Tropical Weather Discussion
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845
AXNT20 KNHC 171206
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
706 AM EST Sat Feb 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 0600 UTC surface analysis and satellite imagery through
1130 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: A tight surface pressure gradient,
that exists between surface high pressure in the western Atlantic
Ocean, and lower surface pressure in northern sections of South
America, should continue to support winds pulsing to minimal
gale-force near the coast of Colombia through Sunday. The
resultant wave heights with the gale-force winds are forecast to
range from 10 to 14 feet. Please read the latest NHC High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal border sections of
Sierra Leone and near Liberia near 07N11W, to the Equator along
21W. The ITCZ continues from the Equator along 21W, to 01S30W, to
02S38W, and to the coast of Brazil near 03S31W. Precipitation:
isolated moderate to locally strong rainshowers from 10N
southward. Upper level SW wind flow is to the SE of the line that
passes through 22N17W 20N40W, to 15N65W in the Caribbean Sea.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge extends from the Atlantic Ocean near 27N75W,
to a 1022 mb high pressure center that is near 27N83W along the
Florida west coast, southwestward to Mexico near 20N97W.

Weak high pressure will persist across the E Gulf through Saturday,
when a weak cold front will stall E to W across the northern and
northwest waters. The cold front will retreat northwestward on
Sunday night into Monday. Locally dense fog will linger north of
27N west of 91W through the morning hours. A thermal trough will
develop in the western Yucatan Peninsula during each afternoon,
drift westward across the eastern Bay of Campeche during the
overnight hours, and then dissipate in the southwestern corner of
the Gulf of Mexico by late each morning.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for details regarding
the Gale Warning near the coast of Colombia.

Rainshowers are possible, in areas of broken-to-overcast low
level clouds, across the entire area. 24-hour rainfall totals that
are listed for the period that ended at 15/1200 UTC...according
to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...
MIATPTPAN/SXCA01 KNHC...are: 0.09 in Guadeloupe.

An Atlantic Ocean ridge, extending E-to-W along 27N-28N, will
maintain strong-to near gale-force trade winds across the central
and southwestern Caribbean Sea through the weekend, with nocturnal
gale-force wind conditions along the northwestern coast of
Colombia. Fresh-to-locally strong trade winds are expected
elsewhere across the Caribbean Sea. Strong high pressure across
the NW Atlantic Ocean will build S across the region from Sunday
night through Wednesday, to produce strong trade winds across the
eastern Caribbean Sea and the tropical Atlantic Ocean.

ATLANTIC OCEAN...

An upper level trough extends from a 25N45W cyclonic circulation
center, to 17N50W, to 13N61W in the SE Caribbean Sea. Widely
scattered to scattered moderate and isolated strong rainshowers
are from 24N to 30N between 40W and 45W.

An Atlantic Ocean ridge, E-to-W along 27N, will shift gradually N
to along 28N on Saturday night, and then retract eastward,
allowing a weak cold front to move off the southeast United States
on Sunday. The front will stall quickly and dissipate across the
northwestern waters on Monday. Gentle-to- moderate winds will
prevail north of the ridge, with moderate-to- fresh winds expected
generally south of 25N, except becoming strong along the north
coast of Hispaniola and the northern approach to the Windward
Passage each evening.

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

$$
MT



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