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AXNT20 KNHC 180505

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
105 AM EDT Fri May 18 2018

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
0400 UTC.


A central Atlantic tropical wave has an axis that extends from
11N45W to 01S46W, moving W at 10 to 15 kt. This wave appears as a
poleward surge in low level moisture and troughing at 700 mb.
Isolated moderate convection and showers are S of 07N between 40W
and the wave axis.


The monsoon trough passes through the coastal sections of Guinea
near 10N14W to 04N21W. The ITCZ continues from 04N21W to 01N30W
to 01N43W. Besides the convection associated with the tropical
wave, scattered moderate to isolated strong convection is from
01N to 08N between 03W and 22W. Isolated moderate convection is
from 02N to 06N between 22W and 40W.



A weak surface trough extends from the western Florida panhandle
near 31N86W to 30N89W supporting a line of thunderstorms along the
trough axis. An upper trough is over the eastern Gulf along 87W
and is interacting with a deep plume of tropical moisture E of the
its axis to produce numerous showers and embedded thunderstorms
east of 87W including Florida, the Florida Straits, and western
Cuba. A weak ridge axis extends from central Florida to a 1014 mb
high center over the western Gulf near 27N93W. This ridge
supports gentle to moderate flow over the majority of the Gulf
basin this morning, except for fresh SE winds near the SE Texas
coast, where a tighter pressure gradient exists between the high
center and lower pressures inland.

The surface trough over the NE Gulf will dissipate this morning.
A new surface trough will develop just east of S Florida this
weekend and move into the eastern Gulf by Sunday. The upper trough
over the eastern Gulf will remain for several days, and will
continue to be the focus for shower and thunderstorm activity
mainly over the far eastern Gulf, where deeper moisture and better
lift will be present.


An upper trough extends over the Yucatan Peninsula and the NW
Caribbean. Upper level diffluence on the eastern side of this
trough is supporting scattered moderate convection N of 18N W of
75W and S of 16N W of 80W. Broad high pressure over the
subtropical Atlantic supports moderate to fresh tradewinds over
the NW and E Caribbean, and fresh to strong winds over the
central Caribbean. Light winds are occurring over the SW Caribbean
near the eastern Pacific monsoon trough. Wave heights of 8 to 10
ft are occurring over the S central Caribbean as confirmed by an
recent satellite altimeter pass and current buoy data.

Over the next couple of days the upper trough will remain in
place with an enhancement of shower and thunderstorm activity
over the western Caribbean. The surface ridging pattern over the
Atlantic will persist, keeping a similar wind profile in place
across the Caribbean into the upcoming weekend.


An upper trough and surface trough over the eastern Gulf of Mexico
is supporting scattered showers and thunderstorms over the W
Atlantic W of 76W, including the N Bahamas. A 1029 mb high is
centered over the central Atlantic near 33N54W. A 1031 mb high is
centered over the E Atlantic near 35N35W. These high pressure
centers anchor a very broad ridge that spans the Atlantic waters E
of Florida to the NW Africa coast. The pressure gradient between
the central Atlantic high and lower pressures in the Caribbean and
eastern Gulf of Mexico support fresh to locally strong E to SE
winds along the northern coast of Hispaniola, and fresh SW winds
off the north Florida coast. Moderate to fresh tradewinds are
occurring across the central and western Atlantic S of 27N. Gentle
to moderate winds cover the central Atlantic N of 27N. Moderate
to occasionally fresh NE winds are occurring over the eastern

The overall pattern will change little over the next few days,
with ongoing convection possible W of 75W and strong winds
expected to continue along the northern coast of Hispaniola, and
at times eastern Cuba.

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