While atmospheric river has become a common term to hear in Vancouver in the late fall and through the winter, few hit the city after March.
But one is knocking on Vancouver's doorstep right now, Sunday, June 2, sent across the Pacific by a system in the Gulf of Alaska.
An unexpected visitor
"We have a somewhat uncharacteristic situation," says Philippe-Alain Bergeron, a meteorologist with Environment Canada. "It's not so typical this time of year; there's an atmospheric river."
"They're here usually in October through November to January."
He explains there are still some through February and March but they drop off through the spring. June 1 marks the beginning of meteorological summer, a very unlikely time for an atmospheric river.
The approaching wet weather has led to rainfall alerts around Vancouver, but not in the city. North Vancouver, Howe Sound, Coquitlam and the Fraser Valley are all being warned of rainfall; for North Vancouver more than 60 mm may fall.
Bergeron notes that the rain shadow from the mountains means areas further south won't get as much, but downtown Vancouver may still see more than 40 mm over then next 24 to 30 hours which is just under the threshold for a warning.
"It's bringing us a lot of moisture today and tomorrow," Bergeron says. "It's generating an abundant amount of rain."
While it's currently raining in the city, he notes the intensity will pick up around the late afternoon and overnight for the Metro Vancouver region, while areas further east will see the heaviest periods overnight and into Monday morning.
Further inland the precipitation amounts won't be as high, but it'll still help the overall drought situation, he adds.
A high of just 13 C is predicted for Vancouver Sunday, June 2. On Monday, June 3 it should be a bit warmer at 15 C.
But wait, there's more
Bergeron says things will clear up later on Monday, before a second wave from the atmospheric river arrives on Tuesday, June 4.
Meteorologists are still working out what is likely to happen then, he notes. There's a high degree of confidence Tuesday won't be as rainy, but could be much windier on the exposed coastal sections of Metro Vancouver like Tsawwassen and Point Grey.
Rainfall could be between 10 and 25 mm, depending on the Metro Vancouver neighbourhood.
A swerve into summer
After Tuesday's storm, summer should arrive.
"Once we're done with that there's a big change in pattern," says Bergeron. "It should be warm and dry for several days."
While it's still a little unclear what's on the other side of the atmospheric river, there's a high degree of confidence it'll be substantially warmer, with Wednesday and Thursday as transition days. Highs of 17 C and 21 C are currently forecast by Environment Canada.
Friday and Saturday is when the hot summer weather is more likely, with temperatures into the mid-20s, and even warmer inland. Some parts of Metro Vancouver could see temperatures of around 29 C.
Stay up-to-date with hyperlocal forecasts across 50 neighbourhoods in the Lower Mainland with V.I.A.'s Weatherhood.
