Potent atmospheric river, 80+ mm rainfall takes aim at southern B.C.

A significant stream of moisture moving toward the West Coast will fuel several back-to-back rounds of heavy precipitation heading into Monday.

This robust atmospheric river could reach scale-topping intensity as it washes over parts of the U.S. Pacific Northwest, and British Columbia will certainly feel its effects.

River flooding will be a concern with the persistent rainfall across the region.

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Moisture arrives this weekend and lingers into next week

This prolonged event will see multiple rounds of precipitation move into the B.C. coast over the next few days as a deep trough of air over the Gulf of Alaska directs heavy Pacific moisture toward the West Coast.

Moisture from southeast Asia will be the main source for this atmospheric river, although it will also merge with some moisture north of Hawaii as an added boost.

The atmospheric river moving into the West Coast on Monday will hit B.C. with AR-2 to AR-3 intensity, which means the region will see beneficial rains that could prove hazardous in spots. Folks south of the border in coastal Washington and Oregon could see significant flooding as forecasters expect the moisture supply to reach AR-4 intensity there.

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The Lower Mainland is on track for another 40-80+ mm of rain during the main event Monday through Tuesday. Eastern Vancouver Island, including Victoria, will see little rainfall, however, as the strong northwesterly flow against the island's mountains protect the area from the heavy rains.

Given the prolonged and persistent rainfall moving into the region, residents are advised to watch for pooling and ponding on area roadways. River flooding is also possible as local waterways struggle to keep up with the excess runoff. Luckily, a dry pattern over the past week will give some breathing room for the watershed.

Heavy alpine snow as freezing levels fall into next week

Freezing levels will hover around 1200 metres over the weekend, leading to heavy snowfall over the Coquitlam and Allision Passes. Drivers could see hazardous conditions as the heavy snow comes in pulses through late Sunday.

The freezing levels will briefly rise above 1800 metres on Monday evening, but will dip back to 1100 metres on Tuesday.

The North and Central Coast mountains could see 50-100 cm of snowfall through the weekend and into Tuesday. 30-50 cm of snowfall is forecast for the South Coast mountains, and 20-40 cm is forecast for the Interior's Columbia and Rocky Mountains.

Stay with The Weather Network for the latest on conditions across British Columbia.

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