An upper low spinning in the Gulf of Alaska will feed a conveyor belt of moisture into the B.C. coast mid-week along, with unseasonably cool air that will contribute to mountain pass and alpine snowfall along with heavy coastal rain and powerful winds. Power outages and ferry delays are a threat with the winds. Widespread special weather statements are in effect for the South Coast, and forecasters say, this is an unusually strong low pressure system for this time of year. More on what to expect with the impending storm and beyond, below.
MID-WEEK STORM COULD DELIVER SNOWY, RAINY, WINDY WALLOP
An unseasonably strong low-pressure system will make landfall on Vancouver Island Tuesday overnight, bringing intense southeasterly winds and heavy precipitation to much of the South Coast.
By early Wednesday morning, the low will have deepened to around 990 hPa of pressure, a typically strong fall storm. A low like this can generate wave heights of 5-7 metres off the northwestern tip of Vancouver Island.
As the cold front passes, winds will shift to intense westerlies or southwesterlies by Wednesday morning, impacting western Vancouver Island, and potentially Qualicum, Victoria, Lower Mainland and the Fraser Valley. Strong southerlies will also funnel up the Sea to Sky.
The most intense winds will spread inland later on Wednesday, peaking along western Vancouver Island during the first half of the day, with gusts exceeding 90 km/h. Georgia Strait will see lower wind speeds, generally 40-70 km/h through most of Wednesday, but gustier southwest winds near Victoria might be problematic.
The winds aloft are enhanced across southern Vancouver Island, so it is possible to see mix-down gusts approaching 90 km/h for the Gulf Islands and Greater Victoria -- this will cause power outages and probable ferry delays.
However, there is some uncertainty in the exact track of the low-pressure centre. This will impact which communities see the strongest winds. As the storm nears, and wind speeds and total precipitation amounts become more certain, warnings may be issued. For now, special weather statements span the region.
For the coast, rainfall will intensify Wednesday morning and continuing through the day, easing off in the overnight hours. Amounts will range from 20-40 mm for the Lower Mainland, and 5-10 mm for Okanagan Valley and northwestern Vancouver Island.
As well, the freezing level is also stubbornly low, meaning it will likely only be a few hundred metres above sea level at times on Wednesday across Vancouver Island. The mountain passes across the Interior will also be coated in snowfall once again, thanks to freezing levels around 1100 to 1500 metres at night.
However, during the daytime, levels will rise to 2000 metres, so mixing is likely. Snow will ramp up early Wednesday morning, likely meaning hazardous travel through the mountain passes. Snowfall amounts will be heaviest in the Sea to Sky, Coquihalla and Allison Pass regions, where 15-30+ cm of snow is possible this week.
Beyond the system, drier weather returns late week and into the start of the weekend, with unseasonably cool conditions left in its wake.
Forecasters are watching the potential for another system later Saturday or Sunday, bringing showers to the South Coast. Cooler than seasonal temperatures will dominate for the next two weeks, lingering through the end of May.
Stay tuned to The Weather Network for the latest forecast updates for B.C.