Southern BC will soon be hit by unusually heavy rainfall this time of year.
And conditions before July 4 will be wet weather, with the possibility of thunderstorms Saturday night and Sunday morning.
Let me start by giving you a big look: total predicted precipitation for the next seven days. Central Europe’s cumulative rainfall forecast through 5am next Thursday (below), shows significant rainfall.. up to 2-3 inches possible in southern BC, with the North Cascades and east northern WA getting part of the wet action
The predictions of the University of Washington’s model system are similarly steamy. BC duck will be happy.
The first heavy rain will begin Saturday night as an upper-level trench approaches creating a series of thunderstorms that will move north out of Oregon.
The high-resolution UW forecast model shows simulated satellite imagery at 11 p.m. Saturday (below). The most active thunderstorms will be over the Cascades and eastern WA, but western WA will have to taste it.
Sunday will be a day of showers, and on Monday (July 4) most of the rain will be in eastern WA and far east WA.
The takeaway from the weekend’s rain is that the ground will be wetted ahead of all fireworks on July 4, reducing the likelihood of unintended wildfires and home destruction.
I should note that the cause of the weekend rain is similar to the source of our wet spring: a persistent offshore depression.
Here is a map of the upper level (pressure 500hPa, about 18,000) at 11am on Sunday. A strong bottom/bottom centered just east of Oregon.
Next Thursday? Similar features are in place. This is a cool, wet model for us. And it’s not going anywhere.
With plenty of rain in the already wet south BC, wildfires would be extinguished in that province during the summer.
This is very good news for us in Washington State. The fires in BC have been a major source of recent summer smoke.
But not this year.