[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 092328
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
628 PM EST Thu Feb 9 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
2315 UTC.

...SPECIAL FEATURES...

...CARIBBEAN GALE WARNING...

A gale warning remains in effect within about 90 nm of the coast
of Colombia. The pressure gradient between high pressure north of
the region and the Colombian/Panamanian low will continue to
support fresh to strong trades over the south-central Caribbean
during the next several days. Winds will pulse to gale force
within about 90 nm of the coast of Colombia during the overnight
and early morning hours through Sunday night. Latest wave guidance
shows seas building to 12-13 ft over the region with the strongest
winds. Strong to near gale force winds will continue over the
south-central Caribbean through Monday. See latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough enters the Atlantic Ocean near the Sierra
Leone/Liberia border to 04N20W. The ITCZ continues from 04N20W to
the Equator at 29W. Scattered moderate to isolated strong convection
is from 02N-04N between 08W-14W. Scattered moderate convection is
noted from 02N-04N between 14W-17W, and from 00N-03N between 21W-
26W.

...DISCUSSION...

...GULF OF MEXICO...

A cold front is moving across the Gulf of Mexico and extends from
SW Florida to 25N90W to 23N96W to near Veracruz Mexico. Tampico
Mexico reported gusty winds to 30 kt with the frontal passage.
Visible satellite imagery reveals a narrow band of cloudiness with
embedded showers in association with this front. Fresh to strong
northerly winds and seas of 6-7 ft follow the front. The west
part of the front will stall and weaken while the east part will
move across the Yucatan Channel and western Cuba by early Friday
morning. Winds behind the front are forecast to quickly veer to
the NE-E on Friday as high pressure in the wake of the front moves
east over the eastern United States. By late Friday, the high
pressure will move into the western Atlantic, extending a ridge
across the Gulf region. As a result, southerly return flow will
set up over the western Gulf. These winds will spread east across
the entire Gulf during the upcomimg weekend. Aloft, a long wave
trough located over the eastern United States crosses central
Florida and the Gulf to near Tampico Mexico. This trough supports
the aforementioned cold front.

...CARIBBEAN SEA...

A gale warning is in effect for the south-central Caribbean.
Please, see Special Feature section for details. Elsewhere,
scatterometer data provided observations of moderate to fresh
winds across the remainder of the east and central Caribean.
Gentle to moderate winds are noted over the NW Caribbean. A fast
moving cold front will reach western Cuba and the NW Caribbean by
early Friday morning with some shower activity, then the front
will move across the remainder of Cuba through late Friday while
gradually weaken across the Caribbean Sea. As high pressure, in
the wake of the front, moves eastward Friday through Saturday,
expect increasing northeasterly winds across Cuba and in the lee
of the island, including also the Windward Passage. Friday night
into Saturday, the GFS model suggests NE-E winds of 20-25 kt
between Las Bahamas and Cuba, south of Cuba, but mainy east of the
Isle of Youth (Isla de la Juventud) and across the Windward
Passage, where seas are forecast to build to near 8 ft. Shallow
moisture embedded in the trade wind flow will continue to move
across the region producing isolated to scattered passing showers.
Aloft, a westerly flow prevails across most of the basin with
moderate to strong upper level subsidence and implied dry air
mass. SW winds over northern South America are advecting some mid-
upper level moisture into the Caribbean Sea, including the ABC
Islands.

...HISPANIOLA...

Limited moisture due to the presence of a mid-upper level ridge
across the island will support only a few light showers tonight
and Friday. By late Friday, an approaching frontal boundary will
bring increasing cloudiness with scattered showers ang gusty
winds. The front is forecast to stall near the island during the
weekend while dissipating.

...ATLANTIC OCEAN...

A cold front enters the forecast region near 31N73W and continues
SW to across South Florida into the Gulf of Mexico. As previously
mentioned, visible satellite imagery reveals a narrow band of
cloudiness with embedded showers in association with this front.
Gale force winds were noted in the SW flow ahead of the front this
morning, but mainly north of 30N. The most recent ASCAT pass
provided observations of fresh to strong S-SW winds ahead of the
front, mainly north of 28N. Fresh to strong NW-N winds are also
expected behind the front, especially tonight into Friday
morning. The front will extend from near 31N54W across the SE
Bahamas and eastern Cuba by Friday evening, then will be near the
coast of Hispaniola by Friday night, and stall there during the
weekend. High pressure in the wake of the front will reach a
position near 32N76W by Friday evening. At that time, a belt of
fresh to strong NE-E winds is expected across much of the Bahamas,
the Turks and Caicos Islands, the waters between the Bahamas and
Cuba, and across the Straits of Florida.

E of the front, a strong high pressure of 1035 mb persists, with
the center located west of the Azores near 35N36W. This system
dominates the remainder of the forecast area. South of the ridge,
fresh to strong trade winds are noted, affecting the tropical
Atlantic between the Cabo Verde Islands and the Lesser Antilles.
The high pressure is forecast to reamain nearly stationary over
the next 24 hours, then will move southward and weaken on Saturday.


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

$$
GR
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