[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091743
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1243 PM EST MON JAN 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

ATLC GALE WARNING...

A cold front extends from 31N58W to Hispaniola into the Caribbean
Sea. The most recent scatterometer pass continues to indicate
northerly gale force behind the front, particularly S of 25N,
including the SE Bahamas and the Turks and Caicos Islands. A ship
observation near 21N68W also confirmed the presence of the gale
force winds. Sea heights are 14-15 ft behind the front. Winds are
forecast to diminish below gale force late today. Fresh to strong
northerly winds are expected to persist behind the front during
the next 24-48 hours. The front is forecast to reach a position
from 31N56W to Dominican Republic by early Tuesday morning. See
latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/
FZNT02KNHC for more details.

CARIBBEAN GALE WARNING...

The above mentioned cold front continues SW from Hispaniola to
near Cabo Gracias a Dios, Nicaragua. Fresh to strong NE winds
follow the front due a tight pressure gradient between the front
and a very strong high pressure center of 1044 mb over the
Carolinas. Winds are already reaching near gale force across the
Windward Passage and downstream between Haiti and Jamaica. As of
1500 UTC, the front has stalled from Hispaniola to NE Nicaragua
and is lifting north across the coast of Honduras into the Gulf of
Honduras. Strong to near gale northerly winds and building seas
will continue to spread eastward across the western and central
Caribbean in the wake of the front, with a narrow swath of
minimal gale force winds persisting downstream of the Windward
Passage and across the waters between Haiti and Jamaica through
Tuesday morning. See latest NWS High Seas Forecast under
AWIPS/WMO headers MIAHSFAT2/FZNT02KNHC for more details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends from the African coast near 05N10W to
04N12W. The Intertropical Convergence Zone axis continues from
04N12W to 02N25W to the coast of South America near 03S45W.
Scattered moderate convection is from 02N-05N between 07W-12W, and
within 120 nm N of ITCZ axis between 19N-21N.

...DISCUSSION...

GULF OF MEXICO...

A 1044 mb high pressure centered over the Carolinas extends a
ridge across most of the Gulf region. Under the influence of the
ridge, fresh to strong NE winds are observed across the SE Gulf,
including the Straits of Florida and the Yucatan Channel. Moderate
to fresh NE winds are noted over the NE Gulf while southerly
return flow is beginning to establish over the western Gulf.
Broken cold air stratocumulus clouds cover much of the region. The
high pressure will slide eastward through Wednesday, with the SE
return flow spreading eastward across the western half of the Gulf
on Tuesday. A ridge will continue to dominate the area through at
least Thursday. In the upper levels, a W-NW flow is seen, with
water vapor imagery showing strong subsidence and implied dry
airmass over the entire Gulf.

CARIBBEAN SEA...

A cold front extends from Hispaniola to NE Nicaragua. See Special
Features section for details. Isolated to scattered showers are
associated with the frontal boundary. Strong high pressure north
of the area combined with the Colombian/Panamanian low supports
fresh to strong trades across the south-central Caribbean, with
winds of 25-30 kt near the coast of Colombia. Moderate to locally
fresh trade winds are noted elsewhere ahead of the front. Cold air
stratocumulus clouds are west of the front while shallow moisture
embedded in the trade wind flow will continue to move across the
eastern and central Caribbean producing isolated to scattered
passing showers. Expect fresh to strong NE-E winds across most of
west and central Caribbean on Tuesday, including also the Windward
Passage and the Mona Passage as well as the regional Caribbean waters
south of Dominican Republic. In the upper levels, a ridge is over
the E Caribbean with axis along 62W. SW flow, on the west side of
the ridge, is advecting mid-upper level moisture from the EPAC
across the east and central Caribbean Sea.

...HISPANIOLA...

A cold front is over Hispaniola generating some shower activity,
isolated thunderstorm and gusty winds. Strong to near gale force
winds are behind the front. These winds are mainly affecting the
north coast of Hispaniola and the Windward Passage based on a
recent ASCAT pass. The cold front will shift eastward on Tuesday
moving away from the island. However, the NE winds behind the
front will bring some clouds with embedded light passing showers.

ATLANTIC OCEAN...

A cold front enters the forecast area near 31N58W and extends SW
to Hispaniola into the Caribbean Sea. See Special Features
section for details. Visible satellite imagery shows a well
defined 210 nm wide-band of cloudiness with embedded showers and
scattered thunderstorms in association with this front. Cold air
stratocumulus clouds are behind the frontal boundary. The strong
northerly winds behind the front are transporting these clouds
toward the Bahamas and Cuba. Farther east, there is a weak low
pressure of 1014 mb near 28N32W generating some shower activity.
A trough extends from the low center to near 20N34W. The low is a
reflection of an upper-level low and is forecast to move SW to a
position near 24N41W in about 24 hours. Fresh to strong winds are
between the low center and a high pressure centered north of the
Azores. This system extends a ridge SW to near 22N58W. The ridge
is over the central Atlantic between the low center and the cold
front.

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

$$
GR

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