185 AXNT20 KNHC 201207 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 806 AM EDT Fri Jul 20 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 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...TROPICAL WAVES... A tropical wave is east of the Cape Verde Islands with axis extending from 05N-18N along 21W. Significant Saharan dry air and dust intrusion into the wave environment along with strong deep layer wind shear in the region have greatly reduced the convection associated with this wave. Isolated showers are confined to the region S of the monsoon trough from 05N-09N between 12W-23W. A tropical wave is in the central Atlantic with axis extending from 03N-16N along 37W, moving W at 15 kt. The wave is moving across an extensive Saharan Air Layer Outbreak with dry air and dust hindering convection. A low amplitude tropical wave is over the central Atlantic with axis extending from 02N-11N, moving W at 15 kt. No convection is associated with this wave at this time. A tropical wave is in the central Caribbean along 74W, moving W at 20 kt. The wave is in a strong deep layer wind shear environment. Scattered moderate convection is over Hispaniola. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from W Africa near 16N16W to 09N22W to 07N36W. The ITCZ begins near 07N40W and continues to South America near 05N52W. See tropical waves section for information on convection. ...DISCUSSION... GULF OF MEXICO... As of 20/0900 UTC, a 1012 mb low is centered off the Florida Panhandle near 30N86W. Widely scattered moderate convection is over the NE Gulf of Mexico N of 27N and E of 90W to include NW Florida. This convection is being enhanced by upper level diffluence to the S of an upper level trough centered N of Florida. A 1015 mb high is over the central Gulf near 24N89W. 10 kt anticyclonic surface winds are noted around this high. Expect the surface low to dissipate tonight, and a high pressure ridge to prevail over the Gulf along 25N through early next week. A surface trough will also move off the Yucatan Peninsula into the Bay of Campeche each evening, accompanied by fresh nocturnal winds. CARIBBEAN SEA... A tropical wave is over the central Caribbean. See section on tropical waves above. RGB imagery from GOES-16 shows a thin layer of Saharan Dust moving across the central and western portions of the basin. Expect the wave to move over the western Caribbean today. Scattered moderate convection is over the SW basin Sunday primarily due to the eastern extent of the E Pacific monsoon trough. Fresh to strong winds are expected to continue over the central basin through the weekend. Near gale force winds will be likely, however, along the coast of Colombia this weekend. ATLANTIC OCEAN... A 1034 mb Azores High is centered near 41N36W. A surface ridge axis extends SW to the W Atlantic near 28N70W. Widely scattered moderate convection is over the W Atlantic N of 28N and W of 70W, mostly due to upper level diffluence. Most of the central Atlantic N of 20N between 35W-65W has fair weather. For additional information please visit http://www.hurricanes.gov/marine $$ MRF/NAR