479 AXNT20 KNHC 251717 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 117 PM EDT Wed Jul 25 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...TROPICAL WAVES... A tropical wave is over the far eastern Atlantic west of the Cape Verde Islands with axis along 34W extending from 05N-19N, moving westward at 15-20 kt. A large area of Saharan dry air and dust is hindering convective activity from developing at the time. A tropical wave is over the central Atlantic with axis along 46W from 04N-15N, moving westward at 15-20 kt. A large area of Saharan dry air and dust is hindering convective activity from developing at the time. A tropical wave is over the eastern Caribbean with axis along 62W from 08N- 19N, moving westward at 15 kt. A large area of Saharan dry air and dust is hindering convective activity from developing at the time. A tropical wave is over the western Caribbean with axis along 81W from central Cuba to central Panama, moving westward at 15-20 kt. Shallow moisture in the northern wave environment along with a region of middle to upper level diffluence east of the wave is supporting isolated moderate convection off the coasts of E Cuba and Jamaica. In addition, scattered moderate convection is over the southern portion of the wave along the coasts of Panama and Costa Rica S of 11N. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Africa near 11N15W to 09N20W to 10N34W to 08N37W. The ITCZ extends from 08N37W to 08N45W. The ITCZ resumes W of a tropical wave near 08N48W and continues to the coast of South America near 07N58W. Scattered moderate convection is along the coast of W Africa from 07N-12N between 13W-21W. ...DISCUSSION... GULF OF MEXICO... An upper level trough is over the NE Gulf of Mexico and N Florida. This feature supports a 1013 mb surface low near 30N86W. Diffluence aloft east of the upper level trough is sustaining convection over the W Atlantic off the Florida coast, while diffluence to the south is producing convection over the south central Gulf of Mexico. Convection is expected to continue over these areas through Thu. The Atlantic subtropical ridge will then extend an axis SW across the eastern Gulf. Surface ridging is forecast to continue through the weekend, thus providing light to gentle variable flow across the basin. Elsewhere, a surface trough will move off the Yucatan Peninsula into the Bay of Campeche each evening, accompanied by fresh nocturnal winds. Scattered to isolated showers are possible in the Bay of Campeche with the surface trough. CARIBBEAN SEA... Two tropical waves are over the Caribbean. See above. Scattered moderate convection is over N Colombia, Panama, and Costa Rica. Isolated showers are located over waters S of Puerto Rico and Hispaniola between 65W and 75W. These showers are being sustained by a small region of shallow moisture and diffluence aloft. Relatively dry and stable conditions persist elsewhere. Expect the surface pressure gradient to support fresh to strong winds in the south-central basin through Fri. Elsewhere, stable conditions with light to moderate winds are expected. ATLANTIC OCEAN... Two more tropical waves are moving across the basin lacking convection due to the presence of the dry air in the Saharan Air Layer. Refer to the tropical waves section above for more details. Scattered moderate convection is across the W Atlantic including the northern Bahamas, W of 75W. Farther east, a middle to upper level low supports an area of scattered moderate convection from 22N-28N between 56W-64W. Otherwise, the Atlantic subtropical ridge dominates the remainder basin being anchored by a 1031 mb high centered near 37N55W. Expect convection north of the Bahamas through the weekend. Thesurface pressure gradient between the Atlantic 1031 mb subtropical high and the low pressure over the southeast U.S. will produce moderate to fresh southerly winds across the waters north of 25N and west of 70W including Florida coastal waters today. Moderate to fresh winds are also expected south of 22N, including approaches to the Windward Passage. Surface ridging will dominate the central and eastern Atlantic through the end of the week providing stable and dry conditions. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa