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 http://www.hurricanes.gov/marine