[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
704 PM 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A very tight pressure gradient exists
between a cold front extending from 32N44W to 24N51W to 22N60W,
where it becomes a dissipating stationary front to the NW coast of
Haiti, and strong high pressure of 1038 mb centered N of the area
near 37N66W. This continues to produce a large area of near gale
to minimal gale force NE to E winds over the waters N of the front
to 24N and between 60W and 75W. Given the long duration of these
winds, the resultant seas have build to the range of 12 to 18 ft
within the area of these winds. These conditions are forecast to
continue through early Sun, at which time the gradient should
slacken enough tot allow for the winds to diminish to strong
category, however seas are forecast to remain quite high in the
13 to 15 ft range. The previous gale warning for the waters W of
the Bahamas including the Straits of Florida and far eastern Gulf
of Mexico near 83W was allowed to expire this afternoon. E winds
over those waters have diminished to the strong to near gale
force range. Fresh to strong NE to E winds are elsewhere W of the
front, including through the Atlantic passages in the Bahamas.
Latest model guidance indicates these winds will diminish to just
below gale force on Sun morning near sunrise. 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 and into the early morning hours through Tue, and possibly
well into next week. 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: Strong high pressure system, this
one of 1040 mb is centered NE of the Azores near 41N20W. The
tight pressure gradient to its SE and S is forecast to maintain NE
gale force winds to reach minimal to strong gale force over Meteo
France marine zone of Canarias through Sun night before
diminishing to strong winds on Sun. Under same tight gradient,
minimal gale force NE winds are expected to continue over marine
Madeira through Mon night. Please refer to Meteo France Weather
Bulletins for more information.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough axis extends from the coast of Africa near
06N10W to 04N14W where the ITCZ begins and then continues along
01N20W to 0N30W to 0N40W to 01S50W. Scattered moderate convection
is within 210 nm either side of the axes.

...DISCUSSION...

GULF OF MEXICO...

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

Strong surface high pressure centered over the NW Atlc is
supporting a large area of fresh to strong E winds E of 90W. The
exception is in the far SE Gulf and Straits of Florida where the
recent gale force E winds have diminished to the strong to
near gale force category as of the afternoon hours. These winds
will diminish further on Sun as strong ridging over the eastern
Gulf begins to weaken. An upper level short-wave supports a 1019
mb low off the Texas coast near 28N95W from where a stationary
front extends northeastward to SE Louisiana near 30N89W. Another
stationary front extends from the low to inland the S Texas coast
near Brownsville. Latest radar displays reveal scattered showers
and thunderstorms with frequent lightning along and within 90 nm
of the Texas coast, and N of 26N between 87W and 90W. Scattered
showers and isolated thunderstorms are over in the SE Gulf from
23N to 28N between 84W and 89W being supported by upper level
diffluent flow. A rather progressive upper level pattern will
bring surface low pressure southeastward towards the area of
southeastern Louisiana or southwestern Mississippi early tonight,
with a trailing cold front across the NW Gulf waters. The low is
forecast to rapidly move across the NE Gulf on Sun while pushing
the 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 regarding
the gale conditions near the coast of Colombia.

Fresh to strong NE winds prevail at the lee of Cuba. Fresh to
strong trades are occurring elsewhere across the basin, except for
the gale force winds near the coast of Colombia as described
above under SPECIAL FEATURES. A surface trough along the eastern
Yucatan Peninsula and Belize continue to support scattered
showers and isolated thunderstorm over the Gulf of Honduras.
Isolated showers and thunderstorms are noted over Hispaniola
being supported by upper level diffluent flow. Strong to near
gale force NE winds are likely to occur through the Windward
Passage next week. 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...
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 32N44W to 24N51W to
22N60W, where it becomes a dissipating stationary front to the NW
coast of Haiti. Meanwhile, strong high pressure of 1038 mb is
located well N of the area at 37N66W. The resultant tight
gradient support near gale to minimal gale force winds along with
large seas in the SW N Atlc from the front N to 24N and between
60W and 75W. These conditions are expected to continue into Sun
morning before diminishing to strong winds. Areas of rain and
scattered showers are within 120 nm E of the front N of 28N, and
within 90 nm E of the front from 26N to 28N. The stationary
portion of the front is forecast to dissipate through Sun.
The frontal remnants will drift southward towards the NE
Caribbean Sea islands, most likely as a shearline. 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 E, a 1040 mb high pressure system centered near 41N20W
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 16N and E of 31W where
abundant mid and upper level clouds are streaming eastward towards
Africa ahead of a mid to upper level trough located N of 10N
between 30W and 40W.

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

$$
Ramos/Aguirre
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