An isolated thunderstorm Wednesday night pushed back plans to open an extra through-lane on southbound Ga. 400.

The Georgia Department of Transportation says crews are now scheduled to begin work on the nine-mile project next Monday and Tuesday, weather permitting.

It was the second time this week that re-striping and sign placement had to be canceled, said DOT spokesman Mark McKinnon. Crews had set up barrels at the Mansell Road interchange at 9 p.m. Wednesday when the skies opened up, he said. Weather forecasters had predicted little chance of rain.

The DOT plans to convert the auxiliary lanes along southbound Ga. 400 into regular traffic lanes from McFarland Parkway in Forsyth County to Holcomb Bridge Road in Roswell. Motorists will no longer have a special lane dedicated to merging and exiting the freeway.

Next week's schedule includes converting the lanes as far north as Haynes Bridge Road. It may be after the July 4 holiday before the remaining work can be completed, McKinnon said.