Tropical Weather Discussion
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000
AXNT20 KNHC 182358
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
758 PM EDT Sun Jun 18 2017

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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Potential Tropical Cyclone Two has developed, as of 2100 UTC. Its
center is located near 7.5N/50.4W, moving west at 20 kt. Maximum
winds are 30 kt with gusts up to 40 kt. This system is expected to
continue moving west across the southeast Caribbean while
intensifying through the next 48 hours, then weakening by
Wednesday. Please see latest full NHC Potential Tropical Cyclone
Forecast/Advisory and Intermediate Public Forecast/Advisory under
AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC and MIATCPAT2/WTNT32 KNHC
for more details.

A broad area of low pressure in the northwestern Caribbean Sea is
centered by a 1006 mb low near 19N87W. This system is generating
clusters of heavy showers with embedded thunderstorms north of 12N
and west of 78W affecting western Cuba, western Jamaica, Cayman
Islands, the Yucatan Peninsula and Central America. Gale-force
southeast winds are N of 19N between 81W and 83W with seas of 9
to 11 ft. Fresh to near-gale force winds are elsewhere north of
16N between 78W and 84W with seas to 10 ft. These conditions are
forecast to continue through Monday morning. Gradual development
of this system is expected while it moves slowly northwestward
across the Yucatan Peninsula later today and over the southern or
central Gulf of Mexico on Monday and Tuesday, where a tropical or
subtropical cyclone is likely to form. Regardless of development,
heavy rains are expected over portions of Central America, the
Yucatan Peninsula, Jamaica, the Cayman Islands, and western Cuba
during the next several days. The chance of formation into a
tropical cyclone during the next two days is high. Please read
the latest NHC Tropical Weather Outlook under AWIPS/WMO headers
MIATWOAT/ABNT20 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is in the east Atlantic associated with a 1010 mb
low near 08N25W. Its axis extends from 13N25W to the low to
02N26W, moving west at 20 kt. CIRA LPW imagery shows a moderate
moist environment within this wave with some patches of dryness
associated with Saharan air and dust intrusion. Upper-level
divergence supports isolated showers within 50 nm around the low
center.

A tropical wave is in the central Atlantic with axis extending
from 11N35W to 03N36W, moving west at 10-15 kt within the last 24
hours. Extensive intrusion of Saharan dry air and dust is
observed in this wave`s environment which is limiting the
convection to isolated showers within 120 nm either side of the
axis from 05N to 08N.

The tropical wave and low along 49W is now the Potential Tropical
Cyclone Two. This system is described in the Special Features
Section above.

A tropical wave is located within 100 nm east of the Lesser
Antilles. Its axis extends from 19N58W to 09N59W, moving west at
15-20 kt within the last 24 hours. Shallow moisture and a mid-
level divergent environment ahead of the wave support scattered
showers and thunderstorms south of 18N between 59W and 64W.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough extends from the coast of west Africa near
14N17W to a 1010 mb low near 09N25W to 06N31W. The ITCZ extends
from 04N36W to 05N43W, then resumes W of a tropical wave near
05N52W to 06N58W. Three tropical waves are embedded within the
Monsoon trough/ITCZ. See tropical waves and special features
sections for information about convection.

...DISCUSSION...

GULF OF MEXICO...

Broad surface high press covering great portions of the Atlantic
waters extends its ridge axis across the Florida peninsula and the
northern Gulf waters. With this, a gentle to moderate southeast
flow extends across the basin, except for the southeast Gulf. In
this area, the Special Feature low centered over the northwest
Caribbean supports moderate to fresh easterly winds. Please refer
to the section above for more details about the low. Scattered
showers associated with the rainbands of this systems are already
affecting the Florida straits and the Yucatan channel.

CARIBBEAN SEA...

The major concern in the basin is a broad area of low pressure
located over the northwest Caribbean, which is generating
numerous heavy showers and strong to gale-force winds. Gradual
development of this system is expected while it moves slowly
northwestward across the Yucatan Peninsula later today and over
the southern or central Gulf of Mexico on Monday and Tuesday,
where a tropical or subtropical cyclone is likely to form. See the
Special Features section for more details. Scattered showers and
thunderstorms are prevailing over the far east Caribbean ahead of
a tropical wave that extends along 59W. See the Tropical Waves
section for further details. A surface trough off the coast of
Panama is supporting scattered showers and thunderstorms south of
14N between 75W and 79W.

...HISPANIOLA...

Isolated showers are across the island being influenced by the
broad area of low pressure in the NW Caribbean. Showers are
forecast to continue through the evening hours.

ATLANTIC OCEAN...

Three tropical waves and a potential tropical cyclone are moving
westward between the coast of Africa and the Lesser Antilles.
Please refer to the sections above for details. A diffluent flow
aloft combined with the broad low centered over the northwest
Caribbean are enhancing isolated showers across the Florida
Straits and the Bahamas mainly west of 77W. Otherwise, a broad
high pressure covers the Atlantic from the Azores to the Florida
Peninsula, with a 1024 mb high pressure near 29N48W.

For additional information please visit
http://www.hurricanes.gov/marine

$$

ERA




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