000 AXNT20 KNHC 270521 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1221 AM EST Tue Feb 27 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... A strong 966 mb low pressure system with hurricane force winds centered over the north-central Atlantic near 39.5N33W supports a cold front from 37N24W to 24N40W to 27N55W. A strong pressure gradient associated with the deep low pressure and cold air advection associated with cold front are supporting gale force winds north of the front and east to 35W. Gale conditions are forecast to prevail through tonight then will gradually diminish as the low pressure moves farther away from the area and the front dissipates. Gale force winds are also occurring ahead of the front as noted in a recent scatterometer pass, impacting the area east of 35W to the Canary Islands. Altimeter satellite passes are showing seas of 15 to 25 ft in northerly swell north of 20N and east of 50W. For more details, refer to the NHC High Seas Forecast under AWIPS/WMO Headers MIAHSFAT2/FZNT02 KNHC. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic through the coast of Liberia near 06.5N10.5W to 01N16W, where it transitions to the intertropical convergence zone and continues to the coast of Brazil near 03N44W. Scattered moderate convection is from 02N to 04N between 20W and 25W, and from 02S to 00N between 25W and 28W. ...DISCUSSION... GULF OF MEXICO... A weakening stationary front reaches from near Panama City Florida to Brownsville Texas. Radar from the across the northern Gulf shows a few showers along and north of the frontal boundary, mainly over the northeast Gulf, and what may be light rain or drizzle in patches over the north central and northwest Gulf. Dewpoints are in the upper 60s to lower 70s over the northwest Gulf, where platforms are showing areas of fog. Light southeast winds are noted south of the front with 2 to 4 ft seas. For the forecast, the front will weaken through tonight. High pressure will build across the region Tue. Another, stronger cold front will move into the NW Gulf Wed night. Gale conditions are possible over the SW Gulf Thu night behind this front. CARIBBEAN SEA... High pressure north of the area centered between Bermuda and the northern Bahamas is supporting fresh to strong trade winds across the south central Caribbean and in the lee of Cuba. Moderate to fresh trade winds persist elsewhere. An upper low is centered north of the Mona Passage near 21.5N 68.5W with a sharp upper trough reaching to Nicaragua. This is supporting a few showers over Hispaniola and over portions of the northeast Caribbean. land based observations near Santa Marta Colombia show strong trade winds currently, and this is indicative of the strong flow off Colombia expected to reach near gale force overnight due to added drainage effects. Little change is expected over the next several days with strong winds pulsing off Colombia, and possibly the Windward Passage through mid week. Large long period swells will reach the Atlantic passages in the Leeward and Windward Islands late in the week. ATLANTIC OCEAN... A weak pressure pattern dominates the Atlantic waters west of 50W, focuses on 1023 mb high pressure centered 28N68W, supporting gentle to light winds north of 22N and moderate trade winds south of 22N. Scattered showers and thunderstorms are active from 22N to 24N between 65W and 70W associated with an upper low near 22N66W. Looking ahead, a cold front will move off the southeast coast of the U.S. Tue, and reach the central Bahamas Wed evening, as high pressure builds north of the front. Strong low pres north of the area will bring a cold front to area Thu night, with deteriorating conditions over the waters north of 27N. The system will support gales Fri night through Sat night over the northeast waters. A significant swell event will accompany this system, affecting all waters east of north Florida and Bahamas at the end of the week. East of 50W, fresh to strong northwest 25N to 30N outside the areas of strong to gale force winds noted in the Special Features sections. Because the subtropical ridge is disrupted by the deep low pressure over the north central Atlantic, only gentle to moderate trade winds deeper into the tropics. Northerly swell of 8 to 8 to 12 ft is reaching as far south as 15N. Looking ahead for the waters east of 50W, winds and seas will gradually subside north of 25N through mid week, just ahead of another powerful low pressure system approaching from the western Atlantic, brining strong to near gale force winds and large seas to the area north of 20N between 40W and 50W by late week. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen