[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270859 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
1255 AM EST Sat Jan 27 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
0530 UTC.

...SPECIAL FEATURES...

Atlantic and Gulf of Mexico Gale Warning: The pressure gradient
has significantly tightened between a cold front that extends from
32N52W to 27N58W to 24N67W where it becomes a weakening
stationary front to 23N74W and to central Cuba and very strong
high pressure of 1040 mb centered around 110 nm E of northern N
Carolina. This tight pressure gradient has induced a large area of
near gale to minimal gale force NE to E winds over the waters
between the front and the Bahamas S of about 27N. Seas are in the
range of 12 to 16 ft with these winds, and are forecast to build
slightly higher during Saturday and Sun. As of late Fri night, a
new gale warning for frequent gusts for the waters W of the
Bahamas including the Straits of Florida and far eastern Gulf of
Mexico near 83W. Ascat and ship data from late last night
indicated that winds over the affected gale winds waters had
increased to near gale force with frequent gusts. Seas associated
with these gale force winds are in the 10 to 15 ft range. Strong
NE to E winds are elsewhere W of the front, including through
the Atlantic passages in the Bahamas. The latest model guidance
indicates that these winds will be slow in diminishing, and as per
the latest issued forecasts, these winds are forecast to lessen
to just below gale force on Sun afternoon over the waters E of the
Bahamas to the frontal system mentioned above. The gale force
winds W of the Bahamas that include the Straits of Florida and far
eastern Gulf of Mexico are forecast to diminish late on Sat to
strong NE to E winds. Seas will still be on the high range
possibly reaching up to 14 ft at that time. By late Sun, these
winds and seas diminished considerably. Please see the latest NHC
High Seas Forecast under AWIPS/WMO headers Misfit/FZNT02 KNHC for
more details on this event.

Caribbean Gale Warning: The combination of very strong high
pressure centered E of the mid-Atlantic states and lower pressure
over South America is bringing minimal gale force NE to E winds
near the coast of Colombia. These conditions will persist late at
night into the early morning hours through Mon. Please see the
latest NHC High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for more details on this event.

Far E Atlantic Gale Warning: Another very strong high pressure
system, this one of 1042 mb is centered well to the NE of the
Azores near 40N21W. The tight pressure gradient to its SE and S
is allowing for NE gale force winds that reach to strong gale
force over Meteo France marine zones of Agadir, Tarfaya and to
near gale force NE winds over Canarias except for strong gale
force winds over the eastern portion of that zone. NE winds are
reaching near gale force at times over zone Cap Blanc. These
conditions are expected through Sat evening. With the tight
gradient not expected to slacken in the short term, the gale
conditions for Agadir, Tarfaya and the near gale to gale for
Canarias are forecast to continue through Sun night. Please refer
to Meteo France Weather Bulletins for more information.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough axis extends from the coast of Africa at
06N10W to 05N14W where the latest scatterometer data indicates
the ITCZ begins and continues to 02N23W to 01N30W to just below
the Equator at 34W. Scattered strong convection is within 120 nm
S and 60 N of the axis between 32W-34W, and W of the axis S of 01N
between 34W-40W. Scattered moderate isolated strong convection is
within 120 nm S and 180 N of the axis between 12W-19W, and also
between 22W-29W. Scattered moderate convection is within 150 nm S
and 120 N of the axis between 25W- 28W. Scattered moderate
convection is within 120 nm either side of the axis between 10W-
12W.

...DISCUSSION...

GULF OF MEXICO...
Please see the SPECIAL FEATURES section above for details about
regarding the gale conditions in the far SE Gulf.

Strong surface high pressure centered near the northeastern
United States is supporting a large area of 20 to 25 kt winds over
much of the eastern and central Gulf of Mexico. The exception is
in the far SE Gulf and Straits of Florida where strong E winds are
gusting frequently to gale force. These winds are forecast to
diminish late on as the strong ridging over the eastern Gulf
begins to weaken some. Scattered showers and isolated
thunderstorms along with patches of rain are noted over much the
central portions of the gulf. This activity is lifting NNE.
Scattered showers and isolated thunderstorms are seen over the SW
Gulf just lifting to the N of a surface trough that extends from
21N96W to 19N92W. Strong winds are expected to continue over the
eastern Gulf today. On Sun, the pattern is expected to change as
low pressure is forecast to develop over the N central waters
along a warm front that will evolve from the SW surface trough as
it lifts northward. The low is forecast to quickly move across the
NE Gulf on Sun while pushing a cold front across the eastern gulf
waters through early on Mon. Expect widespread rain along with
scattered showers and isolated thunderstorms with system.

CARIBBEAN SEA...
Please see the SPECIAL FEATURES section above for details about
regarding the gale conditions near the coast of Colombia.

Fresh to strong trades are occurring across much of the region,
especially west of 70W due to the aforementioned strong high
pressure system to the N f the area. Scattered showers and
isolated thunderstorm are over the far western Caribbean Sea
close to the coasts of Honduras including the Gulf of Honduras.
Similar activity is over the waters between Jamaica and 82W.
Isolated showers and thunderstorms are noted over the Yucatan
Peninsula, northern and eastern Honduras and eastern Nicaragua.
Since the surface pattern is expected to change very little
through Sun, strong trade wind flow is forecast to continue during
the next couple of days. Expect increasing low-level moisture
along with scattered showers to impact the NE Caribbean and
islands in that location including Puerto Rico through Sun
night as a decaying frontal boundary over the central Atlantic
drops southward towards the NE Caribbean and strong to near gale
force NE winds advect the associated moisture and shower activity
towards that section of the Caribbean.

ATLANTIC OCEAN...Corrected
Please see the SPECIAL FEATURES section above for details about the
gale conditions over portions of the waters between the Bahamas and
a central Atlantic cold front.

A cold front enters the discussion area through 32N51W to 26N59W
to 24N66W where it becomes a weakening stationary front to across
the SE Bahamas and to central Cuba as of 03Z. Meanwhile, very
strong high pressure of 1040 mb is centered within about 110 nm E
of the northern coast of N Carolina. The resultant tight gradient
has increased the NE to E winds between the front and the Bahamas
to the ranges of near gale to minimal gale force and along with
large seas. These conditions are expected to continue into early
Sun afternoon. Scattered showers are within 60 nm either side of
the front. The stationary portion of the front is forecast to
continue to weaken through the weekend. The frontal remnants
will drift southward towards the NE Caribbean Sea islands.
Precipitable water GFS model guidance indicates that moisture
and precipitation will increase for the NE Caribbean islands
through the weekend. before diminishing late Sun.

Farther east, another strong 1042 mb surface high centered near
40N21W dominates the area E of the cold front maintaining rather
stable weather over much of the central and eastern sections of
the area, except for the far eastern portion S of 24N and E of 40W
where abundant mid and upper level clouds are streaming eastward
towards Africa ahead of a mid to upper level trough located N of
15N between 30W and 40W.

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

$$
Aguirre
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