After dropping heavy rains on the Caribbean Islands over the weekend, Hurricane Earl now is headed towards the East Coast of the United States with the possibility of hitting the Carolinas by Thursday.

Earl was upgraded to a Category 4 storm on Tuesday by the National Hurricane Center, generating sustained winds of 135mph and gusts of up to 160mph.

A day earlier, Earl brought travel disruptions to Puerto Rico and the Virgin Islands, causing flights cancellations and diverting cruise ships.

Hurricane watches for the Caribbean are now cancelled although warnings for the East Coast could be issued as early this afternoon, according to forecasters.

The Federal Emergency Management Agency (FEMA) has already deployed teams throughout cities on the East Coast in anticipation of the storms.

"We're talking to the states, if they're going to even have to start talking about evacuating, we have people designated to help them," FEMA Administrator Craig Fugate, told the Associated Press.

FEMA's advanced response to Earl is evidence of federal reforms that took place following 2005's Hurricane Katrina, the fifth anniversary for which was observed this Sunday.

One of the deadliest storms to hit the U.S. in history, Katrina made landfall on the Gulf Coast as a Category 3 storm, killing almost 2,000 people and causing an estimated $81 billion in damage.

The large amount of damage was attributed in part to the federal government's delayed response.

In his proclamation to mark National Preparedness Month, which begins on September 1, President Barack Obama said that in remembrance of Katrina, the country must reaffirm its "commitment to readiness and the necessity of preparedness."

"My Administration has made emergency and disaster preparedness a top priority, and is dedicated to a comprehensive approach that relies upon the responsiveness and cooperation of government at all levels, the private and nonprofit sectors, and individual citizens," Obama said.

The president also encouraged Americans to visit the websites Ready.gov and CitizenCorps.gov which offer information and resources on emergency preparedness, including how to prepare a family emergency plan, create an emergency supply kit, and get involved in community preparedness efforts.