Tropical Weather Discussion
Issued by NWS
AXNT20 KNHC 212347
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
746 PM EDT Fri Apr 21 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
A tight pressure gradient between a broad low pressure system
centered near 33N48W and an area of high pressure to the west is
supporting gale-force winds north of 29N between 44W and 52W. Seas
in this area will range between 13 to 19 ft through the gale
event. These conditions will continue through tonight, ending by
1200 UTC Saturday morning. Please see the latest High Seas
Forecast product under the WMO header FZNT02 KNHC and under the
AWIPS header MIAHSFAT2 for further details.
The Monsoon Trough extends across the western Africa coast from
08N13W to 04N17W. The Intertropical Convergence Zone continues
from 04N17W to 00N28W to the coast of Brazil near 02S45W.
Widely scattered moderate convection is south of 05N between 16W
and 40W and south of 08N east of 16W.
GULF OF MEXICO...
High pressure extends across the western Atlantic to the
northeastern Gulf, supporting gentle to moderate southeast winds
over the northern Gulf, moderate easterly winds over the southeast
Gulf, and gentle winds over the southwestern Gulf. The
combination of an upper trough and a surface trough extending from
24N86W southward across the Yucatan Channel supports numerous
showers and scattered thunderstorms south of 25.5N and east of
89W. Over the next 24 hours a broad area of low pressure may
develop over the southeastern Gulf as moisture spreads north and
east across southern Florida.
A surface trough extends from the southeastern Gulf to the
Yucatan Channel near 22N86W to 19N83W to 19N79W. The combination
of this surface trough and an upper level trough over the area
supports numerous showers and scattered thunderstorms north of a
line from 21N87W to 14N74W. Fresh easterly winds are northeast of
the trough axis. Light to gentle winds are across the western
Caribbean south of the trough axis. High pressure north of the
eastern Caribbean supports mainly moderate trade winds over the
remainder of the Caribbean. Over the next 24 hours the showers
and thunderstorms over the northwestern Caribbean will gradually
shift north and east as a broad area of low pressure develops over
the Gulf of Mexico, and the upper trough lifts northeast. Little
change is expected elsewhere.
Increasing moisture from an upper trough to the west of the area
is spreading showers and isolated thunderstorms across the island
this evening. Expect the moisture to continue to spread across the
island through the weekend with showers and thunderstorms likely
Saturday and Sunday.
Gale force winds are south of a 989 mb surface low located near
34N48W. See the Special Features section above for further
details. A surface ridge extends across the western Atlantic
anchored by a 1021 mb high centered near 29N69W. Showers are
beginning to spread across the waters southeast of the Bahamas to
the east of an upper trough. To the east, a cold front enters the
area from 31N37W to 22N47W. A surface trough is just west of the
front extending from 31N42W to 24N40W. Isolated moderate
convection and thunderstorms are from 25N to 31N east of the
trough to 32W. High pressure of 1019 mb centered near 28N21W
dominates the remainder of the eastern Atlantic. Over the next 24
hours showers and thunderstorms will increase across the Bahamas.
The gale force winds will end Saturday morning. Showers and
thunderstorms will continue east of the front over the central
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