Hurricane Irene strengthens, heads for U.S. mainland

With sustained winds of 100 mph, Hurricane Irene is a Category 2 hurricane, and predicted to strengthen even more, possible into Category 3 by late Wednesday. This satellite image shows its position i/ NOAA

MIAMI—Hurricane Irene has strengthened into a Category 2 hurricane and is expected to strengthen further as it approaches the U.S. mainland, the National Hurricane Center said Tuesday.

In a bulletin, the Miami-based National Hurricane Center said Irene's sustained winds had reached nearly 100 mph with higher gusts, making the storm a Category 2 hurricane.

“Additional strengthening is forecast during the next 48 hours,” according to the bulletin, which said Irene could become a “major hurricane,” which means it would pack sustained winds of at least 111 mph, Tuesday or Wednesday.

“The NHC extended forecast for Irene has changed considerably over the last 24 hours,” said Newark, Calif.-based catastrophe modeler Risk Management Solutions Inc. in a commentary on the hurricane. RMS noted that the forecast has the hurricane passing about 150 miles east of Florida on a northerly track, “which sees the system make landfall in North Carolina the later part of the coming weekend.”

Track shifted

However, RMS also noted that the projected landfall location has shifted more than 300 miles east since landfall first was forecast, “which is a reflection of the high uncertainty associated with the extended forecast. The NHC cone of uncertainty around the track path at landfall covers Florida, Georgia, South Carolina and North Carolina.”

“Irene is forecast to strengthen to a major hurricane as it passes over warm ocean waters and continues to track in an area of low wind shear—conditions conductive for development,” Emily Paterson, associate cat response manager at RMS, said in the analysis. “Under the current forecast, Irene will be a major hurricane when it passes through the Bahamas, when it makes its closest pass to Florida, and at its forecasted landfall.”

Irene made landfall in Puerto Rico as a tropical storm early Monday and later strengthened into a hurricane, the first of the season.

According to Boston-based catastrophe modeler AIR Worldwide Corp., insured commercial, residential and automobile exposure is estimated at $3.1 billion in 2009 dollars in the Turks and Caicos Islands. In the southernmost Bahamas islands—Inagua, Mayaguana and Crooked Island—insured exposure in 2009 dollars is $218 million. AIR said in an analysis of the Hurricane Irene issued Tuesday. “However, these islands are relatively unpopulated, accounting for less than 0.50% of the total Bahamas population, as of 2010,” said AIR. “It should be noted that over the next few days, Irene will be moving into much more populated areas.”

Meanwhile, authorities ordered tourists to evacuate Okracoke Island on North Carolina's Outer Banks in preparation for Hurricane Irene. The island can be reached only by ferry.p>