Grab your umbrellas: A rainfall warning has been issued for Metro Vancouver and the Fraser Valley, with a long bout of heavy rain expected to hit Tuesday evening.

Environment Canada says the heaviest accumulation, up to 100 millimetres, will be near the mountains, by Thursday morning.

Squamish will also see up to 100 mm of rainfall by Thursday morning.

The strong Pacific front is "being fueled with energy and moisture from the subtropics," says Environment Canada.

The heavy rain is expected to taper off Thursday morning as the front moves eastward out of the area.