256 AXNT20 KNHC 261203 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...TROPICAL WAVES... A tropical wave is near the Cabo Verde Islands with an axis extending from 10N21W to 07N21W, moving westward at 10 to 15 kt. This wave is well defined with a notable 700 mb trough in model guidance. Deep moisture interacting with the wave S of 12N is generating scattered moderate convection from 07N to 12N between 18W and 24W. 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 an axis extending from 20N35W to 07N36W, moving westward at 10 to 15 kt. A large area of Saharan dry air and dust continue to hinder convection from developing around this wave. A tropical wave is over the central Atlantic with an axis extending from 18N49W to 05N50W, moving westward at 10 to 15 kt. Strong deep layer wind shear and Saharan dry air and dust are hindering deep convection at this time. A tropical wave is over the central Caribbean with an axis extending from 21N71W to 11N73W, moving westward at 15 to 20 kt. Precipitable water satellite imagery shows a very dry environment across the central Caribbean, which along with strong deep layer wind shear are hindering convection S of Hispaniola. Only shallow moisture and middle level diffluence support scattered showers and tstms ahead of the wave in the Windward Passage...off SW Haiti. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Africa near 12N16W to 09N32W. The ITCZ extends from 09N37W to 08N48W...then resumes W of a tropical wave near 09N52W and continues to the coast of South America near 09N61W. Aside from convection associated with the tropical waves, scattered moderate convection is from 06N to 11N E of 18W, and within 150 nm N of the ITCZ axis between 52W and 60W. ...DISCUSSION... GULF OF MEXICO... An upper level trough prevails across the E Gulf with base extending SW from central Florida to the Bay of Campeche. This trough supports a weak stationary front that extends across the Florida Panhandle to SW Louisiana. It also supports a surface trough that extends from the Florida Big Bend SW to 24N89W. Isolated showers and tstms are within 75 nm SE of this trough. The trough is forecast to dissipate today while the front lifts NE of the area. Otherwise, the Atlantic subtropical ridge covers the remainder SE Gulf and will continue to build northwestward across the remainder basin through the weekend. Light to gentle variable flow will dominate the basin during this time period. CARIBBEAN SEA... An upper level low centered near Jamaica along with shallow moisture in the NW Caribbean support scattered showers and tstms N of 17N between 72W and 82W. In the SW basin, the monsoon trough supports scattered showers and tstms S of 11N. A tropical wave is crossing the central Caribbean waters. See the tropical waves section above for further details. GOES-16 water vapor imagery indicates very dry conditions across the remainder of the basin while enhanced RGB satellite imagery indicates 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 across the remainder of the Caribbean basin. A new tropical wave is forecast to move across the Lesser Antilles Friday night. ATLANTIC OCEAN... Three tropical waves are moving across the basin. Please 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 eastern United States that extends to the W Atlc waters. Farther east, an upper level low supports a surface trough that extends from 27N62W to 23N67W which is supporting isolated showers and tstms N of 25N between 61W and 68W. Otherwise, the Atlantic subtropical ridge dominates the remainder of the basin being anchored by a 1031 mb high centered near 36N56W. 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 $$ Latto