000 AXNT20 KNHC 042346 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 746 PM EDT Thu Jul 4 2019 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 2319 UTC. ...TROPICAL WAVES... A tropical wave has an axis along 35W south of 17N, moving W around 10-15 kt. A cluster of moderate convection is observed behind the wave axis, and where the wave meets the monsoon trough. This convective activity covers from 05N-13N between 33W-36W. Some of the usual summertime African dust surrounds the wave based on GOES-R RGB Geocolor imagery and the Saharan Air Layer product from CIMSS. A well defined tropical wave is just E of the Lesser Antilles along an axis of 60W, south of 18N, moving W at 15-20 kt. The TPW product shows a large area of moisture just behind this wave. Scattered moderate convection is noted on either side of the wave axis from 10N-16N between 59W- 63W. This activity is forecast to impact the Lesser Antilles the rest of today, and Puerto Rico and the UK/US Virgin Islands on Fri, bringing enhanced showers and thunderstorms with gusty winds. Moisture associated with this wave will likely reach Hispaniola late Fri into Sat. In addition, this wave is forecast to strengthen the trades across most of the basin through Sat as it passes across the forecast area, then reach Central America Sun. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea-Bissau near 12N16W to 09N26W to 06N39W. The ITCZ continues from 06N39W to the border of Brazil and French Guiana near 04N52W. Aside from the convection associated with the tropical waves, scattered moderate convection is seen within about 120 nm S of the monsoon trough between 17W- 33W. Isolated showers are seen along the ITCZ between 40W-49W. GULF OF MEXICO... Deep-layered ridge prevails across the entire Gulf of Mexico. A surface high of 1018 mb is analyzed close to the mouth of the Mississippi River near 28N89W. Under the influence of this system, mainly light to gentle winds prevail, with gentle to moderate southeasterly winds in the western basin. A surface trough extends from near Tampa Bay, FL across the SE Gulf into western Cuba from 28N83W to 23N84W. Scattered moderate convection was seen along this trough off the coast of Tampa Bay but this activity has since dissipated. Numerous strong convection continues over Florida, mostly on land--although a cluster of thunderstorms in SW Florida is beginning to move over adjacent waters. Otherwise, tranquil weather prevails. Weak high pressure will dominate the region through the weekend and produce gentle to moderate anticyclonic winds across the Gulf. A weak frontal boundary will sink southward into the NE Gulf late Monday, then drift SE and linger through Tuesday, where broad low pressure may develop. CARIBBEAN SEA... A tropical wave is just E of the Lesser Antilles. Please see the Tropical Waves section for more details. Upper level cyclonic wind continues over the western Caribbean. This is helping give way to scattered moderate convection off of the Cayman Islands, Jamaica, and Cuba. Isolated thunderstorms can be seen across the Greater Antilles, although convection is suppressed across the eastern half of the Greater Antilles due to SAL moving into the area. Scattered moderate convection is also seen over the Lesser Antilles--see the tropical waves discussion for more detail. Otherwise, fresh to strong trades are seen in the south- central Caribbean off the coast of Colombia. Gentle to moderate trades are seen in the rest of the Caribbean, with the exception of the NW basin which has light winds. Fresh to strong tradewinds prevail across south central portions of the Caribbean this evening, as an active tropical wave is moving across the Lesser Antilles. Winds will strengthen across most of the basin through late Sunday as this tropical wave reaches along 75W Saturday morning, then reaches Central America Sunday. Fresh to strong trades and seas to around 8 ft will linger across the tropical N Atlc waters tonight through Friday behind the tropical wave. ATLANTIC OCEAN... A low is analyzed in the western Caribbean near 29N65W with a surface trough extending along it from 31N61W to 28N68W. Isolated showers are seen along the low, otherwise there is no significant convection associated with it. Another surface trough is analyzed from 30N72W to 27N73W, with scattered thunderstorms seen along this trough. Isolated thunderstorms are also seen in the central Bahamas. Surface ridging prevails across the rest of the basin from a 1027 mb high near 33N39W. The trough with the low in the western Caribbean, from an old frontal boundary, will drift NW and slowly dissipate through Friday. High pressure across the central Atlantic will then build westward and into the Bahamas and S Florida through the weekend. Fresh to strong winds are expected N of the Greater Antilles Friday and Saturday as an active tropical wave moves through the central Caribbean. For additional information please visit http://www.hurricanes.gov/marine $$ AKR