Questions and answers on Hurricane Irma’s impact on Florida

MIAMI — As Hurricane Irma is projected to be on a collision course with Florida on Saturday, one question lingers: Will the southwest or southeast part of the state receive the brunt of its Category 4 winds?

Irma's forecast track from the National Hurricane Center shifted west Friday toward Naples, which means the Florida Keys will be heavily impacted. While one side of the state’s southern peninsula is expected to received Irma's strongest winds, the other side may be getting Category 3 or 2 winds, said the center's acting director, Ed Rappaport.

"Where that Category 3 or 4 occurs is not clear," he said. "It could be on the east coast or west coast. It will be one or the other with the other one getting Category 2."

Southwest Florida and the Tampa area can expect life-threatening 6 to 12 feet of storm surge.

More:As Hurricane Irma approaches Miami, residents make one last trip to South Beach

More:Hurricane Irma: Where is the Category 4 storm now and where is it headed next?

Irma's western shift wasn't expected under the National Hurricane Center projections, but a 25-mile shift is well within a 100-mile margin of error two to three days before a storm, Rappaport said.

Under Friday's forecast, Category 3 winds are expected up to Lake Okeechobee, with the Treasure Coast north of West Palm Beach receiving Category 2 or 3 winds, Rappaport said. The hurricane will gradually weaken as it moves up to a Category 2 in Central Florida and Category 1 in North Florida.

Stronger winds in Central Florida would still be possible if the storm shifts east, and the threat of storm surge still is important, Rappaport said. About half of all hurricane victims drown.

Here are some of the questions our USA TODAY Network staff and readers asked during a Facebook Live interview Friday afternoon with Michael Brennan, chief hurricane specialist at the National Hurricane Centers.

When should you be 100% ready for Hurricane Irma (that includes putting up shutters, seeking shelter or evacuation if there's an order)?

If you live in Southwest Florida, by mid-afternoon Saturday. Tropical storm conditions arrive in the area Saturday evening.

If you live on the Treasure Coast, by Saturday evening. All areas south of Lake Okeechobee will see worse conditions Sunday morning to afternoon.

If you live north of Lake Okeechobee (Central Florida and Brevard County), you have all day Saturday, and tropical storm conditions could begin Sunday during the day.

Which areas are at greater risk of storm surge?

Southwest Florida, from Venice down the coast, covering Naples and could extend inland into Fort Myers and Port Charlotte. Of particular concern are Captiva and Cape Sable, which could experience 6 to 12 feet of above-ground water. 

Why should Southwest Florida be particularly concerned?

The center of Irma is moving very close to the Southwest coast, which is at risk of seeing core winds. You should prepare to see major winds of the hurricane, which can cause catastrophic damage as a Category 4 storm. "We are talking about building failures, roof damage, trees knocked down and severe damage to infrastructure," Brennan said.

Will Irma weaken as it moves up Florida?

Irma is expected to still be a hurricane by Monday but weaker along both coasts and in the core.

If the core moves east and close to the Atlantic coast, winds could be stronger. If it moves west and stays off shore, it won't weaken as fast as it would if it stayed in the Florida peninsula.

If it moves over the peninsula, it would weaken below a major hurricane, which is a Category 3. But remember, that’s still a major event and storm surge still is a concern.