[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070527
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1227 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 0000 UTC surface analysis and satellite imagery through
0400 UTC.

...SPECIAL FEATURES...

...Atlantic Gale Warning...

Strong high pressure of 1039 mb building SE toward the U.S.
Atlantic coast will support strong to minimal gale force NE winds
through the Windward Passage, and also S of 23N just W of a
stationary front that currently extends from 31N54W to 25N66W to
20N74W later this morning through early Monday morning. 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 gale force winds 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. Widely scattered moderate convection is
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 1039 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. Also,
low level cloud cover is noted over the SW Gulf. 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 this morning. 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 09.5N81W. 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 66W. 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 pres
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 a weak 1016 mb low near 25N66W to 20N74W. 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 33N35W 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

$$
Latto
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