Tropical Weather Discussion
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AXNT20 KNHC 171030

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
630 AM EDT Tue Apr 17 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
1000 UTC.


The monsoon trough extends from the coast of Africa near 06N10W
to 03N20W. The ITCZ continues from 03N20W to 02N30W to 03S40W.
Scattered moderate convection within 60 nm either side of monsoon
trough and ITCZ axes east of 25W.



1023 mb high pressure centered over the north central Gulf near
26.5N 90W is maintaining generally fair weather across the basin.
Moderate to fresh SE return flow is commencing over the northwest
Gulf between the high pressure and lower pressure over the
southern Plains, with seas building to 7 ft. Seas are 4 to 6 ft
over the southeast Gulf mainly due to linger NW swell following
yesterday`s frontal passage. The front left the
Gulf fairly dry, and no shower or thunderstorm activity is noted.
Visibility remains unrestricted across the Gulf.

The high pressure over the north central Gulf will shift east and
weaken through mid week ahead of cold front moving into the
northern Gulf Thu. The front will stall from southwest Florida to
south Texas Fri, before lifting north as a warm front Sat ahead of
another cold front over Texas approaching the northwest Gulf.


A dissipating stationary front is across the northwest Caribbean
from central Cuba to eastern Honduras. Some showers are noted
near the front, but are steadily diminishing in intensity and
areal extent. Fresh to strong northerly winds are active west of
the front, especially in the Gulf of Honduras where an earlier
altimeter satellite pass showed seas reaching 8 ft. Farther
south, a recent scatterometer satellite pass indicated strong
trade winds off the coast of Colombia.

Farther east, a vigorous upper trough moving across the eastern
Caribbean into the tropical Atlantic was supporting areas of
heavy showers and a few thunderstorms across the northern Windward
Islands late yesterday. An earlier scatterometer satellite pass
indicated fresh to strong easterly winds between Saint Vincent and
Martinique. Media sources on Martinique reported small hail
Monday in scattered thunderstorms from this disturbance. An
associated surface trough west of the Lesser Antilles and
diffluent flow aloft from the upper trough is continuing to
enhance clouds and showers in the Windward Islands. Gusty winds
and higher seas are possible near these thunderstorms through
early morning as the supporting upper trough shifts slowly east of
the area. Meanwhile, NE to E swell to 8 ft is still present in
the tropical Atlantic waters east of the Windward Islands.

The front dissipate through late Tue. The trough over the eastern
Caribbean will move through Hispaniola and dissipate through mid
week. A building ridge north of the region will the area of winds
and seas off Colombia to expand across the south central Caribbean into
the southwest Caribbean late Wed through late Fri, while
maintaining pulses of strong winds off Colombia through late Sat.


A cold front reaches from 31N70W to eastern Cuba. Scattered
showers and a few thunderstorms are active along the frontal
boundary. Strong SW winds are noted north of 29N within 120 nm
east of the front. Strong NW winds are also noted in a recent
scatterometer satellite pass north of 30N off northeast Florida,
related a reinforcing front moving off the Carolina coast toward
the front. Seas are 8 to 11 ft north of 30N west of 68W. Elsewhere
over open waters, seas are 5 to 7 ft.

The fronts will merge this morning and continue east. The merged front
will will slow as it reaches from Bermuda to eastern Cuba late
today, before stalling and weakening from 28N65W to central Cuba
late Wed, then dissipating Thu as it lifts northward. Another 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.

Farther east, ridging north of 22N between 45W and 65W will dissipate
today ahead of a cold front approaching the region from the north
central Atlantic. The front will slide east of 35W Wed,
accompanied by a large area of NW swell with wave heights of 8-15
ft covering a large portion of the area north of 20N and east of
45W Wed through Fri, before starting to decay below 8 ft through

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