Tropical storm Isaac is located in the Gulf of Mexico and is heading towards the coast of Louisiana. In the last 24 hours, Isaac’s wind field has expanded even further and the storm now has a total diameter of 580 miles. This means that when Isaac makes landfall, a very large area of coastline, and inland, is likely to be impacted.
– Landfall is expected within the next 48 hours, however there is an unusually large uncertainty associated with the landfall location. The forecast uncertainty cone extends from the Texas/Louisiana border east to the Mississippi/Alabama border.
– Further intensification is expected as Isaac approaches the Gulf coast and the NHC are calling for Isaac to be a category 1 hurricane at landfall. Hurricane warnings are in place from Morgan City, Louisiana to Destin, Florida. This includes the Metropolitan areas of New Orleans and Baton Rouge in Louisiana with populations greater than 1 million and 800,000 respectively, as well as Mobile, Alabama and Pensacola, Florida, both with populations slightly below half a million.
– Storm surge and heavy rainfall are other hazards that have the potential to impact the landfall area. The NHC are warning that storm surge could reach 6 to 12 ft in southeast Louisiana and Mississippi.
– Isaac was located approximately 85 miles from the southwest coast of Florida when it track past the coast on Sunday. Preliminary wind field analysis (as of 09:00 UTC on Monday, August 27) indicates that southern Florida, including Fort Lauderdale and Miami, were within the tropical storm force wind field of Isaac but Tampa was not. The western Florida Keys experienced strong tropical storm force winds. Early reports from Florida indicate that there was little wind damage and power outages have been relatively minor.
On Tuesday 21 August, the ninth named storm of the 2012 Atlantic Hurricane Season Isaac was declared. Isaac developed from a tropical depression to the east of the Lesser Antilles. The system tracked over the southern part of the Lesser Antilles late (UTC) on Wednesday, August 22/ early (UTC) on Thursday, August 23 as a tropical storm with the center of circulation passing south of Guadeloupe. Preliminary wind field analysis indicates that Antigua and Barbuda, Guadeloupe and St Kitts and Nevis were within
Isaac’s tropical storm force wind field as the system tracked through the southern Leeward Islands of the Lesser Antilles. Isaac then tracked west –northwest across the Caribbean Sea towards Hispaniola, where it tracked over the Haiti’s southern peninsula early (UTC) on Saturday, August 25. The system then emerged over the Windward Passage (between Cuba and Haiti) and tracked over extreme southeastern Cuba, before skirting the northeast coast of Cuba.
“The average date of formation of the ninth Atlantic storm between 1950 and 2011 is 24th September, and between 1995 and 2011 is 14th September,” said Margaret Joseph, catastrophe analyst at RMS. “Isaac forming prior to these dates indicates that, to date, in 2012 activity is currently above average. The earliest named ‘I’ storm was Irene in 2005, which formed on August 4.”
Isaac formed one year and one day after Irene in 2011, and like Irene Isaac is forecast to make landfall over the U.S. as a hurricane. Irene in 2011 was retired from the WMO Atlantic storm naming list. Since 2001 seven I storms have been retired.
