[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171729
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1229 PM 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 1200 UTC surface analysis and satellite imagery through
1700 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 feet to 15 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 the southern coastal sections
of Liberia near 05N08W, to the Equator along 18W. The ITCZ
continues from the Equator along 18W, to 02S28W, to 04S33W, and
to the coast of Brazil near 04S38W. Precipitation: scattered to
numerous strong rainshowers are from 04N southward between the
Prime Meridian and 01W. widely scattered moderate to isolated
strong from 01N to 03N between 08W and 11W. isolated moderate to
locally strong rainshowers are elsewhere from 10N southward.
Upper level SW wind flow is to the SE of the line that passes
through 24N16W 21N40W, to 16N50W and to 14N63W in the Caribbean
Sea.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge extends from an Atlantic Ocean 1026 mb high
pressure center that is near 27N66W, to central Florida, to 26N90W
in the Gulf of Mexico, to 21N98W in interior sections of Mexico.

A ridge will dominate the Gulf region this weekend producing
mainly gentle-to-moderate winds in the western Gulf, and light-
to-gentle winds in the eastern Gulf, with the exception of
moderate winds in the SE waters and the Straits of Florida.
Expect increasing winds and building seas by early next week as
high pressure strengthens in the western Atlantic Ocean. A
thermal trough will develop in the western Yucatan Peninsula
during each afternoon. The trough will drift westward across the
eastern Bay of Campeche during the overnight hours, and then
dissipate in the southwest Gulf waters 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 17/1200 UTC...according
to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...
MIATPTPAN/SXCA01 KNHC...are: 0.39 in St. Thomas in the U.S. Virgin
Islands, 0.18 in San Juan in Puerto Rico, 0.07 in Montego Bay in
Jamaica, and 0.03 in Guadeloupe.

A tight pressure gradient between a high pressure system that is
in the western Atlantic Ocean, and lower pressure in northern
sections of South America, will continue to support pulsing winds
of minimal gale-force near the coast of Colombia through the
forecast period. Fresh to locally strong trade winds are expected
elsewhere across the Caribbean Sea. The high pressure will be
reinforced by a stronger system on Monday. The stronger system
will bring increasing winds and building seas across the eastern
and central Caribbean Sea, and the Tropical N Atlantic waters from
Monday through Wednesday.

ATLANTIC OCEAN...

An upper level trough extends from a 25N45W cyclonic circulation
center, to 17N50W, to 13N61W in the SE Caribbean Sea. One surface
trough is along 31N31W 29N38W 28N45W 26N47W. A second surface
trough is along 26N45W 23N44W 20N44W. isolated moderate to locally
strong rainshowers are from 22N to 30N between 38W and 46W.

Broad surface anticyclonic wind flow covers the Atlantic Ocean
from 17N northward from 50W westward. A 1026 mb high pressure
center is near 27N66W.

An Atlantic Ocean ridge, E-to-W along 27N, will shift gradually N
to be along 28N tonight, 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. The ridge will be reinforced by a stronger
high pressure system on Monday.

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

$$
MT
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