Hurricane Isaac
Status: Closed
Pre-Landfall 3 | Summary
Posting Date: August 24, 2012, 10:20:00 AM
Tropical Storm Isaac is moving westward through the eastern Caribbean Sea toward the island of Hispaniola, which comprises the Dominican Republic and Haiti. As of the National Hurricane Center’s (NHC) 11:00AM EDT Advisory, Isaac is located 165 miles south-southwest of Santo Domingo and is heading toward the west northwest at 14 miles per hour. The center of Tropical Storm Isaac is expected to pass over the westernmost end of Hispaniola on the Haiti side of the Haiti/Dominican Republic border Friday afternoon.
According to reports from an air force reserve hurricane hunter aircraft, the maximum sustained winds have increased to near 60 miles per hour with higher gusts. Tropical storm force winds (>39 mph) extend outward from the center an impressive 185 miles. Flight data also indicate that the storm remains poorly organized and, as a result, may strengthen only slightly before landfall. However, recent passes by the hurricane hunter aircraft indicates that organization is improving.
Exposure at Risk
Today’s passage of Tropical Storm Isaac on the Haiti side of the Haiti/Dominican Republic border diminishes the threat of significant damage to the Dominican Republic. Still, the flooding threat remains in effect especially in rural areas, where construction quality is typically of a lower standard, with unreinforced masonry and wood. These types of structures, though less likely to be insured, are most vulnerable to significant damage from flood, which can compromise structural walls and lead to loss of contents. In Haiti, while Port-au-Prince generally remains in disrepair from the 2010 earthquake, buildings in other cities and the countryside are of poor construction and subject to damage by heavy rains, flooding, and mudslides.Forecast and Intensity
Tropical Storm Isaac is expected to continue toward the west-northwest as it passes over Hispaniola Friday afternoon. It will then likely turn toward the northwest Friday night and pass near or over Cuba on Saturday. The path of the storm from that point on is uncertain at this time. The longer the storm spends over the islands of Hispaniola and Cuba, the more it will weaken, given the high terrain of those islands. Assuming it survives the passage over Cuba, it should reintensify over the warm waters of the Gulf of Mexico. It would likely be of tropical storm intensity as it passes over the Florida Keys, but it could make landfall anywhere from Florida to Louisiana by early Wednesday morning as a Category 1 or 2 hurricane. Currently, the primary hazard from the storm is flooding, flash floods and mud slides. Total rainfall accumulations of 8 to 12 inches with up to 20 inches are possible in Hispaniola. The very tall mountains on Hispaniola will enhance the possibility of heavy precipitation and flood damage, even as they will break up the storm’s circulation. Rainfall amounts of 4 to 8 inches with maximum amounts of 12 inches are possible across eastern Cuba and Jamaica. A storm surge will raise water levels by as much as 1 to 3 feet above normal tide levels along all coasts experiencing onshore winds in the tropical storm warning area. Dangerous surf and rip currents will affect the Leeward and Virgin Islands, Puerto Rico, Hispaniola, the Southeastern Bahamas, Turks and Caicos, and Cuba. AIR's Caribbean Tropical Cyclone team will be monitoring Isaac closely during the next few days and will post additional information on the development and impacts of this storm. The AIR U.S. Hurricane team is also analyzing Isaac’s potential threat to the U.S. Loss estimates for the U.S. may be made available to ALERT subscribers as early as Monday, depending on Isaac’s progress.