Enjoy dry weather while it lasts; atmospheric river on the way


PORTLAND, Ore. (KOIN) – We have some very nice weather over the region right now that is keeping the sky blue and the temperatures above normal. Crack the windows open when you’re inside and if you’re outside, you are likely taking in the sunshine if you’re in the valley.

However, things are set to change soon in the next day.

There is a large mass just to the west of us, which is going to be the source of our first rain event of the month come Thursday (likely later in the day), but more impactful come Friday.

It’s always a pleasure when we can see the mountains in the distance, but it doesn’t feel as crisp as it could be, right? As we get closer to our event, there is some moisture in the air. You can’t beat that view of Mt. St. Helens there in the distance as we look north out of the KOIN tower Wednesday afternoon.

Wednesday temperatures should be pushing 60, with our foot on the spring pedal for another day. Temperatures were chilly in the morning, in the lower 30s, and we shouldn’t be back to that tonight. More clouds around and overnight lows probably into the lower 40s. I’m glad we talked about planting in yesterday’s weather blog. We still aren’t in the clear for freezing temperatures at this time, especially outside of Portland.

Now, we have started the month with three fabulous dry days. We have something else to get back to and that is the rain.


In true winter fashion, we have another atmospheric river that is approaching the Pacific Northwest (PNW) right before the weekend. The next few days the clouds will continue to increase from west to east, but it will be the most notable for the Oregon coast. The view from Seaside today, looking to the west, is clouds. Our next system is inching closer and it will have a larger impact for the coast by Thursday and most definitely Friday.

This is an idea of that ribbon of moisture and that stronger southwest wind come Thursday night. Do you see that swoop of green that is moving towards the United States? That is going to be that atmospheric river carrying over some moisture. We get an extra boost on Friday as more energy kicks through the western side of Oregon, impacting more folks at that point of time.

Did you catch Meteorologist Kelley Bayern’s tweet this morning? This is going to be classified as a low-end atmospheric river, but it will be enough to bring in some heavy rain and that is going to spread into the valley Friday bringing in our wettest day this month (not saying much since it hasn’t rained).

Once a front finds a way east and we get that surge of atmospheric moisture, totals will come with it. These rain totals are not set in stone but you get the picture as it will be a three-tiered event. Larger totals for the Oregon and Washington coast, with slightly lower totals through the valley up to Seattle, then much lower rain totals from the Cascades to the east. Weather models are projecting a large jump from Friday morning to Friday afternoon. That is going to be the window where we will find our most rain. It’s not going to be a day that you’ll want to be outside around here. Rain totals shooting to about an inch by Friday night. Notice the larger accumulations over in Tillamook and areas south near Newport. Rain jackets will be needed. This will be our first real soaking of March.

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