000 AXNT20 KNHC 091043 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 643 AM EDT Wed May 9 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 0600 UTC surface analysis and satellite imagery through 1030 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough meanders westward across tropical western Africa and terminates along the coast of Guinea-Bissau near 12N16W. The ITCZ begins near 06N15W and continues to 01N30W to 00N45W to the coast of northern Brazil near 01S47W. Scattered moderate and isolated strong convection are within 180 nm of either side of the ITCZ axis. ...DISCUSSION GULF OF MEXICO... 1019 mb high pressure south of Mobile Bay near 28N88W is embedded along a ridge reaching from the western Atlantic to the Texas coast. Gentle to light winds are noted over the northern Gulf, and moderate easterly winds are observed over the southern Gulf, south of the ridge axis. A few showers are likely ongoing over the south central Gulf, influenced by the southern stream jet ahead of an upper trough moving eastward across the Southern Plains and northern Mexico. The ridging will persist from the western Atlantic across the northern Gulf through Sun night. Moderate E to SE flow will set up over most areas, with 2 to 4 ft seas. The upper trough will stall across the far northwest Gulf and amplify, allowing increased deep layer moisture and possible a few showers over the eastern Gulf through late week. A weak trough will form over the Yucatan Peninsula during the evenings, move offshore the Peninsula to over the eastern Bay of Campeche in the mornings, then dissipate in the afternoons. CARIBBEAN SEA... Thunderstorms are generating along a trough reaching from central Cuba to 11N78W, just north of eastern Panama. Showers and thunderstorms are also starting to flare off the coast of Colombia near Barranquilla. A recent scatterometer satellite pass from 02 UTC indicated trade winds were already reaching 20 to 25 kt off the coast of Colombia, off the Guajira peninsula. Moderate to fresh trades are noted elsewhere east of the trough, supported by high pressure north of the area. Farther east, regional radar indicates a few fast moving trade wind showers through the Leeward and Windward Islands. The same scatterometer pass showed fresh to strong easterly winds just off the northern Leeward Islands. Seas east of the Leeward and Windward Islands are reaching 8 ft due to the persistent trade winds and a component of E to NE swell. Little change is expected in the forecast. The trough will drift slowly west through Thu then will dissipate. Moderate to fresh trades will persist east of the trough, with pulses of fresh to strong trade winds off northeast Colombia mainly at night. ATLANTIC OCEAN... A stationary front extends from 31N74W to near Abaco Island in the northern Bahamas. Fresh to strong southerly winds are embedded in a large area of scattered showers and thunderstorms active north of 29N within 120 nm of the dying front. Divergence aloft on the southeast side of an upper trough is also supporting showers and thunderstorms farther south near the Turks and Caicos Islands. Meanwhile the upper support for the front is lifting northward, and the front will dissipate through late today. This will allow the convection and related winds and seas to diminish accordingly. The remnants of the front will persist through Thu as a weak trough. Ridging building westward north of 27N in the wake of the dying front/trough will support moderate to fresh trades south of 22N west of 55W. Fresh to strong winds will pulse off the north coast of Hispaniola through Sat, mainly at night, due to a combination of the subtropical ridge to the north and local drainage flow. Farther east, A 1030 mb high centered near 35N46W dominates the central and eastern Atlantic. Latest observations indicate fresh trades covering much of the tropical N Atlantic waters S of 15N, with generally moderate winds N of 15N. The long fetch of fresh trades supports seas of 6 to 8 ft over those waters. The combination of trade wind convergence in the lower levels along with upper divergence south of an elongated upper ridge are supporting areas of active convection along the ITCZ farther south. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen