000 AXNT20 KNHC 300545 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 145 AM EDT SAT JUL 30 2016 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...SPECIAL FEATURES... A tropical wave is moving across the eastern Atlantic with axis that extends from 18.5N28W to a 1010 mb low near 12N26W. These features are moving west at about 10 kt. The wave is associated with a low to mid-level trough extending northward to the west of the Cabo Verde Islands along 27W. An earlier scatterometer pass indicated strong southwest to west winds converging into the low, supporting scattered moderate convection from 09N to 11N between 25W and 28W. This area has a medium potential for tropical cyclone development during the next 48 hours. ...TROPICAL WAVES... A tropical wave is moving across the central Atlantic with axis from 19N49W to 10N49W, moving west at about 15-20 kt. The tropical wave is evident as a broad and amplified low to mid level trough between 45W and 55W with abundant deep-layer moisture in SSMI Total Precipitation Water Vapor Imagery and satellite derived winds. Recent scatterometer data depicts broad surface troughing in the same vicinity. The gradient between the trough and the subtropical ridge to the north is resulting in fresh to strong trade winds from 13N to 22N between 45W and 55W, with associated seas to 9 ft. The trade winds convergence is also supporting scattered moderate convection from 14N to 16N between 47W and 55W. As this wave moves west during the next several days, fresh trades accompanied by potentially higher gusts will move across the waters north of the Greater Antilles and waters surrounding the Turks and Caicos, southeast Bahamas, and eastern and central Cuba creating hazardous boating conditions. A tropical wave is moving across the Bay of Campeche in the southwest Gulf of Mexico with axis extending from 21N91W to 18.5N93W, moving west at 10 to 15 kt. This is coinciding with the local evening surface trough that forms off the west coast of Yucatan. The tropical wave is expected to gradually weaken over the next 24-36 hours while enhances convection across the Yucatan Peninsula, southern Mexico and the Bay of Campeche. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 22N17W to the 1010 mb low pressure near 12N26W mentioned in the special features section, then continues westward to 10N50W. The intertropical convergence zone extends from 10N50W to 09N60W. Aside from the convection related to the tropical waves and the low pressure, scattered moderate convection is observed within 120 nm south of the monsoon trough between 35W and 50W. ...DISCUSSION... GULF OF MEXICO... A sharply elongated upper low remains centered along the coast of the northern Mexican state of Tamaulipas. Divergence aloft on the eastern side of the upper low was enhancing convection in the Bay of Campeche related to the tropical wave/trough early in the evening, but this has since weakened. Otherwise deep layer ridging dominates the region, the subtropical ridge reaching from the western Atlantic across Florida into the eastern Gulf of Mexico. This will maintain gentle to moderate breezes across the basin with 2 to 4 ft seas through early next week. CARIBBEAN SEA... An upper-level trough extending from over Haiti to the southwest Caribbean is delivering a plume of deep layer moisture across the east central Caribbean into the Virgin Islands, Puerto Rico and Hispaniola. An associated surface trough shows up well on recent Rapidscat data across the central Caribbean from just east of Cabo Beata on the south coast of Hispaniola to the Gulf of Venezuela. A line of showers and a few thunderstorms are active from the coast of Colombia to the Mona Passage. Fresh to strong trade winds are noted on west of the surface trough, off the coast of Colombia. Fresh trades are also noted across the Leeward Islands into the northeast Caribbean on the east side of the surface trough. The Leewards and northernmost Windward Islands and surrounding waters are in a relative dry slot currently between the upper trough to the west and the approaching tropical wave, but will see increased moisture and convection through today ahead of the approaching tropical wave. Little change is expected elsewhere. ...HISPANIOLA... Divergence aloft and increased moisture on the east side of an upper trough moving westward across Haiti will support scattered mainly afternoon convection. ATLANTIC OCEAN... Two tropical waves are moving across the tropical Atlantic. Please refer to the section above for details. A few showers and thunderstorms are active currently over the far western Atlantic from Hispaniola to the northern Bahamas, largely due to divergent flow aloft between an upper trough reaching from southwest of Bermuda to Haiti and an upper ridge farther to the northwest. Meanwhile a 1018 mb surface high is centered off Abaco Island near 27N77W. To the east, an upper-level trough is reflected at the surface as a trough that extends from 24N68W to Hispaniola. Another surface ridge extends across the remainder of the basin anchored by a 1030 mb high centered near 40N33W. Farther east, fresh to strong northeast winds are observed across the Canary Islands, between the ridge and lower pressure over northwest Africa. Little change is expected through the next 24 hours. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen