Tropical Weather Discussion
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000
AXNT20 KNHC 172354
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
754 PM EDT Wed May 17 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
2300 UTC.

...SPECIAL FEATURES...

A surface trough curves northeastward from the NE corner of
Nicaragua to Cuba near 21N78W to the SE Bahamas near 23N75W. The
surface trough is supported by a sharp mid- to upper-level trough
just to the NW. The upper-level trough extends SW from Southern
Florida to Central Honduras. Very strong upper-level divergence on
the SE side of the upper-level trough is helping to fuel
persistent deep convection over Eastern Jamaica and Haiti.
Furthermore, TPW satellite imagery shows this system has abundant
deep moisture to work with. The 1200 UTC Kingston, Jamaica
rawinsonde indicated precipitable water values of 2.3 inches.
Serious flooding has already been reported in Haiti and Jamaica.
Animated satellite imagery and model guidance both suggest this
system will only lift very slowly NE during the next 24 hours.
Heavy rainfall will thus remain possible over Eastern Cuba,
Jamaica and Hispaniola. Because of the slow movement of this
system and heavy rainfall already experienced by these areas, this
system will remain capable of producing life- threatening
flooding and mudslides. Please continue to closely monitor this
dangerous system by following the latest statements issued by
local authorities and emergency management services.

Please refer to the METEO-FRANCE High Seas Forecast, listed on
the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO-MARINE/BULLETIN/
GRANDLARGE/METAREA2. Gale-force winds are forecast during the
next 24 hours for the areas of AGADIR and CANARIAS. The Outlook
for the next 24 hours calls for local gale conditions to persist
in AGADIR. Winds in the CANARIAS area will decrease to near gale.

...TROPICAL WAVES...

A tropical wave extends from 10N37W to 00N38W, moving west around
10 kt. This wave is embedded in abundant moisture as noted in TPW
imagery. Scattered moderate and isolated strong convection is
evident from 03N to 06N between 33W and 38W.

A tropical wave extends from 10N58W to 01N59W, moving west at 10
to 15 knots. No significant convection is currently associated
with this wave.

A tropical wave extends from 14N77W to 03N77W, moving west at 10
to 15 kt. Isolated showers and thunderstorms associated with this
wave are affecting portions of northern Colombia and the adjacent
Caribbean waters.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends SW from the Guinea Coast of Africa
near 11N15W to 06N24W. The ITCZ continues from 06N24W to 04N36W,
then resumes west of a tropical wave near 04N40W to 04N48W to
07N56W. Isolated thunderstorms associated with the Monsoon Trough
are taking place within 60 nm either side of a line from 05N18W to
03N25W.

...DISCUSSION...

GULF OF MEXICO...

Mid- to upper-level ridging extends NE across the Gulf of Mexico
from the Bay of Campeche to the Florida Big Bend. At the surface,
a ridge extends SW from the western Atlantic across Central
Florida to the bay of Campeche. A lower pressure trough extends SE
over interior Mexico from Chihuahua to Chiapas. The pressure
gradient between the trough and ridge is generating moderate to
fresh ESE to SE winds across the Gulf. Little change in these
conditions is expected through Thursday night.

CARIBBEAN SEA...

A tropical wave is moving across the southern portion of the
basin in the vicinity of NW Colombia. Please refer to the tropical
waves section above for details. A deep-layer surface trough
extends from the western Caribbean across Cuba into the Western
Atlantic. Numerous moderate and scattered strong convection is
found from 15N to 20N between 72W and 77W. See the special
features section for more details on this system.

Satellite-derived wind data depicts fresh to strong trades across
all of the basin E of a line from the NE Yucatan near 20N87W to
Northern Colombia near 12N73W. Light to gentle winds are present
over the SW Caribbean. Slow movement of the deep-layer trough over
the Caribbean is expected to maintain a similar weather pattern
during the next 24 hours.

...HISPANIOLA...

Upper-level divergence aloft remains in place over the island.
This is fueling scattered to numerous showers and thunderstorms
over SW Haiti. This convection has remained very persistent during
the past 24 hours over portions of western Hispaniola. More
rainfall is likely through the next 24 hours. Consequently, the
risk of serious flooding and mudslides continues. Please pay
attention to advisories and bulletins from local meteorology
offices and other governmental agencies.

ATLANTIC OCEAN...

A 1025 mb surface high is centered near 33N67W. Its associated
ridge crosses the western Atlantic from 32N54W to 30N81W. To the
east, a weakening cold front extends SW from 32N51W to 28N56W to
26N62W. Scattered moderate convection associated with the front is
affecting the waters north of 25N and E of the front to 42W. Two
tropical waves are moving across the basin. Refer to the tropical
waves section above for details.

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

$$
McElroy



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