The Severn Bridge is closed in both directions due to strong winds.
The M48 closure is in place between J2 A466 Wye Valley Link Road and J1 A403 at Aust.
National Highways said traffic is being diverted via the M4 Prince of Wales Bridge, which remains open to all traffic.
Motorists are advised to plan their routes in advance and allow extra time to travel.
Dozens of flood alerts are in place across England and Wales and there are warnings that wind gusts could reach up to 75mph as the country is hit with stormy conditions over the coming days.
The Met Office said some of the strongest winds are likely to be along the Bristol Channel and the west coast of Wales.