000 AXNT20 KNHC 100003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 PM EDT Sat Jun 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 21W/22W from 13N southward, moving westward 15 knots. The Hovmoller Diagram indicates the westward propagation of the wave, and model diagnostics guidance also suggests the presence of this system. This wave shows up well as a low amplitude moisture surge on the TPW product. Currently, convection is limited along the wave's axis due to the presence of African dust. A second Atlantic Ocean tropical wave extends its axis along 36W/37W south of 15N, moving westward 10 to 15 knots. Isolated moderate convection is seen where the waves axis meets the ITCZ. Saharan dust surrounds the wave. A Caribbean Sea tropical wave is along 63W/64W from 19N southward moving westward 15 to 20 knots. A patch of low level moisture with embedded showers is associated with the wave, affecting parts of the Lesser Antilles. The wave will pass to the south of Puerto Rico tonight, and reach Hispaniola on Sunday. A Caribbean Sea tropical wave is along 86W/87W from 19N southward, moving westward 10 knots. The wave is moving through an area of upper level cyclonic wind flow. Continued rainshowers are possible in parts of the western Caribbean Sea and northern sections of Central America. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through Guinea, and continues to 09N21W to 07N34W. The ITCZ stretches from 07N37W to 06N45W to the coast of Guyana near 08N59W. A cluster of moderate convection is from 6.5N-8N between 14N-16N. Similar convection is noted within about 120 nm N of the ITCZ axis between 52W and 57W. ...DISCUSSION... GULF OF MEXICO... A mid to upper level low located over the NE Gulf continues to enhance the development of scattered showers and thunderstorms across the eastern Gulf, and over parts of Florida. A surface trough is analyzed over northern Florida and the NE Gulf in association with this system aloft. The remainder of the Gulf is under the influence of a ridge anchored by a 1022 mb high pressure situated over central Florida. Scattered showers and tstms are also noted just of the coast of Mexico, roughly between Tampico and Veracruz, where a diffluent pattern aloft prevails. The middle to upper level cyclonic circulation center will meander in the eastern Gulf of Mexico through Tuesday, supporting rainshowers. A surface trough will develop along the Yucatan Peninsula late each afternoon, drift westward across the southwest Gulf during the overnight hours, then dissipate along 96W during the late mornings. Fresh northeast to east to southeast wind shift is expected in the vicinity of the trough. An east to west ridge will meander across the northern Gulf waters through the period accompanied by a moderate southeast return flow in the W Gulf. Fresh to strong winds and associated seas are expected in the Yucatan Channel Wed evening associated with a tropical wave or developing area of low pressure that will move into the SW Gulf Thu. CARIBBEAN SEA... Scatterometer data have been showing near gale force trade winds across the south-central Caribbean, particularly S of 13N between 73W and 77W. The most recent altimeter data indicated sea heights of near 14 ft in association with these winds. Fresh to strong trade winds area noted elsewhere from 11N- 17N between 68W- 80W. Moderate to locally fresh trades prevail across the remainder of the eastern Caribbean, with gentle to moderate NE-E winds across the NW part of the basin. The pressure gradient between high pressure N of area and the Colombian/Panamanian low will continue to support fresh to strong winds across the central Caribbean, and the eastern Caribbean S of 15N, but mainly W of 64W. These conditions will persist through at least Mon. The Saharan Air Layer (SAL) from CIMSS shows abundant Saharan dust covering the area between the west coast of Africa and the Lesser Antilles. The Saharan dust is expected to reach Puerto Rico and the Virgin Islands on Sun, bringing haze conditions across the area. A tropical wave will move west across the Gulf of Honduras through tonight. The wave interacts with an upper trough that supports the continuation of rainshowers across the NW Caribbean. A second tropical wave is in the E Caribbean supporting showers in the NE basin, including the Leeward Islands. Strong high pressure N of the area will support fresh to strong trades in the south-central basin continuing through Thu, however increasing in areal coverage Wed and Thu. A tropical wave is forecast to move across Honduras Tue night into Wed tightening the pressure gradient, thus resulting in fresh to strong winds in the Gulf of Honduras and NW Caribbean. ATLANTIC OCEAN... Abundant moisture continues to prevail across the west Atlantic, on the eastern side of the Gulf of Mexico-Yucatan Peninsula mid to upper-level trough. A band of multi-layer clouds extends from central Cuba across the NW and central Bahamas. Lightning data and Doppler Radar indicate the presence of tstms over S Florida and the NW Bahamas. A ridge dominates the remainder of the Atlantic Ocean with a 1027 mb high pressure located near 31N41W. Moderate to locally fresh winds are noted along the southern periphery of the ridge per scatterometer data. Surface ridging extending from the central Atlc will prevail across the region, thus supporting moderate ESE winds in the vicinity of the southern Bahamas. Fresh to locally strong nocturnal easterly winds are forecast to continue along the northern coast of Hispaniola through Sunday. These winds will resume Tue night and continue through Thu. Gentle to moderate southwesterly flow is expected N of 30N of the ridge. For additional information please visit http://www.hurricanes.gov/marine $$ MT