 National Hurricane Center's Michael Brennan says it is a powerful Cat 4 storm. We're most concerned about areas from St. Vincent and the Grenadines south to Grenada, where we could see the core of that Category 4 hurricane move through. When you get to Category 4 strength, you can see things like total roof damage, roofs lifted off of homes, exterior wall collapse, trees uprooted, significant damage and complete destruction of power lines and other infrastructure.