000 WTNT34 KNHC 290541 TCPAT4 BULLETIN Potential Tropical Cyclone Nine Intermediate Advisory Number 3A NWS National Hurricane Center Miami FL AL092020 200 AM AST Wed Jul 29 2020 ...HEAVY RAINFALL AND GUSTY WINDS AFFECTING THE LESSER ANTILLES... SUMMARY OF 200 AM AST...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...14.9N 60.3W ABOUT 50 MI...80 KM ENE OF MARTINIQUE ABOUT 450 MI...725 KM ESE OF SAN JUAN PUERTO RICO MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 25 MPH...41 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Puerto Rico, Vieques, Culebra * U.S. Virgin Islands * British Virgin Islands * Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla * Guadeloupe, Martinique, St. Martin, and St. Barthelemy * Saba and St. Eustatius * St. Maarten * Dominica * Dominican Republic from Cabo Caucedo eastward to Cabo Engano and then westward along the northern coast to the Dominican Republic/Haiti border A Tropical Storm Watch is in effect for... * Dominican Republic from the southern Haiti border eastward to Cabo Caucedo * Turks and Caicos Islands Interests elsewhere in the southeast and central Bahamas should monitor the progress of this system. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM AST (0600 UTC), the disturbance was centered near latitude 14.9 North, longitude 60.3 West. The system is moving toward the west-northwest near 25 mph (41 km/h), and this general motion with some slight reduction in forward speed is expected over the next few days. On the forecast track, the center will move through the southern Leeward Islands during the next few hours, near or over the Virgin Islands and Puerto Rico Wednesday night, and near or over Hispaniola on Thursday. Maximum sustained winds are near 45 mph (75 km/h) with higher gusts. Some strengthening is expected during the next 48 hours, and the system is forecast to become a tropical storm today. Environmental conditions are expected to be conducive for additional development, and a tropical storm is forecast to form later today. * Formation chance through 48 hours...high...90 percent * Formation chance through 5 days...high...90 percent Tropical-storm-force winds extend outward up to 230 miles (370 km), north of the center. The estimated minimum central pressure based on Air Force Reserve Hurricane data is 1006 mb (29.71 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Potential Tropical Cyclone Nine can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml. WIND: Tropical storm conditions are expected to reach the Leeward Islands during the next few hours, and spread across the U.S. and British Virgin Islands and Puerto Rico this afternoon through Thursday morning. These conditions are forecast to reach portions of the Dominican Republic within the warning area early Thursday. Tropical storm conditions are possible in the watch areas on Thursday. RAINFALL: The potential tropical cyclone is expected to produce the following rain accumulations: Across the northern Leeward Islands, British and U.S. Virgin Islands: 3 to 6 inches. Across Puerto Rico: 3 to 6 inches, with isolated maximum totals of 10 inches. Across the Dominican Republic: 3 to 6 inches, with isolated maximum totals of 8 inches. These rainfall amounts could lead to life threatening flash flooding and mudslides, as well as potential riverine flooding. Rainfall is also expected in the following locations: Across the Windward Islands: 1 to 3 inches. SURF: Swells generated by Potential Tropical Cyclone Nine will be affecting portions of the Leeward Islands, the Virgin Islands and Puerto Rico during the next day or two. These dangerous conditions are forecast to reach the north coast of the Dominican Republic and the Turks and Caicos Islands and the southeastern Bahamas on Thursday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 500 AM AST. $$ Forecaster Blake