000 AXNT20 KNHC 170004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 704 PM EST Fri Feb 16 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... Caribbean Sea Gale Warning: A tight surface pressure gradient between a high pressure system over the western Atlantic and lower pressure over northern South America should continue to support winds pulsing to minimal gale-force near the coast of Colombia through Sun. The resultant with the gale force winds are forecast to range from 10 to 14 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 axis enters the eastern Atlantic near 07N12W and continues to 01N19W, where latest scatterometer data indicates the ITCZ begins and dips to S of the Equator at 23W. Scattered moderate isolated strong convection is within 180 nm S of the axis between 12W-15W. Scattered moderate convection is within 60 nm S of the axis between 20W-23W, and also N of the axis within 30 nm of line from 02N24W to 03N28W. ...DISCUSSION... GULF OF MEXICO... The western extension of Atlantic across the area is maintaining pretty tranquil weather conditions throughout the basin. In addition, satellite water vapor imagery depicts abundant dry air in the mid and upper-levels of the atmosphere. Surface observations and scatterometer data indicate that the winds are light and generally southeast or southerly across much of the area. Observed waveheights are in the 3 to 5 ft range throughout, and little change is expected through Sun. A weak surface trough extends into the NE Gulf from the Florida panhandle along a position from near 30N85W southwestward to near 27N87W. Only isolated showers are near this trough. Areas of dense fog are expected over portions of gulf mainly N of about 27N tonight into Sat producing sharply reduced visibilities. Little change in the present synoptic pattern is expected through Sun, however, winds and seas are forecast to increase by early next week when high pressure strengthens over the western Atlantic. CARIBBEAN SEA... Please read the SPECIAL FEATURES section for details about the Gale Warning near the coast of Colombia. Only patches of clouds and embedded quick-moving isolated showers are seen across the Caribbean Sea today. The trade winds in the area are fresh to strong, and they are even stronger near the coast of Colombia as discussed above. These winds are occurring due to the tight pressure gradient between a 1024 mb high over the western Atlantic and the typical lower pressures found over northern South America. No significant changes are expected to occur on Saturday, but winds and seas will likely increase over the eastern and central Caribbean on Sun and early next week when the gradient tightens from stronger high pressure that builds to the N of the area. ATLANTIC OCEAN... Tranquil conditions and fairly light winds are occurring across the western Atlantic supported by a surface ridge and dry and stable air aloft. Over the central Atlantic, an upper-level low and accompanying surface trough is producing scattered moderate convection from 28N-32N between 41W- 45W. Scattered moderate isolated strong is noted over the deep tropics from 2N-6N between 43W-50W in association with a surface trough and diffluent flow aloft. No significant weather is occurring over the eastern Atlantic, but earlier scatterometer data indicated that the trade wind flow is fresh to strong south of about 20N. For additional information please visit http://www.hurricanes.gov/marine $$ MT/Aguirre