[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132350
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
649 PM EST Tue Feb 13 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...

Caribbean Gale Warning: A tight gradient between a strong surface
ridge over the N Atlantic Ocean and lower pressures in northern
South America will continue to support gale-force winds near the
coast of Colombia during the night time hours through the week.
Seas associated with these gale conditions are forecast to be 14
to 18 ft, subsiding some later in the week. Please read the latest
NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough axis extends southwestward from the coast of
Africa near 05N10W and crosses the equator near 19W. The ITCZ is
located to the S of the equator. Scattered moderate isolated
strong convection is within 120 nm S and 30 nm N of the axis
between 10W-12W. Similar is well S of the axis within 30 nm
of a line from 01N02W to 01N05W to 01N10W.

...DISCUSSION...

GULF OF MEXICO...

A cold front extends from the western Atlantic to inland NE
Florida where it becomes stationary southwestward to 29N88W
and a warm front from there to 27N94W to 26N96W S to 23N96W. It
transitions back to a stationary front again to inland the coast
of Mexico near Coatzacoalcos. A trough is ahead of the frontal
boundary from 23N93W to inland Mexico just W of Nuevo Progreso,
while another trough extends from just W of the front near 25N95W
northwestward to just S of Corpus Christi, Texas. Isolated showers
and thunderstorms moving northward are NW of the warm front
between 90W-95W. Patches of rain and isolated thunderstorms are
W of the stationary portion in the SW and far W central portions
of the gulf. Isolated showers in very moist moderate to fresh E
flow are over portions of the eastern gulf and Straits of Florida.
High pressure W of the front is surging southward over the NW
Gulf and across eastern Mexico. Strong northerly winds are S of
21N near the coast of Mexico. Moist southerly flow moving over the
NE Gulf ahead of the front in response to a mid to upper level
trough sliding eastward across the NE Gulf is producing widespread
showers north of 25N east of the trough. The warm front will
weaken as it slowly lifts northward as a warm front through
early on Wed.

CARIBBEAN SEA...

Please refer to the SPECIAL FEATURES section above for details
about the gale-force winds expected near the coast of Colombia.

Satellite water vapor imagery shows dry and stable atmospheric
conditions across the basin. Fast westward moving shallow trade
wind showers, with gusty winds, are observed over much of the
basin, except in the lee of Cuba and waters between Haiti and 76W
and to the S of 13N between Colombia and 77W. The shower activity
is more prevalent N of 12N and E of 71W to across the Lesser
Antilles. Surface observations during the morning and early
afternoon hours indicated strong wind gusts with these showers as
they passed across the Leeward Islands and northern portion of
the Windward Islands. The island of Dominica reported a wind gust
to 34 kt at 16Z as a light shower went by. A strong ridge N of the
area anchored by a 1033 mb high over the central Atlc near 32N53W
extends across the northern half of the Caribbean, with the
associated pressure gradient supporting fresh to strong trade
winds east of 80W. Seas are 14 to 18 ft near Colombia and 8 to 12
ft elsewhere. Strong winds are also occurring through the Atlc
passages, and are expected to continue through at least Wed.

ATLANTIC OCEAN...

Broad surface high pressure over the area is associated with a
1033 mb centered over the N central Atlantic near 32N53W and
moving southwestward is supporting fresh to strong E-NE winds
over most of the region, except close to the ridge axis N of 25N.
Isolated showers, moving quickly westward, are noted from 13N to
18N and to the W of 52W, including over much of the Leeward
Islands. This shower activity will move across the Leeward Islands
through early this evening, and will be attended by strong gusty
winds. Other isolated shower activity moving rapidly westward in
moderate to fresh moist easterly flow are seen S of 26N and W of
57W. This activity is moving over the waters between the Bahamas
and Cuba as well as across the Straits of Florida.

A weak cold front along a position from 31N76W to inland NE
Florida just S of Jacksonville, Florida as of 15Z will slowly sink
southward to near 29N and westward to the vicinity of Daytona
Beach by early this evening. The front is expected to become
stationary across the central Atlantic Wed through Thu. Scattered
showers and isolated thunderstorms along and within about 60 nm S
of this frontal W of 77W will continue rather active through
tonight as an upper level trough shifts eastward from the NE Gulf.
The next cold front is forecast to move over the NW forecast
waters by early on Sat morning.

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

$$
JA/ERA
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