Tropical Weather Discussion
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AXNT20 KNHC 190517

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
117 AM EDT Sat May 19 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
0415 UTC.


A central Atlantic tropical wave has an axis that extends from
12N49W to 00N51W, 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 is within 300 nm of either side of
the wave axis.


The monsoon trough passes through the coastal sections of Guinea
near 10N14W to 04N19W. The ITCZ continues from 04N19W to 00N49W.
Besides the convection associated with the tropical wave,
scattered moderate and isolated strong convection are from 00N to
05N between 05W and 19W. Isolated moderate convection is within
240 nm of the ITCZ axis between 20W and 40W.



An upper-level trough with its axis along 87W is interacting with
a deep plume of tropical moisture to the east of the trough axis
to produce scattered showers and thunderstorms across the eastern
Gulf affecting the Florida peninsula, Florida Straits, and the
majority of Cuba. A weak ridge axis extends across the basin
along 28N producing mainly gentle to moderate winds. The only
exception is fresh SE winds near the SE Texas coast.

A new surface trough is developing just southeast of South
Florida and is expected move into the eastern Gulf by Sunday. The
upper- level 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 prevail.


An upper-level trough extends over the Yucatan Channel and the
northwest Caribbean. Upper-level diffluence on the eastern side
of this trough is supporting numerous showers and scattered
moderate convection N of 13N between 74W and 84W. The interaction
of the upper trough with the nearby E Pacific monsoon trough over
Panama is supporting clusters of moderate to strong convection S
of 13N between 76W and 83W. Broad high pressure over the
subtropical Atlantic continues to support 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
extreme SW Caribbean near the eastern Pacific monsoon trough. Wave
heights of 8 to 10 ft continue to occur over the S central
Caribbean as confirmed by a recent satellite altimeter pass and
current buoy data.

Over the next couple of days, the upper-level trough will remain
in place enhancing 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
basin into early next week.


A diffluent flow aloft to the east of an upper- level trough
currently over the eastern Gulf of Mexico is supporting scattered
moderate convection across Florida, the Bahamas, and Atlantic
waters mainly west of 74W. Radar and surface observations
indicate that a weak NE-SW oriented surface trough is developing
over the waters SE of southern Florida. To the east, a 1028 mb
high is centered over the central Atlantic near 33N55W. A 1030 mb
high is also over the central Atlantic near 34N37W. These centers
anchor a very broad ridge that spans the Atlantic waters east of
Florida to the northwest African coast. A recent scatterometer
pass indicates fresh to strong SE winds over a portion of the NW
Bahamas possibly associated with the tightening pressure gradient
between the aforementioned surface trough and the high pressure
ridge. The pressure gradient between the central Atlantic high and
lower pressures in the Caribbean is producing fresh to locally
strong easterly winds along the northern coast of Hispaniola and
eastern Cuba. Moderate to fresh tradewinds are occurring elsewhere
across the central and western Atlantic south 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 surface trough SE of S Florida will slowly drift NE across S
Florida and into the E Gulf this weekend, increasing the chances
for heavy rainfall over central and S Florida. Otherwise, the
overall pattern will change little over the weekend, with strong
winds expected to continue along the northern coast of Hispaniola,
and at times eastern Cuba.

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