Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 201717

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1217 PM EST Tue Feb 20 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 
1715 UTC. 


Caribbean Sea Gale Warning: A tight surface pressure gradient 
continues between high pressure in the western Atlantic and 
lower pressure in northern sections of South America. This 
pattern is supporting winds reaching gale-force strength within 90
nm of the coast of Colombia this week. Wave heights within the 
area of gale force winds will range between 12-16 ft. Please read 
the latest NHC High Seas Forecast under AWIPS/WMO headers 
MIAHSFAT2/FZNT02 KNHC for more details.


The monsoon trough axis extends from the coast of Africa near 
07N11W southwestward to 00N24W. The ITCZ crosses the equator near
24W and remains south of the discussion area to the coast of 
Brazil. Scattered moderate convection is south of 02N between 
15W-20W and west of 30W.



A surface ridge extends westward across the entire basin from 
the Atlantic. Scatterometer data depicts moderate southeasterly 
winds across most of the area. Satellite imagery shows scattered 
shallow convection over the east Gulf mainly east of 87W while
fair weather prevails elsewhere. Expect increasing winds and 
building seas through mid-week as high pressure strengthens in 
the western Atlantic. A thermal trough will develop over the 
western Yucatan Peninsula each evening, drifting westward across 
the Bay of Campeche during overnight hours, then dissipate in the 
SW Gulf by late morning.


Please refer to the SPECIAL FEATURES section for details about 
the Gale Warning currently in effect near the coast of Colombia.

A tight pressure gradient across the basin created by the 
combination of strong high pressure over the Atlantic and lower 
pressure over northwest Colombia is producing strong east winds 
between 70W-80W, while moderate to fresh winds prevail elsewhere. 
Trade wind showers are evident from satellite imagery across the
basin. The high pressure will strengthen through Wednesday, 
increasing the winds and building seas east of 80W in the 
Caribbean and the Tropical Atlantic waters.


A cold front extends over the central Atlantic from 31N35W to 
23N52W then becomes diffuse west of 53W. Scattered moderate 
showers are observed along northern portion of the front mainly
north of 28N, and low clouds with scattered rain prevails along 
the remainder of the frontal boundary. Broad high pressure 
centered north of 30N prevails across the rest of the basin. The 
front will become stationary during the next 06-12 hours and 
should dissipate later today. The existing area of high pressure 
will be fortified by a stronger subtropical high through mid-week.

For additional information please visit 



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Page last modified: Tuesday, 20-Feb-2018 17:17:20 UTC