Lower Mainland sees a rainier-than-usual spring. Here's why

Thursday, April 20, 2017, 1:27 PM - The long weekend brought the return of what's become a rare visitor for the Lower Mainland — the sun. Despite a welcome break in the clouds, a showery weather pattern continues this week in what's already been an unusually rainy spring for the South Coast.

Snow accumulations and rainfall totals are still climbing at a time of year we'd expect the Lower Mainland to be starting to dry out, and while temperature trends are on the rise, Vancouver International Airport has yet to hit 15 C this year. And, unfortunately for those weary of grey skies, this week offers little relief.

While showers continue Thursday morning for the South Coast, they are expected to ease into the afternoon, with rain and snow continuing for B.C.'s Interior.

There is also the risk of thunderstorms for northern portions of Vancouver Island, and a swath of the Interior Thursday.

The province will see a break from the wet weather on Friday, courtesy of high pressure. However, this will be short-lived as another push of moisture will bring showers over the weekend.

"After a mild and dry start to the weekend, showers return to the South Coast of B.C. Saturday afternoon/evening," says The Weather Network's Dr. Doug Gillham. "It's a milder system, with snow levels near 2000 m, dropping to near 1500 m, then rising again Sunday. A few showers are likely Sunday, but not a washout. Next system comes Monday, with the potential for a stronger system late Tuesday into Wednesday."

The February to April average for Vancouver rainfall rings in at 307 mm - a number that's already been surpassed in the last 60 days.

After March set a record for the "gloomiest" weather since 1972, with a total of only 70.5 hours of sunshine, along with toppling a rainfall record from 1956, residents may have been hoping for a little less in the way of 'April showers'.

It's typical in La Niña winters to see higher-than-average precipitation for southern British Columbia, though the long, harsh winter of 2016-2017 exceeded most expectations for the weak event in the Pacific. While the oscillation is well on its way to transitioning to the El Niño state, there is a lag as the teleconnections associated with it disperse around the globe. And, at least for now, that means an active storm track with its sights set on the South Coast.

Spring skiers have, on the other hand, have been in luck as resorts are still welcoming fresh alpine snow. Whistler Blackcomb is expecting up to another 35 cm by Wednesday this week atop a base that still measures more than 3 metres.

Grouse Mountain announced they've decided to stay open until at least April 30th for spring skiing given the forecast and conditions.

This year's exceptional alpine snow pack is also a boon for the region's reservoirs. Speaking to CKNW earlier this month, North Vancouver Mayor Darrell Mussatto reported reservoir levels were at maximum capacity. "[It] puts us in a much better situation in the spring and going into the summer than we were in the past," Mussatto said.

So how's the outlook for those May flowers and beyond?

In our summer forecast sneak peak, Dr. Doug Gillham points to the developing El Nino as "one of the final keys" that will determine how the summer pans out for Canadians. "Some years there are strong signals in the global pattern that allow for higher confidence in a seasonal forecast, but unfortunately this is not one of those years," Gillham writes, but adds that there are signs that British Columbia may be trending warmer and drier than last summer, meaning those full reservoirs could be even more important than usual.

Sources: CBC News | CKNW | NOAA |