Tropical Weather Discussion
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AXNT20 KNHC 220540

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
139 AM EDT Tue May 22 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
0515 UTC.


A broad surface low pressure area has formed over the northwestern
Caribbean Sea a couple of hundred miles east of the coast of Belize.
This low and an upper-level trough are producing widespread
cloudiness and showers extending from the northwestern Caribbean
Sea across Cuba and the Florida peninsula.  While environmental
conditions are expected to be unfavorable for development during
the next couple of days, some gradual subtropical or tropical
development is possible later this week while the system moves
slowly northward into the central or eastern Gulf of Mexico.
Regardless of development, locally heavy rainfall is possible
across western Cuba and much of Florida during the next several
days.  For more information on the heavy rain threat, please see
products issued by your local weather office. There is a very low
chance for tropical storm formation within 48 hours.


A tropical wave is along 35W S of 10N, moving W at 10-15 kt. This
wave is embedded in a sharp 700 mb trough. Scattered moderate
convection is from 00N-03N between 31W-35W.

A tropical wave is over the E Caribbean Sea along 63W S of 16N,
moving W at 10-15 kt. This wave is also embedded in a 700 mb
trough and has a poleward surge of moisture associated with it.
This wave is expected to weaken over the next 24-36 hours and
be ill defined thereafter. Scattered showers are confined to NE


The monsoon trough passes through the coastal sections of Sierra
Leone near 08N12W to 04N15W. The ITCZ continues from 04N15W to
02N34W. The ITCZ continues W of the tropical wave near 01N36W and
extends to the coast of Brazil near 00N50W. Besides the convection
mentioned in the tropical wave section, widely scattered moderate
convection is from 01N-06N between 11W-29W.



A 1014 mb low is centered over the Florida Panhandle near 30N87W.
A surface trough extends S from the low to the SE Gulf of Mexico
near 23N85W. Radar imagery shows scattered moderate convection
over S Florida, the Straits of Florida , and the SE Gulf, S of 26N
and E of 85W. Elsewhere, scattered showers remain along the
Louisiana and Texas coasts.

In the upper levels, a sharp upper level ridge is over the NW
Gulf with axis along 94W. More importantly, a sharp upper level
trough is over the E Gulf with axis along 86W. Upper level
diffluence E of the trough axis is enhancing the convection over
the SE Gulf.

A surface ridge over the NW Gulf will shift east through mid week
ahead of a developing low pressure area expected to emerge off
the coast of Yucatan Thu. The low pressure will continue to move
northward into the north central Gulf through Sat, bringing fresh
to strong winds and building seas to the eastern Gulf.


Please read the Special Features section for more details about
the upper level trough and related surface weather features over
the NW Caribbean Sea.

Scattered moderate to isolated strong convection is over the W
Caribbean from 13N-22N between 76W-85W. Patches of scattered
moderate convection is inland over Central America from the
Yucatan Peninsula to Panama. Elsewhere, the monsoon trough is
along 09N from Costa Rica to N Colombia. Scattered moderate
convection is from 08N-13N between 73W-86W.

In the upper levels, an upper level trough is over the NW
Caribbean. An upper level ridge is over the central Caribbean. A
large upper level trough is over the E Caribbean with strong
subsidence over the NE Caribbean.

Atlantic Ocean high pressure will maintain fresh to locally
strong trades in the central Caribbean Sea through Friday night.
Strong winds, and sea heights to 9 feet, will affect the NW coast
of Colombia. A surface trough will linger in the NW Caribbean Sea
through Thursday. It is possible that a low pressure center may
form along the surface trough in the Gulf of Honduras on Tuesday,
and then move northward into the Gulf of Mexico on Friday. Fresh
to strong winds will develop in the central and western Caribbean
Sea from Thursday through Friday night.


A 1026 mb high is centered over the central Atlantic near 31N53W
producing mostly fair weather.

Upper level diffluence is over the W Atlantic W of 74W to include
central Cuba, the Bahamas, and the Florida coast. Scattered
showers are over the area. A large upper level low is centered
near 22N58W. Scattered moderate convection is from 17N-22N between

A surface E to W ridge along 30N will support gentle to moderate
SE winds north of 22N and moderate to fresh trade winds south of
22N into mid week, with winds pulsing to strong off Haiti mainly
at night. Winds and seas will diminish slightly into Fri as the
ridge shifts east. SE winds may increase near Cay Sal Bank
starting Fri as low pressure moves northward through the Gulf of

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