AXNT20 KNHC 201147

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
647 AM 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 0600 UTC surface analysis and satellite imagery through 1145 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 will support winds pulsing to minimal gale-force near the coast of Colombia each night 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 07N12W southwestward to 01N20W. The ITCZ crosses the equator near 21W and remains south of the discussion area to the coast of South America. Scattered moderate convection is from 00N-05N between 11W-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 isolated shallow convection in the SE Gulf and fair weather elsewhere. Expect increasing winds and building seas through Wed as high pressure strengthens in the western Atlantic. A thermal trough will develop over the western Yucatan Peninsula each evening through mid week, drift 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 a Gale Warning 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 NW Colombia is producing strong east winds between 70W-80W, while moderate to fresh winds prevail elsewhere. Trade wind showers are evident from satellite imagery primarily east of 70W. The high pressure will strengthen through Wednesday, increasing the winds and building seas east of 80W in the Caribbean and the Tropical N Atlantic waters through mid-week.


A cold front extending from 32N40W to 28N48W to 27N56W becomes diffuse west of 60W. Scattered moderate showers are observed along a pre-frontal trough, and low clouds with scattered light rain are evident along 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 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