Tropical Weather Discussion
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000
AXNT20 KNHC 140005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
705 PM EST Sat Jan 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
2315 UTC.

...SPECIAL FEATURES...

...Gale Warning within 60 nm of the coast of Nicaragua...

A cold front extends from central Cuba to NW coastal Honduras. The
front will move slowly southeastward and become stationary from
eastern Cuba to Costa Rica tonight. Fresh to locally strong N
winds are expected behind the front through tonight. Wind speeds
are forecast to increase even more behind the front on Sunday
morning as strong high pressure builds across the NW Caribbean
Sea and in northern Central America. The increase in wind speeds
will allow strong to minimal gale-force northerly winds to blow
behind the front, and within 60 nm of the coast of Nicaragua, with
building seas of 8-11 feet. Please read the latest NHC High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...THE MONSOON TROUGH/THE ITCZ...

The monsoon trough extends from the coast of Africa near 06N10W to
04N15W to 02N22W. The ITCZ continues from 02N22W to 02N40W, to the
Equator at along 45W, and along the Equator at 50W at the coast of
Brazil. Precipitation: Isolated moderate to locally strong
rainshowers are within 360 nm to the N of the ITCZ between 30W
and 52W.

...DISCUSSION...

...THE GULF OF MEXICO...

A surface ridge passes through central Texas, to a 1034 mb high
pressure center that is near 22N98W in the coastal plains of
Mexico, to the Isthmus of Tehuantepec of southern Mexico, to
central Guatemala. High pressure centers of 1042 mb and 1043 mb
are in the northern Plains of the U.S.A. Cold air stratocumulus
clouds cover much of the Gulf of Mexico, with the advection of
cold air over relatively warm waters. Reinforcing cold air will
move through the eastern Gulf for the rest of today, behind a
secondary cold front that currently is moving through north-
central Florida. The second front is forecast to reach south
Florida tonight, bringing another round of cold temperatures.
High pressure will continue to prevail across the area through
early on Monday. The high pressure will slide eastward on Tuesday
night as the next cold front moves over the NW gulf waters. Fresh
northerly winds will persist across the eastern Gulf tonight and
Sunday, with gentle to moderate NE-E winds elsewhere.

...THE CARIBBEAN SEA...

A cold front extends from central Cuba to NW coastal Honduras.
Please read the SPECIAL FEATURES section for more details about
the winds and the sea heights that are and will be associated with
the cold front. A surface trough is along 77W/78W from 13N,
crossing the western part of Jamaica, to southern sections of SE
Cuba. Precipitation: isolated moderate rainshowers are within 520
nm to the E and SE of the front, including in parts of Hispaniola,
and elsewhere in the Caribbean Sea.

Rainshowers are possible elsewhere in the Caribbean Sea, from 72W
eastward, in areas of broken low level clouds in surface tradewind
flow.

...HISPANIOLA...

Isolated to scattered passing showers are expected across the
island today under the influence of a ridge. Moisture will
continue to be limited on Sunday.

...THE ATLANTIC OCEAN...

A cold front passes through 32N72W, across the northern half of
the Bahamas, beyond central Cuba, and into the Caribbean Sea.
Precipitation: widely scattered moderate to isolated strong
rainshowers are within 180 nm to the E and SE of the colf front.
A second cold front passes through 32N75W beyond central Florida.

A surface trough is along 23N50W to 18N52W. Precipitation: widely
scattered moderate to isolated strong rainshowers are from 18N to
26N between 49W and 58W.

A second surface trough is along 15N53W to 10N55W. Precipitation:
isolated moderate to locally strong rainshowers are from 10N to
14N between 53W and 60W.

Fresh to strong SW-W winds are blowing between fronts. The main
front will become stationary from 31N73W to the central Bahamas
and to eastern Cuba on Sunday, while the secondary front will
merge with the main front tonight.

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

$$
mt



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