Weather forecasts might make this weekend look like early beach weather, but beware of a major freeway closing between Houston and Galveston.

Southbound lanes of Interstate 45 will be closed from Scarsdale – just south of the Sam Houston Tollway – to NASA Bypass, starting at 9 p.m. on Friday, according to the Texas Department of Transportation. The closing is scheduled to last until 5 a.m. Monday.

Drivers will be detoured to the southbound frontage road and can re-enter the freeway at the NASA 1 entrance ramp, officials said.

“We will have officers present at the intersections to assist with the flow of traffic,” said TxDOT spokeswoman Deidrea George, noting motorists should avoid the area if possible.

The closing allows crews to put the finishing touches on the southbound side of the freeway, which is being widened to five lanes in each direction with a reversible HOV lane in the center.

“It is the last major traffic switch and all of the entrance and exit ramps will also be in their final configuration,” George said of the southbound work.

After Monday, southbound drivers – at least in that segment – will not face detours and shifts related to closed ramps and orange cones.

While the end of traffic switches to NASA 1, the work is hardly the end of the road for I-45. TxDOT plans to eventually widen the freeway to Galveston eventually. The next major project, set to begin later this year, is widening I-45 from six to eight lanes from NASA 1 to FM 518. The project was one of three in the Houston area chosen for funding related to a voter-approved increase in transportation spending in 2014.