000 AXNT20 KNHC 032353 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 752 PM EDT Thu May 3 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 2315 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through the coastal sections of Liberia, then continues SW to near 02N20W. The ITCZ stretches from 02N20W to the Equator at 50W. Scattered moderate to isolated strong convection is from the Equator to 03N between the Prime Meridiam and 07W. Similar convection is also noted over parts of Liberia, and from the Equator to 05N between 18W-24W. ...DISCUSSION... GULF OF MEXICO... A ridge extends westward along the Gulf coast to SE Louisiana, and then continues southwestward to NE Mexico. Moderate to fresh anticyclonic flow is noted across the Gulf waters. Scatterometer data indicate fresh to locally strong easterly winds across the Straits of Florida. These winds are the result of the pressure gradient between the aforementioned ridge and a surface trough moving slowly across the Bahamas. These winds will persist tonight across the Straits of Florida and the SE Gulf, with seas building up to 8-10 ft across the Straits of Florida. Doppler Radar shows a few showers across the Florida Keys and the Straits of Florida. A thermal trough will develop over the northwest coast of Yucatan during the evening, and drift westward across the SW Gulf before dissipating later in the morning. A surge of fresh to occasionally strong NE to E winds will accompany this trough. This pattern will repeat each evening through the period. CARIBBEAN SEA... Persistent high pressure north of the area is supporting fresh to strong trade winds across the south-central Caribbean, including the Gulf of Venezuela, with seas to near 8 ft within 90 nm of coast of Colombia. Moderate to locally fresh trades are noted elsewhere. Increasing winds and building seas can be expected across the waters E of the Lesser Antilles first, then across the eastern Caribbean tonight into Fri due to the pressure gradient between the ridge to the north and a surface trough moving across the Bahamas. This weather pattern will keep relatively low winds of 15 to 20 kt off the coast of Colombia, and 10 to 15 kt elsewhere over the western Caribbean. As of 1800 UTC, a surface trough extends over eastern Cuba and Jamaica. This trough is helping to induce scattered showers and tstms over parts of eastern Cuba, Jamaica, and near the southern peninsula of Haiti. Moisture will remain high across easteran Cuba, Jamaica and Hispaniola through Fri night, and begin to increase over west-central Cuba, south Florida and the Florida Keys Fri night into Sat, keeping the likelihood of scattered to numerous showers and tstms. This unstable weather conditions will be associated with a surface trough moving westward across the Bahamas, reflection of a mid/upper-level low located near the central Bahamas. This mid/upper level low is forecast to drift southward across eastern Cuba on Fri, where it will remain on Sat, then reach Jamaica on Sun. A fresh to strong SE wind flow will follow the trough, transporting abundant tropical moisture. ATLANTIC OCEAN... A weakening stationary front extends from 31N52W to 26N70W. A surface trough extends from this point across the SE Bahamas and eastern Cuba. Water vapor satellite imagery indicates the presence of a mid/upper level low over the central Bahamas. A diffluent pattern aloft on the east side of the low is helping to support a large area of multi-layer clouds with embedded showers and tstms. This convective activity is affecting the SE Bahamas, the Turks and Caicos Islands, and parts of eastern Cuba and Hispaniola. Ship and buoy reports, along with recent scatterometer data indicate fresh to strong winds on either side of the frontal boundary, mainly from 22N-28N between 65W-71W. Gusty winds of 35 to 40 kt will be possible in some of the stronger thunderstorms. The surface trough is expected to gradually develop into a broad low pressure system and move WNW between the Bahamas and Cuba during the next 48 hours, and be near southern Florida by early Saturday. Active weather spawned by the instability of this large and complex deep-layer low, along with abundant moisture drawn northward in a fresh to strong SE wind flow, will result in numerous showers and thunderstorms steadily developing and overspreading across most of the Greater Antilles, Bahamas, Turks and Caicos, and adjacent waters by Fri, and gradually spread westward across the Straits of Florida and into the Florida peninsula over the weekend. Fresh to strong NE winds are expected ahead of the trough, and fresh to strong SE winds will follow the trough, impacting mainly the waters S of 27N-28N and W of 65W. The remainder of the Atlantic is under the influence of a 1030 mb high pressure located near the Azores. This system is producing moderate to fresh trade winds across the deep tropics, where seas are reaching 6 to 8 ft in NE to E swell. For additional information please visit http://www.hurricanes.gov/marine $$ GR