Tropical Weather Discussion
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AXNT20 KNHC 181043

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
642 AM EDT Wed Apr 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.


The monsoon trough extends from the coast of Africa near 09N14W
to 05N15W to 03N25W. The ITCZ continues from 03N25W to 02N45W.
Scattered moderate convection is within 30 nm south of the monsoon
trough axis between 15W and 20W, and within 60 nm north of the
ITCZ between 35W and 45W.



Fresh SE winds persist off the coast of Texas between the ridge
and lower pressure forming over Texas. Seas are 5 to 7 ft in the
northwest Gulf accordingly, with 2 to 4 ft elsewhere. No shower
or thunderstorm activity is noted, and visibility remains
unrestricted across the basin.

The ridge over the northern Gulf will continue to shift east
ahead of a cold front moving east through the Southern Plains,
allow the fresh SE return flow over the northwest Gulf to
diminish through late Wed. The front will enter the northern Gulf
Thu, stall from southwest Florida to south Texas Fri, before
lifting back north as a warm front Sat ahead of yet another cold
front moving across Texas. The second front is expected to move
across the northwest Gulf, and reach from near the western
Florida panhandle to the SW Gulf Sun night. A warm front will
extend out ahead this front across the eastern Gulf.


A few showers linger between Jamaica and eastern Honduras along
the remnants of a dissipated frontal boundary that moved into the
northwest Caribbean earlier in the week. Farther west, a
few showers are active over the northeast Caribbean, with a
thunderstorm active briefly south of Puerto Rico earlier this
evening, related to a trough moving through the Virgin Islands
and Puerto Rico. Farther south, a couple of ship observations in
the ABC Islands indicate fresh to strong trade winds are active
along the coast of northwestern Venezuela and northeast Colombia.
Meanwhile, swell is still reaching 8 ft east of Windward Islands
as noted in a recent altimeter satellite pass.

The trough over the eastern Caribbean will gradually become
diffuse as it passes across eastern Hispaniola Thu. Ridging
north of the region will maintain fresh to strong winds off
Colombia through late in the week, expanding from the south
central into the southwest Caribbean late Wed through late Fri.
These winds then diminish Sat afternoon, before pulsing back up
to fresh to strong Sat night into Sun.


A frontal boundary from 31N65W to the southern Bahamas and
Turks/Caicos Islands is starting to stall and weaken. Showers
and isolated thunderstorms remain active along the boundary from
24N to 28N. Seas are still reaching 8 to 10 ft north of 26N west
of front to 75W in NW swell. Seas in open waters are 4 to 6 ft
elsewhere except 2 to 4 ft off northeast Florida.

The front start to dissipate later today and the remains of the
front will lift northward through Fri ahead of the next cold
front. This next cold front will move off the northeast Florida
coast late Thu, reach from Bermuda to south Florida by late Fri,
before stalling from 25N65W to the Straits of Florida by late
Sat. The gradient will tighten between the front and high pres
that builds eastward north of 28N on Sat night into Sun allowing
for east winds to increase over much of the waters west of 70W.

Farther east, a 1028 mb high is over the central Atlantic near
33N44W. The tail-end of a cold front is over the east Atlantic
from 32N22W to 29N30W. A large area of NW swell with wave heights
of 8-15 ft will accompany this front covering a large portion of
the area north of 20N and east of 45W Wed through Friday. Seas
will gradually decay to below 8 ft Saturday into Sunday.

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