[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071151
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
650 AM EST Sun Jan 7 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 0600 UTC surface analysis and satellite imagery through
1145 UTC.

...SPECIAL FEATURES...

...Atlantic Gale Warning...

Strong high pressure of 1038 mb building SE toward the U.S.
Atlantic coast supports strong to minimal gale-force NE winds
S of 23N just W of a stationary front that currently extends from
31N54W to 25N66W to 20N74W. Gale force winds will also develop
across the Windward Passage later today. Seas are forecast to
build to 11-12 ft within the area of gale-force winds. Fresh to
strong NE winds are expected to also affect the remainder of the
waters between the Bahamas and Cuba, and the Straits of Florida
with seas up to 13 ft outside the Bahamas. Conditions across the
region will improve Mon night through Tue as the high shifts E and
weakens. See the latest NWS High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

...Caribbean Gale Warning...

The aforementioned high pressure is also currently bringing
strong to minimal gale-force NE winds in the lee of east-central
Cuba, including the Cayman Islands as indicated by a recent
scatterometer pass. These conditions will continue through this
afternoon. The gale will then become confined to the Windward
Passage and approaches to the passage N of 16N and W to 76W
tonight. Seas are forecast to build to 10-12 ft near the Cayman
Islands this morning. See the 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 from the Africa coast
near 07N12W and continues to 01N24W. The Intertropical
Convergence Zone extends from 01N24W to the Equator at 42N to NE
Brazil near 02S46W. Scattered showers are within 120 nm S of the
monsoon trough, and within 240 nm N and 120 nm S of the ITCZ axis.


...DISCUSSION...

GULF OF MEXICO...

A ridge dominates the entire Gulf region anchored by a strong
high pressure of 1038 mb located over the Ohio Valley. The only
exceptions are a surface trough that has developed across the
central Gulf with an axis that extends from 28N91W to 22N90W, with
scattered showers within about 90 nm of the trough axis. The
pressure gradient between the high pressure to the north and lower
pressures over the Caribbean support fresh to strong NE winds
over the Straits of Florida. Fresh to strong E winds are also just
E of the surface trough. Mainly moderate to fresh NE to E winds
cover the reminder of the Gulf basin. The strong winds are expected
to prevail through today, expanding over the central Gulf and
becoming SE through this afternoon as the high pressure shifts E.
The next cold front is forecast to emerge off the Texas and
Louisiana coasts on Monday followed by mainly fresh northerly
winds and building seas of 5-6 ft. The front and associated winds
will weaken on Tuesday.

CARIBBEAN SEA...

A stationary front extends across the Windward Passage near 20N74W
to Jamaica to W Panama near 10N81W. Clusters of moderate
convection are noted along the the frontal boundary N of Jamaica,
and S of 11N. Abundant cloudiness with embedded showers are noted
across much of Cuba, Jamaica and the Cayman Islands in association
with this front. Patches of low-level moisture with embedded
showers are noted over the eastern Caribbean where a surface
trough is analyzed along 67W. Latest scatterometer data indicated
that gale-force winds are now occurring over the Lee of Cuba.
Fresh to strong winds are occurring elsewhere across the Windward
Passage, and across the south-central Caribbean near the coast of
Colombia. The stationary front will slowly weaken and drift W to
the S of 16N during the next few days. Strong high pressure
building SE toward the U.S. Atlantic coast will support gales
between Jamaica and lee of Cuba through this morning, and then the
Windward Passage and approaches tonight. Please see the Special
Features section for more details.

...HISPANIOLA...

The region is between a stationary front through the Windward
Passage and a surface trough approaching from the SE. The
moisture from these two features will support showers and
thunderstorms over the island through Monday. High pressure
building to the north will support 20 to 30 kt NE winds over the
northern coast of Haiti this afternoon and tonight.

ATLANTIC OCEAN...

A stationary front enters the area of discussion near 31N54W and
extends to 20N73W. Scattered moderate convection is noted within
360 nm NW of the front. The pressure gradient between strong high
pressure over the Ohio Valley and the stationary front supports 20
to 30 kt NE winds and seas of 7 to 10 ft in unprotected waters
south of 25N and west of the front. A 1030 mb high centered near
32N37W supports a broad area of fresh to strong easterly trades S
of 23N over the central and eastern Atlantic. The combination of
these winds and NW swell from a departing storm system over the
northern Atlantic supports seas of 8 to 14 ft over the majority of
the Atlantic discussion waters between the Cabo Verde Islands and
75W. Higher seas of 12 to 18 ft are occurring N of the Cabo Verde
Islands under strong northerly winds on the eastern periphery of
the Atlantic high pressure. The high over the Ohio Valley will
shift E through tonight and will increase the pressure gradient
just NW of the stationary front. This will result in gale-force
winds mainly S of 23N within about 150 nm W of the front,
including the Windward Passages and approaches later this morning
into early Monday morning. Please refer to the Special Features
section for more details.

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

$$

ASL/ERA
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