000 WTNT34 KNHC 020254 TCPAT4 BULLETIN Tropical Storm Isaias Advisory Number 20 NWS National Hurricane Center Miami FL AL092020 1100 PM EDT Sat Aug 01 2020 ...ISAIAS CONTINUES TO SLOWLY APPROACH THE SOUTHEAST FLORIDA COAST... SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...25.5N 79.1W ABOUT 80 MI...130 KM ESE OF FORT LAUDERDALE FLORIDA ABOUT 105 MI...165 KM SE OF WEST PALM BEACH FLORIDA MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NW OR 310 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...995 MB...29.39 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Boca Raton to the Volusia/Flagler County Line Florida * Bimini, the Berry Islands, and Grand Bahama Island A Storm Surge Watch is in effect for... * Jupiter Inlet to Ponte Vedra Beach Florida A Tropical Storm Warning is in effect for... * North of Ocean Reef to south of Boca Raton Florida * Lake Okeechobee * Volusia/Flagler County Line to Ponte Vedra Beach Florida A Tropical Storm Watch is in effect for... * North of Ponte Vedra Beach Florida to South Santee River South Carolina Interests elsewhere along the southeast and mid-Atlantic coasts of the United States should monitor the progress of Isaias. Additional watches or warnings may be required tonight or Sunday. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. Preparations to protect life and property should be rushed to completion. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. 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 1100 PM EDT (0300 UTC), the center of Tropical Storm Isaias was located near latitude 25.5 North, longitude 79.1 West. Isaias is moving toward the northwest near 9 mph (15 km/h). A general northwestward motion with some decrease in forward speed is expected for the next day or so, followed by a north-northwestward motion by late Sunday. A turn toward the north and north-northeast is anticipated on Monday and Tuesday with an increase in forward speed. On the forecast track, the center of Isaias will approach the southeast coast of Florida tonight and early Sunday and move near or along the east coast of Florida Sunday and Sunday night. On Monday and Tuesday, the center of Isaias will move from offshore of the coast of Georgia into the southern mid-Atlantic states. Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Some restrengthening is possible, and Isaias could regain hurricane strength early Sunday. Slow weakening is expected to begin Sunday night and continue through Monday. Tropical-storm-force winds extend outward up to 115 miles (185 km) from the center. A Weatherflow site in Morningside Park in Miami recently reported a wind gust to 41 mph (66 km/h). An unofficial observing station on Great Harbour Cay recently reported a wind gust of 40 mph (64 km/h). The minimum central pressure estimated from Air Force Hurricane Hunter observations is 995 mb (29.39 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Isaias 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. STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Jupiter Inlet to Ponte Vedra Beach FL...2-4 ft North Miami Beach to Jupiter Inlet FL...1-3 ft The deepest water will occur along the immediate coast near and to the right of the center, where the surge will be accompanied by large waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. A dangerous storm surge will raise water levels by as much as 3 to 5 feet above normal tide levels in areas of onshore winds in the Northwestern Bahamas. WIND: Hurricane and tropical storm conditions will continue over portions of the Northwestern Bahamas through Sunday morning. Hurricane conditions are expected to reach the coast within the hurricane warning area in Florida Sunday morning and will spread northward through Sunday night. Winds are expected to first reach tropical storm strength later tonight, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. Tropical storm conditions are expected within the tropical storm warning area in South Florida Sunday morning. Tropical storm conditions are expected in the warning area in northeast Florida by Sunday night, and are possible in the watch area from northeast Florida to South Carolina on Monday. RAINFALL: Isaias is expected to produce the following rain accumulations: Bahamas: 4 to 8 inches, with isolated maximum totals of 12 inches. Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches. Eastern Florida: 2 to 4 inches, with isolated maximum totals of 6 inches. Northeast Florida and coastal Georgia: 1 to 3 inches. Carolinas and the mid Atlantic, including the southern and central Appalachians: 2 to 5 inches, with isolated maximum totals of 7 inches. Southeast New York and much of New England: 2 to 4 inches, with isolated maximum totals of 6 inches. Heavy rainfall from Isaias could result in potentially life-threatening flash flooding in the Bahamas and flash and urban flooding along the East Coast of the United States. Minor river flooding and isolated moderate river flooding is possible across portions of the Carolinas and mid Atlantic. SURF: Swells generated by Isaias are affecting portions of Hispaniola, eastern Cuba, the Turks and Caicos, and the Bahamas. These swells will spread along the east coast of Florida and the southeastern United States coast through Sunday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.