000 AXNT20 KNHC 050003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 PM EDT Fri Aug 4 2017 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 2345 UTC. ...SPECIAL FEATURES... A tropical wave is several hundred miles southwest of the Cabo Verde Islands associated with a 1010 mb center of low pressure located near 09N30W. The wave axis extends from 19N33W to the low pressure center, and has been moving west at 5 kt within the last 24 hours. The wave is in a region of low vertical wind shear, however some Saharan dry air and dust is observed entering the wave environment. CIRA LPW imagery show mainly a moderate moist environment with some patches of dry air. Convection is confined to the vicinity of the monsoon trough as scattered moderate with isolated tstms from 07N to 12.5N between 24W and 40W. There is a medium chance for this system to become a tropical depression by early next week across the eastern or central tropical Atlc. ...TROPICAL WAVES... A tropical wave is in the central Atlc with axis extending from 20N44W to 11N44W, moving west at 5 kt within the last 24 hours. The wave is in a region of low vertical wind shear, however intrusion of Saharan dry air and dust to its environment is inhibiting any significant deep convection at this time. A tropical wave is in the central Caribbean with axis extending from 18N71W to 10N71W, moving west at 10 kt within the last 24 hours. The wave is in a region of strong vertical wind shear, however shallow moisture and upper level diffluence support scattered to isolated showers from 14N to 20N between 61W and 74W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 13N17W to 12N25W to 09N34W to 12N41W. The Intertropical Convergence Zone axis extends from 11N47W to 08N55W to 09N60W. Aside from convection associated with the tropical waves...scattered moderate convection is from 08N to 11N east of 19W and from 07N to 14N between 49W and 60W. ...DISCUSSION... GULF OF MEXICO... A middle to upper level trough is noted on water vapor imagery over the SE CONUS with the base of the trough extending over the north-central and NW Gulf waters. The troughing continue to support a surface trough extending from Alabama near 31N86W SW to inland Texas near 28N98W. Low-level moisture convergence along this boundary along with divergent flow aloft generated by the eastern periphery of a broad upper ridge anchored over NW Mexico support scattered showers and isolated tstms mainly N of 26N E of 95W. The boundary is expected to remain nearly stationary through Saturday night, then it is forecast to lift northward and dissipate Sunday. Otherwise, surface ridging prevails across the remaining basin being the support for generally fair weather conditions and gentle to light southerly flow. No major changes expected through Monday of next week. CARIBBEAN SEA... A tropical wave is moving across the central Caribbean generating a broad area of scattered to isolated showers generally N of 14N E of 74W. Fresh to strong winds are in the vicinity of this wave forecast to persist as the wave continue to move westward during the weekend. Numerous heavy showers and scattered tstms are within 135 nm off the coast of Colombia between 71W and 76W with possible gusty winds. In the NW basin, upper level diffluent flow along with abundant moisture in the region, as depicted by the CIRA LPW imagery, support scattered showers and tstms N of 14N W of 77W. ...HISPANIOLA... Scattered to isolated showers and tstms are occurring across the Island mainly S of 19N, including southern adjacent waters to 14N. This shower activity is associated with a tropical wave that moves over central Caribbean waters tonight. The tropical wave is expected to be W of the island by Saturday night, however shower activity is forecast to linger through early Sunday morning. ATLANTIC OCEAN... A tropical wave several hundred miles SW of the Cape Verde Islands has a medium chance of becoming a tropical cyclone during the next two days. See special features for further details. Otherwise, the remainder Atlc is under the influence of a surface ridge anchored by two 1024 mb highs...one near 28N69W and another near 29N51W, which are forecast to stall during the next 24 hours. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos