecast
across the sub-tropical waters east of the low. Please refer to
the Special Features section above for details.

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