000 AXNT20 KNHC 031757 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 157 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...MONSOON TROUGH/ITCZ... Scatterometer wind data indicate that the monsoon trough extends from the 07N11W to 03N16W to 02N30W. The intertropical convergence zone continues from 02N30W to 00N51W. Scattered moderate to strong convection was occurring within 120 nm N and 240 nm S of the monsoon trough east of 21W. West of 21W, scattered moderate convection was located within 120 nm either side of the monsoon trough and ITCZ to the coast of NE Brazil. ...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 SE winds are expected to increase to fresh to strong later today between the ridge to the east and a trough over the southern Plains. Seas are generally 5 to 7 ft west of 90W and 4 to 5 ft E of 90W. Winds and seas will diminish later today. Across the Straits of Florida, E winds of 20 to 25 kt continue. Seas could reach 7 ft this afternoon due to the persistent long- fetch easterly winds flowing across the Florida Current. Widely scattered showers continue between the Florida Keys and Cuba. The persistent ridge will allow the fresh to strong winds to continue into tonight with seas reaching 9 ft, before diminishing through early next week as the ridge weakens. A weakening surface trough over the SW Gulf and Bay of Campeche is moving westward. Winds are 10 to 15 kt, but they will increase to 15 to 20 kt by this evening. CARIBBEAN SEA... Persistent high pressure north of the area is supporting fresh to strong trade winds across the south-central Caribbean with seas of 8 ft. 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. Moisture will remain high across east and central Cuba through Saturday while gradually spreading eastward across Hispaniola, keeping the likelihood of scattered to numerous showers and tstms due to a developing mid-/upper-level low near the Bahamas drifting southward across eastern and central Cuba to the north central Caribbean. This unstable weather pattern could persist through the remainder of the week over the eastern half of Cuba and parts of Hispaniola as the broad upper- low meanders over the same area. ATLANTIC OCEAN... A stationary front extends from 31N52W to 26N70W in the central Bahamas. The front becomes diffuse over central Cuba. A surface extends from 26N70W southward into the Windward Passage. Water vapor satellite imagery indicates a mid-level low has developed just north of the Turks and Caicos beneath region of upper- level divergence associated with a strong westerly subtropical jetstream. A large area of multi-layer clouds with embedded showers and tstms was located NE through Se of the mid-level low, with a general increase in the amount and intensity of the convection noted during the past 6 hours. Ship and buoy reports, along with recent scatterometer data indicate winds of 20-25 kt continue south of the front and east of the trough from near Hispaniola eastward to 63W. Wind gusts of 35 to 40 kt will be possible in some of the stronger thunderstorms. A sharp upper-level trough extends from the north central Atlantic southward across Bermuda, to the developing mid-level low. Gradual develop of the low into the upper- and lower-levels is expected through Saturday as the system drifts southward to eastern/central Cuba by late Friday. 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 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 $$ Stewart