Tropical Weather Discussion
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AXNT20 KNHC 180004

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
704 PM EST Wed Jan 17 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
0000 UTC.


...Gulf of Mexico Gale Warning...

A strong cold front continues to move across the Gulf region. The
front extends from a 1020 mb low pressure centered over the South
Carolina`s coast and continues southwest across northern Florida
into the Gulf of Mexico to near 28N83W to 24N89W to 19N93W. Gale
force winds are occurring west of the front mainly south of 26N
based on the latest scatterometer pass. A recent altimeter pass
indicates seas of 16-18 ft within the area of gale force winds.
The front will continue moving south of the basin tonight. Gale
force winds are expected west of the front along the coast of
Mexico near Veracruz through tonight. Fresh to strong northerly
winds are also expected elsewhere behind the front through
tonight. High pressure behind the front will slowly shift eastward
along the US Gulf coast through Friday. Please read the latest
NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC, and the latest NHC Offshore Waters Forecast,
MIAOFFNT4/FZNT24 KNHC, for more details.

...Atlantic Gale Warning...

The low pressure currently located over the South Carolina`s coast
will move eastward into the western Atlantic Ocean while
deepening. This will induce an area of gale-force winds north of
30N on Thursday behind the strong cold front that is currently
moving off the northern Florida coast. The front will extend from
31N69W to eastern Cuba on Thursday, then weaken southeast of the
Bahamas from 24N65W to the Windward Passage on Friday. Strong
high pressure behind the front will bring strong winds and high
seas northeast of the Bahamas through Thursday night. Please read
the latest NHC High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC, and the latest NHC Offshore Waters
Forecast, MIAOFFNT3/FZNT23 KNHC, for more details.


The monsoon trough enters the Atlantic Ocean through Sierra Leone,
Africa and continues to 01N21W. The ITCZ extends from 01N21W to
02N40W to the Equator at 50W. Scattered moderate convection is
observed within about 120 nm N of the ITCZ between 30W-40W.
Similar convection is from 03N-04.5N between 42W-47W.



A strong cold front is moving across the Gulf region. See the
Special Features section for more details. A band of multi-layer
clouds with embedded showers is associated with the front followed
by cold air stratocumulus clouds forming parallel to the wind.
Cold air has penetrated into the eastern slopes of the Sierra
Mountains as depicted by a rather uniform stratus cover and
stationary front is analyzed along the leading edge of this
cloudiness. A ridge dominates the remainder of the Gulf waters.
Fresh to locally strong southerly flow will set- up across the
western Gulf by Fri, and persist on Saturday ahead on the next
cold front forecast to reach the Texas coast Sun night.


A dissipating stationary front remains across the basin extending
from eastern Cuba to near 17N80W. Abundant cloudiness with
embedded showers and tstms are noted over the NW Caribbean and a
surface trough is analyzed there extending from 21N86W to 15N82W.
According to the Galvez-Davison Index (GDI), there is a potential
for widespread shallow convection across the NW Caribbean and
parts of Nicaragua and Honduras today. Abundant moisture will
persist over this area through Thursday based on the GFS model.
Patches of low-level moisture carried by the trade wind flow are
seen across the remainder of the Caribbean Sea. Moderate to fresh
NE winds are seen in the lee of Cuba, and within about 60 nm of
the coast of Nicaragua. Fresh to strong winds are near the coast
of Colombia. The cold front currently moving across the Gulf of
Mexico will reach the NW Caribbean tonight, then extend from
central Cuba to Honduras on Thursday. Fresh to strong winds and
widespread showers are expected behind the front through Thursday
night. Strong trade winds will pulse near the coast of Colombia
coast Fri night and then expand across much of the central
Caribbean over the weekend as high pressure builds N of area.


Relatively dry weather with partly cloudy skies and isolated
showers will prevail for the next day or so over the island due
to the influence of a ridge. Computer models show increasing
moisture across Hispaniola toward the end of the work-week as a
cold front approaches from the west. Fresh NE winds are expected
across the Windward Passage Thursday through Saturday night as
high pressure builds across the western Atlantic in the wake of
the above mentioned front.


A weakening stationary front extending from 31N66W to eastern
Cuba will dissipate later tonight. A strong cold front is moving
off the Florida coast at this time and will be extending from
31N69W to eastern Cuba by Thursday, then weaken SE of the Bahamas
from 24N65W to the Windward Passage on Friday. See Special
Features section for more details. An upper-level low is
reflected at the surface as a trough that extends from 31N46W to
24N47W. Scattered showers and tstms are associated with this
low/trough covering mainly the waters N of 28N between 42W-45W. An
area of fresh to strong E-SE winds in noted E of the trough due
to the pressure gradient between the trough and a 1036 mb high
pressure located near the Azores at 40N25W. The trough will drift
westward over the next 24 hours. The strong high pressure near
Azores dominates most of the east and central Atlantic, and will
move little through Thursday.

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