Rainfall warning issued for Lower Mainland beginning Friday night

A map shows the weather advisories in effect in B.C. on Friday, Aug. 23. (Environment and Climate Change Canada)

More heavy rain is on the way to the Lower Mainland this weekend, according to the federal weather agency.

Environment and Climate Change Canada issued a rainfall warning covering Metro Vancouver, the Fraser Valley and Howe Sound Friday, saying around 50 millimetres could fall by the end of the weather system.

“A low pressure system off the Oregon Coast will move inland today and track across southern B.C. tonight,” the weather notice reads.

While rain was already falling in some areas early Friday afternoon, ECCC predicts the heavy precipitation to begin Friday evening before tapering off into showers on Saturday.

“Heavy downpours can cause flash floods and water pooling on roads. Localized flooding in low-lying areas is possible,” ECCC wrote. “Watch for possible washouts near rivers, creeks and culverts.”

Farther inland, the weather agency predicts 20 to 30 millimetres of rain, or up to 40 millimetres in the hardest-hit areas, according to a special weather statement in effect for the Fraser Canyon, eastern Fraser Valley, South Thompson, Whistler and Pemberton.

Meanwhile, B.C.’s Southern Interior is under a severe thunderstorm watch Friday, which means conditions are favourable for the development of storms that could produce large hail, heavy rain or strong winds.

Recent rain and cooler temperatures in southern B.C. have been welcome on the wildfire front, with the BC Wildfire Service saying in its daily situation report that the weather has helped a number of larger fires to be classified as under control or being held.