Tropical Weather Discussion
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AXNT20 KNHC 142335

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
635 PM EST Tue Nov 14 2017

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
2230 UTC.


A 1007 mb low pressure center is near 35N29W, about 200 nm to the
SSW of the Azores. A surface trough extends S from the low center
to 30N28W to 25N34W. Scattered moderate convection is within 300
nm east of the low, and within 180 nm east of the trough axis N
of 30N. This system has a medium chance to become a subtropical
cyclone during the next couple of days before upper- level winds
become unfavorable. Regardless of development, this low is
expected to produce winds to near gale force during the next day
or two while it moves slowly northeastward. For additional
information on this system, see High Seas Forecasts issued by
Meteo France under WMO header FQNT50 LFPW and on the web at


The monsoon trough extends from the African coast near 07N12W to
08N21W. The Intertropical Convergence Zone axis extends from
08N21W to 04N30W to the coast of South America near 04N51W.
Isolated moderate convection is from 03N to 09N between 12W and
33W, and from 06N to 12N between 45W and 53W.



Dry air and subsidence covers much of the Gulf basin this evening
as a surface ridge axis extends from high pressure centered over
the Ohio Valley to the western Gulf. Gentle to moderate NE to E
winds cover the basin, except moderate to fresh over the SE Gulf.
Over the next 24 hours winds over the eastern Gulf will increase
to fresh to strong as the area of high pressure builds southward
toward the SE United States.


A pair of surface troughs extend over the NW Caribbean from
western Cuba near 21N77W to 18N81W, and from 17N83W to 16N88W. The
combination of these surface troughs and an upper trough over the
region supports numerous showers and scattered thunderstorms
within 120 nm SE of the surface troughs. A 1007 mb low is centered
over the SW Caribbean near 11N77W with a surface trough extending
from the low to near 15N80W. Scattered moderate convection covers
much of the SW Caribbean S of 17N between 72W and 82W. Fresh NE
winds are occurring over the NW Caribbean to the north of the
surface troughs. Mainly gentle to moderate winds are S of these
troughs and west of about 70W. Moderate easterly trades are E of
70W. Over the next 24 hours the troughs will merge with the low as
the low drifts slowly NNE. Convection will continue over the SW
Caribbean in the vicinity of the low.


Numerous showers and scattered thunderstorms will persist over
the area the next couple of days as deep moisture is pulled NE
across the area due to an upper trough to the west. Convection
will be heaviest in the afternoon and evening hours during maximum
heating. Localized flooding and life- threatening mud slides are
also possible during this time.


A slowly moving cold front extends from 31N72W to 27N80W. Fresh to
strong NE winds are N of the front. Scattered showers and
thunderstorms are within 90 nm SE of the front. A prefrontal
trough extends from 30N67W to 23N75W. This trough is interacting
with an upper trough to the west to produce widespread showers and
isolated thunderstorms within 450 nm E of the surface trough
axis. A 1020 mb high is centered near 30N48W. A special feature
low is north of our eastern portion of the area of discussion.
Please refer to the special features section for more details. A
surface trough extends from 24N28W to 16N30W. This trough is void
of convection. Over the next 24 hours a pair of low pressure
centers will develop along the western Atlantic surface trough,
with increasing winds and seas spreading NE with the lows.

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