Hurricane Isaac
Status: Closed
Pre-Landfall 5 | Summary
Posting Date: August 26, 2012, 6:20:00 AM
Current Conditions
Tropical Storm Isaac made landfall about 40 miles east of Guantanamo, Cuba, yesterday with sustained winds of 60 mph. The storm’s passage over the mountainous tip of Cuba did little to diminish its strength and Isaac exited the island with winds intact at 60 mph. The storm then proceeded to track along the island’s northern coast, keeping the strongest winds offshore but delivering heavy rainfall to Cuba's central and eastern provinces. As of today’s 8:00 a.m. EDT advisory from the National Hurricane Center (NHC), Tropical Storm Isaac is about 135 miles east-southeast of Key West, Florida, and is moving into the Florida Straits at 20 mph. A decrease in forward speed is expected over the next 48 hours. Maximum sustained winds have increased to 65 mph, with higher gusts, and further intensification is expected. Tropical storm force winds (>39 mph) currently extend outward from the center 205 miles. Thus Isaac remains a very large storm.Reported Impacts
Tropical Storm Isaac crossed Haiti’s southern peninsula early yesterday, August 25, causing further misery to a population that has still not recovered from the earthquake that devastated the country in 2010. Hundreds of the tents that hundreds of thousands of people still call home were ripped away by Isaac’s winds or damaged by downed trees. The majority, however, remained intact according to U.N. officials. Sheet metal roofs were peeled off homes and businesses. Photos show heavy street flooding—waist deep in some locations—and widespread downed trees and power lines. Haiti's national electricity supplier said that at one point 30 out of the country's 32 electricity grids were down. Four people are reported to have died from the effects of the storm and the mayor of Jacmel, the town nearest the landfall location, has suggested that that number may rise as flooding and mudslides continue. In the Dominican Republic, rivers overtopped their banks, washing out roads and bridges. An estimated 3,000 homes were flooded, according to reports, and at least 10 rural settlements were cut off by floodwaters. Nearly a million people were left without power. In both Haiti and the Dominican Republic, most of the damage is unlikely to be insured. In Cuba, authorities evacuated thousands of residents in advance of the storm’s arrival. High waves have washed away structures on the immediate coastline. In Baracoa, the country’s easternmost city (estimated population over 80,000), officials report that at least 50 homes were destroyed or heavily damaged. After crossing the eastern end of Cuba, Isaac tracked along the north coast of the country, just offshore. This means that most of Cuba was on the left, weaker side of Isaac. While further wind damage should not be a concern, the possibility of additional flooding remains an issue. Note, too, that some of the Bahamian islands impacted by last year’s Hurricane Irene are now within the reach of Isaac’s tropical storm force winds. Sturdy construction there, however, should keep damage to a minimum. Meanwhile, some energy operators in the Gulf of Mexico have begun shutting down offshore oil and gas rigs. BP Plc, the biggest Gulf producer, has said it would shut down its Thunder Horse platform, the world's largest.Forecast Track and Intensity
Data from Hurricane Hunter aircraft indicate that Isaac has strengthened only slightly overnight, possibly because the storm is battling with dry low- to mid-level dry air in the western side of its circulation. Sustained winds have risen to 65 mph and central pressure has dropped slightly to 995 mb. As Isaac moves into the Florida Straits and into the eastern Gulf of Mexico, conditions should be favorable for further intensification. Isaac is now expected to achieve hurricane intensity soon after crossing the Florida Keys, and there is a chance that it will become a Category 2 hurricane as it approaches the Gulf Coast. How much stronger Isaac will become will depend in part on the storm's track—that is, how much time it will spend over the warm waters of the Gulf of Mexico. The storm is currently expected to continue on a west-northwest or northwest direction for the next 48 hours as it tracks around a subtropical ridge. After that, the dynamical forecast models are in considerable disagreement. Some have Isaac continuing on in the same direction toward a possible landfall in Louisiana. Others, however, have Isaac making a northerly turn, which would bring it to the Florida Panhandle. The National Hurricane Center's forecast track is somewhere in between; it has shifted to the west since yesterday’s NewsALERT, putting it on a course that would bring it near to or into Mobile Bay, Alabama, on early Wednesday. The NHC has emphasized that there is, as yet, little confidence in the forecast track at this stage, however. AIR's Tropical Cyclone team continues to monitor Isaac closely and will provide additional information on the development and impacts of this storm as warranted by events.If current forecasts hold, ALERT subscribers will be notified tomorrow afternoon when pre-landfall event sets for Isaac’s impacts on onshore properties in the U.S. are available for download. .