000 AXNT20 KNHC 181737 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1237 PM EST Sun Feb 18 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. ...SPECIAL FEATURES... Caribbean Sea Gale Warning: A tight surface pressure gradient continues between a surface high pressure in the western Atlantic and lower surface pressures in northern sections of South America. This pattern supports winds pulsing to minimal gale force near the coast of Colombia through early next 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. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the eastern Atlantic near 07N12W to 00N22W. The ITCZ continues from that point to 03N39W. Scattered moderate convection is within 60 nm on either side of the ITCZ between 23W and 40W. ...DISCUSSION... GULF OF MEXICO... A surface ridge extends across the basin anchored by a 1023 mb high centered over central Florida. A frontal boundary extends across the coastal Gulf states with little to no convection at this time. A subtle pre-frontal trough is over the northeast waters from 30N86W to 28N88W. Scattered showers are noted with this trough. To the southwest, a surface trough continues moving westward across the Bay of Campeche with no convection. Scatterometer data depicts light to gentle southeasterly winds over the northern half of the basin while gentle to moderate southeast winds prevail south of 25N. Expect increasing winds and building seas by early next week as high pressure strengthens in the western Atlantic Ocean. The thermal trough will develop again over the western Yucatan Peninsula each afternoon, drifting westward across the eastern Bay of Campeche during the overnight hours, and then dissipate in the SW Gulf waters by the late morning hours. CARIBBEAN SEA... Please refer to the SPECIAL FEATURES section for details regarding the Gale Warning near the coast of Colombia. Scattered low-topped showers will continue moving across the basin transported by moderate to fresh trades. The 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 early next week. Fresh to locally strong trade winds are expected elsewhere across the Caribbean Sea. The high pressure will be reinforced by a stronger one system on Monday. This stronger system will bring increasing winds and building seas across the eastern and central Caribbean, and the Tropical N Atlantic waters possibly into the middle of next week. ATLANTIC OCEAN... Broad area of high pressure prevails across the basin, centered by a 1026 mb high near 28N67W and a 1025 mb high near 29N39W. A weakness in the ridge was analyzed as a surface trough, extending from 28N43W to 20N44W. A frontal system extends north of the area across the central Atlantic between 40W-60W. The eastmost portion of the front will approach 30N during the next 24 hours with some convection. Another weak frontal boundary will approach the west Atlantic from the north by the same time with showers. The ridge will be reinforced by a stronger high pressure system through Tuesday. For additional information please visit http://www.hurricanes.gov/marine $$ ERA