000 AXNT20 KNHC 300605 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT Sun Jul 30 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...TROPICAL WAVES... A tropical wave is in the east Atlantic with axis extending from 17N32W to 06N33W, moving west at 10-15 kt within the last 24 hours. The wave is in a region of low vertical wind shear, but is being severely affected by Saharan dry air and dust intrusion to its environment. This dry air and dust are affecting mainly the central and nothern environment of the wave. Shallow moisture confined to the monsoon trough support scattered moderate convection from 06N to 10N between 32W and 43W. A tropical wave is in the central Atlc with axis extending from 18N45W to 05N45W, moving W at 15 kt within the last 24 hours. The wave is in a region of moderate to strong vertical wind shear, and continues to be severely affected by Saharan dry air and dust intrusion to its environment, which is limiting convection to scattered showers from 05N to 10N between 41W and 50W. A tropical wave is E of the Lesser Antilles with axis extending from 21N55W to 09N57W, moving west at 10-15 kt within the last 24 hours. The wave is in a moderate vertical wind shear environment and continues to be affected by Saharan dry air and dust intrusion to its environment, which is inhibiting the development of deep convection. Scattered to isolated showers are confined to the ITCZ region from 08N to 12N between 53W and 58W. A tropical wave is in the central Caribbean with axis extending from 20N74W to 11N74W, moving W at 20 kt within the last 24 hours. Water vapor imagery depict dry subsident air over the wave also noticed in the CIRA LPW imagery. Besides dry air, strong vertical wind shear is in the central Caribbean, which is influencing the lack of deep convection at this time. A tropical wave is moving across Honduras and El Salvador into EPAC waters. Its axis extends from 16N87W to 06N89W, moving W at 20-25 kt within the last 24 hours. Heavy showers and tstms are over the western half of Honduras and across El Salvador extending to the Gulf of Honduras S of 17N W of 85W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 18N16W to 12N23W to 09N39W. The ITCZ extends from 09N47W to 10N56W. Besides the convection mentioned in the Tropical Waves section above, numerous heavy showers and tstms are off the coast of W Africa potentially associated with a tropical wave. The area of this convection is from 07N to 15N between 17W and 25W. ...DISCUSSION... GULF OF MEXICO... A cold front is moving across the SE CONUS being supported by a deep layered trough aloft that extends to far W Atlc waters. A pre-frontal surface trough extends from SE Georgia along northern Florida to SE Louisiana coastal waters near 29N89W. Shallow moisture along the northern Gulf along with the aforementioned features support scattered showers and isolated tstms N of 28N E of 90W. The western basin is under the influence of a weak surface ridge anchored by a 1014 mb high near 26N91W that provides variable gentle to light winds. Westerlies of the same magnitude dominate over the eastern half of the Gulf. The front will dip south over the northern Gulf waters this Sunday morning and is forecast to stall over central Florida during Sunday night. Scattered heavy showers and tstms are expected over the NE and SE Gulf during this period. CARIBBEAN SEA... A tropical wave moving across Honduras is generating heavy showers extending to the Gulf of Honduras. A second tropical wave is moving over central Caribbean waters, however lacking deep convection. See tropical waves section above for further details. An upper level low persists over E Cuba supporting scattered showers and tstms over southern coastal and adjacent waters. This upper level low along with a broad ridge covering the W Caribbean generate diffluent flow aloft, which is supporting isolated showers and tstms in the Windward Passage and W Haiti coastal waters. Otherwise, the extension of the Pacific's monsoon trough is producing numerous heavy showers and tstms over the southwest Caribbean from 10N to 12N W of 79W. A new tropical wave will be entering the E basin Sunday with possible isolated showers. ...HISPANIOLA... Diffluent flow to the E of an upper-level low situated over E Cuba along with shallow moisture in the region support isolated showers and tstms across the Windward Passage and W Haiti coastal waters as well as southern Dominican Republic. Similar activity is expected to continue through Sunday night followed by some pockets of dry air that will support fair weather conditions early on Monday. ATLANTIC OCEAN... Diffluent flow aloft between a deep layer trough over the E CONUS, and a broad upper ridge anchored over Texas extending SE to the norther Bahamas support isolated showers N of 23N W of 71W while the upper low over E Cuba support scattered showers over the Great Bahama Bank. Three tropical waves are moving across the basin. See the section above for details. Otherwise, a broad surface ridge anchored by a 1029 mb high near 33N40W covers the remaining basin and supports fair weather. A cold front will move into SW N Atlc waters today with showers and fresh winds. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos