Barbour says all lanes of Interstate 59 from the Louisiana state line to Poplarville will be northbound. He says all lanes of Interstate 55 from the Louisiana state line to Bogue Chitto will be northbound.
Barbour says southbound traffic will be re-routed.
Barbour warned residents of south Mississippi that while the track for Gustav takes it west of Louisiana, past hurricanes have been shown that they can turn east at any time.
Barbour says tropical storm winds could come into the Gulf Coast starting late tomorrow (Sunday) night or early Monday morning.
Earlier today, President Bush declared an emergency exists in Mississippi and ordered federal aid to supplement state and local efforts for Hurricane Gustav.
Barbour had sought the designation to get emergency services in place in advance of the storm.
Gustav is now a Category 4 storm. It is expected to strengthen tomorrow.
Bush's action authorizes the Department of Homeland Security, Federal Emergency Management Agency to coordinate all disaster relief efforts.