Aides say McCain and his wife Cindy will join Palin in traveling to Jackson, Miss., Sunday at the invitation of Mississippi Gov.
Haley Barbour because of concerns about people threatened by the storm, which was heading into the Gulf of Mexico and menacing the same area ravaged by Hurricane Katrina three years ago. The storm could hit the United States as early as Monday afternoon.
The McCains and Palin will receive a briefing at the Mississippi Emergency Management Agency - a permanent operations center monitoring hurricane response.
Republicans are worried about holding their national convention during the storm.
If the storm's landfall is serious, McCain said he probably would rethink allowing the four-day political gathering to continue.
"It just wouldn't be appropriate to have a festive occasion while a near tragedy or a terrible challenge is presented in the form of a natural disaster," McCain said in an interview taped Saturday with "Fox News Sunday." "So we're monitoring it from day to day, and I'm saying a few prayers, too."
President Bush was criticized after Katrina struck in August 2005 because he stuck to a schedule that took him from his ranch in Texas on a two-day trip to Arizona and California. There, he promoted a Medicare proposal while making just scant references to Katrina even as it slammed the Gulf Coast. Bush even happily strummed a guitar backstage at one event. He did not return to Washington until two days after the storm and did not visit the region until five days after.
The Bush White House was badly burned by its fumbling response after Katrina. Bush's image as a strong leader has never entirely rebounded, even though he has labored to improve on the Katrina performance.