PORTLAND, Ore. (KOIN) – We may have sounded like a broken record the last few days, you know, praising the dry and somewhat sunny days. It’s because we are back at the winter weather this weekend and that will pair with an atmospheric river (AR).
The incoming system should supply us with water for some soaking rain and mountain snow by Saturday. One way to visualize that plume of moisture is by using what we call precipitable water vapor, which is a gauge of how deep the moisture may be and it’s also a way to analyze the transport of that water vapor. Notice the ribbon of blue approaching the Pacific Northwest in the weather graphics below. That is representing a moderate stream coming from the tropics all the way down from Hawaii.
That stream should connect with Washington and Oregon as early as Saturday morning, which will slowly shift south leaving multiple hours of rain for many. That moisture will ride the top edge of the area of high pressure that will be building over the Pacific west of California. That placement is specific to the direction of that stream hitting Oregon.
How much rain are we talking about it? Precipitation totals will continue to be the most aggressive for the Oregon coast and areas of the Cascades. How about close to home? The Willamette Valley will likely see somewhere around .50 – 1.00 inches of rain, with lower amounts further south near Eugene and totals a little higher closer to Vancouver.
If you’re interested in more information about atmospheric rivers, you can learn more about them in the video below.
Follow KOIN 6 for the latest news and weather