621 AXNT20 KNHC 260605 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT Thu Jul 26 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...TROPICAL WAVES... A tropical wave came off the W coast of Africa yesterday evening. The wave axis is E of the Cape Verde Islands along 20W from 07N to 18N. The wave is in a moderate deep layer wind shear environment and underneath diffluent flow aloft. This along with shallow moisture S of the Cape Verde Islands is supporting scattered showers and tstms from 06N to 12N E of 22W. The remainder wave environment lacks convection due in part to the presence of Saharan dry air and dust. A tropical wave is over central Atlantic with axis along 35W extending from 06N-19N, moving westward at 10-15 kt. A large area of Saharan dry air and dust continue to hinder convection from developing at the time. A tropical wave is over the central Atlantic with axis along 49W from 05N-16N, moving westward at 10-15 kt. Strong deep layer wind shear and Saharan dry air and dust hinder deep convection at the time. Shallow moisture and middle level diffluence support isolated showers and tstms mainly ahead of the wave near the ITCZ from 09N-11N between 50W-59W. A tropical wave is over the central Caribbean with axis along 71W from 08N-20N, moving westward at 15 kt. CIRA LPW imagery show a very dry environment across the central Caribbean, which along with strong deep layer wind shear hinder convection S of Hispaniola. Shallow moisture and middle level diffluence support scattered showers and tstms ahead of the wave in the Windward Passage...off SW Haiti. A tropical wave has moved inland the Yucatan Peninsula, Belize and into EPAC waters. Its axis is along 89W, moving W at 10-15 kt. Except for El Salvador and the EPAC waters, there is no convection associated with this wave. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Africa near 14N17W to 12N31W. The ITCZ extends from 09N38W to 09N45W...then resumes W of a tropical wave near 09N52W and continues to the coast of South America near 08N59W. For information on convection, see the tropical waves section. ...DISCUSSION... GULF OF MEXICO... An upper level trough prevails across the E Gulf with base extending SW to the Bay of Campeche, which supports a weak cold front that across the Florida Panhandle to SE Louisiana. It also supports a surface trough that extends from the Florida Big Bend SW to 24N88W. Isolated showers are within 75 nm ahead of this trough. The trough is forecast to dissipate today while the front lift NE of the area. Otherwise, the Atlantic subtropical ridge covers the remainder SE Gulf and will continue to progress westward across the remainder basin through the weekend. Light to gentle variable flow will dominate across the basin during this period. CARIBBEAN SEA... An upper level low centered near Jamaica, middle level diffluence along with shallow moisture in the NW Caribbean support scattered showers and tstms N of 17N between 73W and 81W. In the SW basin, the monsoon trough supports isolated showers and tstms S of 11N. GOES-16 water vapor imagery show very dry conditions across the remainder of the basin while an enhanced RGB show a thin layer of Saharan Air Dust moving across the area. Strong deep layer wind shear is also noted in the E Caribbean. These hostile factors are suppressing convection elsewhere. Otherwise, a tropical wave moves over central Caribbean waters. See the waves section above for further details. A new tropical wave is forecast to move across the Lesser Antilles Friday night. ATLANTIC OCEAN... Three tropical waves are moving across the basin lacking convection due in part to the presence of the dry air in the Saharan Air Layer. Refer to the tropical waves section above for more details. Scattered showers and tstms are N of the Bahamas W of 76W being supported by an upper trough along the E CONUS extending to W Atlc waters. Farther east, an upper level low supports a surface trough along 27N62W to 19N66W which generates isolated showers and tstms N of 25N between 61W-66W. Otherwise, the Atlantic subtropical ridge dominates the remainder basin being anchored by a 1031 mb high centered near 36N55W. 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 $$ Ramos