[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102318
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
618 PM EST Sat Feb 10 2018

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
2330 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: A tight surface pressure gradient
between the strong surface ridge over the north Atlantic Ocean
and lower pressures over northwestern South America will continue
to support gale-force winds pulsing near the coast of Colombia
through the next week, mainly at night. Please read the latest
NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic waters along the 06N10W and
reaches to 01N17W. The intertropical convergence zone continues
from that point to 05S35W. Scattered showers are observed along
the monsoon trough between 10W-15W. Scattered showers are also
noted along the ITCZ west of 30W to the coast of Brazil.

...DISCUSSION...

GULF OF MEXICO...

A ridge extending from the western Atlantic through the central
Gulf supports moderate southeast winds, except for moderate to
fresh east winds over the Straits of Florida. Scattered showers
and a few thunderstorms are active over the far northern Gulf
along the coast of Louisiana. The moist southerly flow is
allowing dense fog over mainly the coastal water across the
northwest Gulf, with 3 NM visibilities over offshore areas of the
northwest Gulf. No fog is currently observed elsewhere, but may
develop over the eastern Gulf early Sun.

The fog will lift across the northwest Gulf by early Sun
afternoon as a cold front moves into the region off the Texas
coast. The front will reach a position from southeast Louisiana
to near Brownsville, Texas by Sun evening, and from the western
Florida Panhandle to the central Bay of Campeche by Mon evening,
where it will stall and weaken. Fresh to strong northerly winds
and building seas to 8 ft will follow the front Sun night and
Mon. Looking ahead, winds and seas will diminish into Tue as a
ridge develops over the southeast United States. This pattern will
support fresh east winds by mid week.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for details about the
gale-force wind conditions expected near the coast of Colombia.

GOES-16 water vapor imagery continues to show stable, dry air
across most of the basin, which is supporting generally fair
weather conditions. The exception is related to a weak upper
trough over the Bahamas supporting a weak surface trough over
eastern Cuba and scattered showers and a few thunderstorms over
the southern coast of Cuba south of Camaguey, and another area of
showers near Negril, in western Jamaica. Strong high pressure
north of the area continues to support fresh to strong trade winds
across the eastern and central Caribbean, as noted in recent buoy
observations and scatterometer satellite data. Seas are reaching
8 to 12 ft, highest of Colombia in the area of developing gales.

The areal extent of the strong trade winds and associated seas
will spread westward through mid week, including the Windward
Passage and lee of Cuba. Otherwise, little change is expected.

ATLANTIC OCEAN...

Broad surface ridging anchored N of the area by a 1042 mb high in
the north central Atlantic and a 1039 mb high southwest of the
Azores extends across the basin. The ridge is supporting moderate
to fresh east to southeast flow over the western Atlantic west of
65W, with occasional fresh to strong trade winds south of 22N with
8 to 9 ft seas. A few showers are ongoing east of the central and
northern Bahamas, related to surface trough reaching form the
central Bahamas to eastern Cuba. A cold front will move off the
northeast Florida coast by late Tue, followed by fresh northerly
flow and building seas north of the Bahamas, then diminish through
mid week as the front stalls and dissipates.

Farther east over the central Atlantic, a nearly stationary upper
low is centered near 25N45W, supporting a surface trough south of
ridge along 45W from 20N to 28N. Scattered showers and
thunderstorms are noted within 90 NM either side of the trough
axis. The surface trough weakens the gradient enough to support
mainly moderate to fresh trade wind flow across the central
tropical Atlantic, but seas remain 8 to 10 ft in easterly swell.

Over the eastern Atlantic, fresh to strong northeast winds persist
north of 10N. The long duration and fetch of these strong winds
support fully developed seas of 8 to 11 ft. Jet dynamics aloft on
the southeast side of the upper low near 25N45W is supporting a
broad area of multi-level cloudiness probably along with a few
embedded showers from the coast of Guyana to the Cabo Verde
Islands.

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

$$

ERA/Christensen
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