Friday, August 2nd 2019, 9:00 am - Heavy rain gets a helping hand from thunderstorms on Friday.
Hours of moderate to heavy rain marked the first day of August for parts of Vancouver Island, and much of the rest of southwestern B.C. is still in line to see an unusually rainy start to the month, courtesy of an unusual visitor -- at least, unusual for this time of year. A total of 100 mm of rain or more could fall over parts of Vancouver Island and the South Coast to close out the week, along with a thunderstorm threat that means some spots will see more than their average August rainfall in just the first few days of the month.
ATMOSPHERIC RIVER MAKES FOR SOGGY START TO AUGUST
The 'atmospheric river' is no stranger to the B.C. coast, but it doesn't make many visits during the summer. This moisture flow is part of what gives the Pacific Northwest and the B.C. coast its rainy reputation as it transfers water vapour from the tropics to the poles. The B.C. coast sees about 25 atmospheric river events every year, but mainly during the fall and winter. While they're always on the move over the Pacific, atmospheric rivers only intersect the B.C. coast once every 5 to 10 years at this time of year.
The unseasonably wet weather prompted Environment Canada to issue rainfall warnings and special weather statements for much of Vancouver Island, Metro Vancouver, and the Sunshine Coast. These alerts continued Thursday evening before being dropped through early Friday morning.
YOUR ENTIRE AUGUST RAINFALL, IN 24 HOURS
Coming now, at what is typically the driest time of the year, the expected rainfall will likely out-do monthly averages for many locations. Tofino, for instance, can expect to see its entire August-average rainfall in the first two days of the month. Comox is in line for the same treatment. In fact, Comox stands to see more rain in one day than it has in the past three Augusts, combined.
While Metro Vancouver will be on the outskirts of the heaviest rain the city -- particularly the north -- can still expect a healthy helping of rain. It's not out of the question that North Van will see close to its August monthly average, too.
Unlike the rainy season, however, this tropical blast won't be around for long. Rain will start to taper off through Friday morning, though an unstable atmosphere does boost the thunderstorm risk across much of the region through Friday. Much more seasonably-dry early August conditions move in for the weekend.