Prepare for gridlock this coming weekend, Tacoma.

The Washington Department of Transportation announced Monday that contractor crews intend to reduce southbound Interstate 5 to two lanes between Portland Avenue and South M Street from 10 p.m. Friday, Aug. 26, to 5 a.m. Monday, Aug. 29.

Coupled with previously announced lane restrictions for paving on the Tacoma Narrows bridges over roughly the same time, traffic through the City of Destiny is setting up to be a nightmare.

“We recognize the around-the-clock restriction will be a big inconvenience for area drivers, and we strongly encourage people to avoid the area altogether,” said Brenden Clarke, a DOT project engineer.

The I-5 work is necessary to replace about 1,200 feet of concrete which dates to the 1960s, DOT officials said. It is part of two over-arching projects to replace the freeway’s surface and expand it’s width for the ultimate construction of HOV lanes through Tacoma.

“We are working in a very tight location that gives us no choice but to squeeze traffic down to two lanes to complete this work,” Clarke said.

Nearly 100,000 cars per day travel that stretch of I-5, and DOT traffic experts predict long southbound back-ups even if up to 50 percent of those drivers stay away.

The department reported that drivers who do slog through the traffic jam might see lanes closed but “no active work in progress” during the latter half of the weekend. The new concrete will be curing during that time and can’t be driven on, the department said.

Also this weekend, crews will reduce traffic to two lanes in each direction on state Route 16 across the Narrows and divert westbound traffic onto the eastbound bridge to complete a repaving project there. That work will begin about 6 p.m. Friday and last until 5 a.m. Monday with similar restrictions scheduled for Sept. 9-12.