Tropical Weather Discussion
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AXNT20 KNHC 171717

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1217 PM EST Sun Dec 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.


...Caribbean Sea Gale Warning...

Strong surface high pressure centered off the coast of South
Carolina and the west Atlantic tightens the pressure gradient in
the south- central Caribbean, thus supporting gale-force winds
along the northwest portion of the Colombian coast. These winds
will pulse every night through early next week as the ridge builds
over southwest Atlantic waters. Sea heights will range from 8 to
15 feet in the area of strongest winds. Please read the latest NHC
High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC
for more details.


The monsoon trough passes through the coast of West Africa near
07N12W to 06N26W. The ITCZ continues from 06N26W to 07N45W. No
significant convection is observed along these boundaries at this



A mid level short-wave trough extending from northern Texas to a
base over the northwest Gulf waters supports a 1015 mb low
centered over southwest Louisiana. A cold front extends from the
low to near Tampico, Mexico while a warm front extends from the
low to the east to 31N87W to 29N84W. Scattered moderate convection
is observed north of 28N between 90W-93W. Fresh to strong winds
are in the vicinity of the low due to a tight pressure gradient
between the low and high pressure over the southeast CONUS. The
front will weaken gradually today and transition into a surface
trough as the low moves inland over through early Monday.


Gale-force winds will continue to pulse at night in the south-
central Caribbean as a strong high pressure builds in the west
Atlantic waters. Please refer to the Special Features section
above for details. Fair weather prevails across the remainder of
the basin supported by a broad mid to upper-level high and very
dry air aloft. Little change is expected through the next 24-48


A broad mid to upper-level high is covering the Caribbean and
very dry air aloft support stable conditions across the island.
Similar conditions are forecast through Monday. Fresh to strong
easterly winds will continue across the Windward Passage through


A broad mid to upper-level trough over the west Atlantic supports
a frontal system, analyzed as a cold front from 31N50W to 25N63W,
then as a stationary front from that point to 24N79W. No
significant convection is associated with these frontal boundaries.
Strong high pressure is building west of the fronts and is
forecast to prevail over the area through the mid-week.
To the east, the Azores high continues to extend across the
eastern Atlantic waters with fair weather.

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