LAKE CITY, Fla. -- Tired but committed firefighters gained ground on the largest wildfire in Florida history over the last two days, taking advantage of the calm weather to improve containment to 65 percent.

But lightning, followed by higher winds and lower humidity in the forecast for Thursday and Friday could cause the fire to jump containment lines and put more homes in danger.

"We do expect some spotting over the lines today as winds increase," U.S. Forest Service incident commander Jim Caldwell said Thursday morning. "Five Points, Deep Creek, Moccasin Circle, Taylor, Benton, Lake City and Watertown are still at risk."

Caldwell said Thursday's winds should send flames to 8 feet in any direction and allow the fire to advance up to three-fourths mph.

At last report, the fire had burned within two miles of U.S. Highway 441. If it jumped U.S. 441, that would trigger the evacuation of an additional 1,500 homes -- including residents from Hamilton County for the first time.

More than 400 firefighters, assisted by dozens of bulldozers and six helicopters were in position to battle areas where they anticipate the fire to jump fire breaks.

Officials said residents evacuated from more than 700 homes in northern Columbia County since last week can return to get supplies and tend to emergencies, but they are still not allowed to stay in their homes.

"These are our neighbors and friends," Columbia County spokesman Harvey Campbell said. "We hoped we had something to announce today, but we still have enough concern about the weather today and tomorrow that we're not comfortable of saying 'go back' and feel like it's the right thing to do for them in terms of safety."

Higher winds also present a danger blowing burning snags onto firefighters.

An additional 1,000 acres burned overnight, bringing the Florida total to 120,515 acres in Florida, with 140,821 acres burned north of the Georgia border.

Officials are hoping the front brings not just lightning, but rain.

Caldwell said that the fire event will continue in some form until the area gets substantial rainfall -- possibly from tropical weather events in mid- to late summer.

Thursday's front brings a wind shift that has dense smoke from the massive fire coming back into northeast Florida and southeast Georgia. Visibility has dropped through the day over Jacksonville, and reported down to one-quarter mile over Camden and Glynn counties.

"Later on tonight, the winds will make a change to the northeast, pushing it away from coast and toward Palatka, heading back into, unfortunately, areas like Lake City," Channel 4 meteorologist Richard Nunn said Thursday on the local station at noon.

Lt. Governor Visits Firefighters, Residents

After getting a firsthand look at the fire damage from the Bugaboo Scrub Fire, Florida's Lt. Gov. Jeff Kottkamp spoke with the residents of Columbia County, calling the 180-square-mile blaze that burned out of the Okefenokee Swamp last week the largest in Florida history.

"One of the purposes for me to be here along with other representatives is to make sure that we have provided every single resource we can," Kottkamp said at Wednesday's briefing.

Firefighters have been able keep the blaze away from widely scattered rural homes -- the nearest it has gotten to the highway is about one mile.

While the smoke had lifted enough to open interstates 10 and 75 to traffic, drivers were warned periodic closures were possible. U.S. 441 remained closed from I-10 north to Homerville, Ga.

Lake City has declared a water shortage, asking homes and businesses not to irrigate and to suspend nonessential uses of water to ensure there is enough water for firefighting efforts.

The Red Cross shelter at Columbia County High School remained open Wednesday.

Ashsah Dees, 34, and her 9-year-old daughter, Meagan, were among those evacuated.

"I live in the middle of the Osceola National Forest. It could come at my house from any direction," she said. "You bet I'm worried."

Dees said she was able to go home for a few minutes and saw a tanker truck sitting in her front yard, which made her feel better.

"We're just throwing everything that we have at it," said Forestry's Russell Hubright said on Wednesday. "We've got air tankers flying, we've got helicopters flying, we've got dozers plowing, we've got hand crews working. We're doing everything we can, all the strategies we can to tame this beast."

The flames jumped containment lines three times on Monday as brisk winds, low humidity and high temperatures made work difficult for an army of local, state and federal firefighters. But on each occasion, firefighters were able to quickly extinguish the blazes.

There were no reports Wednesday of fires jumping fire lines and the fire.

Firefighters call it the Bugaboo Scrub Fire for the island in the Okefenokee Swamp where it started with a lightning strike 11 days ago.

One fire crew drove 2,200 to Florida from California to help fight the blaze.

"Firefighting is my No. 1 passion in life. It's what I want to do. There's no better way to spend my 21st birthday than being out here on the fire," said California firefighter Cory Wilford.

Sixteen-hour shifts have firefighters fighting fatigued but still valiantly battling the blaze.

"One of the guys on the line asked me this morning, 'How much more can a person take?' You just kind of wonder, but the guys just keep on going -- they have to do it. The men and women fighting this fire just have a dedication to it, and they're going to stay here until it's out," said Hubright.

"We're in here for the long haul. I have 12 more days before I get to go home," said Baker City, Ore., firefighter Jeff Trevor.

After One Month, Fires Still Threaten South Georgia

Four weeks ago, a power line falling in dry brush south of Waycross started a fire that forced hundreds from their homes, destroyed more than a dozen homes, kept Ware County schools closed for more than a week and continues to burn out of control -- mostly in the National Wildlife Refuge and surrounding stands of timber.

This blaze, called Sweat Farm-Big Turnaround Fire, has burned 138,500 acres in Ware and Northern Charlton counties since April 16. While it was called the largest fire in since record keeping began in 1957, the Bugaboo Scrub Fire is the bigger focus of firefighting. In eight days, it has spread over 250,852 acres on both sides of the state line.

The only mandatory evacuation remaining in South Georgia was changed to precautionary Monday night, meaning people in Reeves Landing and Moniac could return home but need to be prepared to leave again with 12- to 24-hour notice if conditions change.

"Everybody's being told not to let their guard down, don't unpack," said Laura Polant, a fire information officer in Fargo. "Residents are still being told to be prepared to leave, because the call can come at any time."

Deep in the Okefenokee National Wildlife Refuge a crew of fire fighters set brush ablaze Tuesday to help stem the growth of the largest wildfire in the Georgia's history.

The controlled burn -- called a "burnout" -- was along a road in the refuge about two miles from the main blaze.

"This is one of the biggest tools that we have to put the biggest fires out," said Craig Daugherty, a firefighter from New Mexico. "It robs the main fire of fuel."

Firefighters walk along the brush holding torches that drip fire. The brush is so dry that flames quickly shoot 20 to 30 feet in the air, sending hot embers and thick black smoke into the sky.

In Georgia, portions of state roads 94 and 177 remain closed, although state Road 177 south of U.S. Highway 1 has reopened. U.S. 441 is closed at the Florida border.

The Wildlife Refuge and Georgia's Steven C. Foster State Park inside it remained closed, but Okefenokee Swamp Park has reopened.

The airport in Folkston, Davis Field, remains closed.

Haze from the fires has traveled as far south as the Miami area, about 340 miles away.