An abundance of crisp blue skies have ushered in a relatively dry start to fall this year in the Pacific Northwest, providing a stunning backdrop as the leaves begin to turn. Some sunnier afternoons allowed folks to keep wearing their shorts and sandals. But KNKX weather expert Cliff Mass says there are some sure signs of autumn.
“One thing we’ve noticed is that the morning temperature has really declined,” Mass said. He notes that the mercury has been dropping into the mid-40s in Seattle and even into the 30s in more rural areas, like Shelton.
“This week a few people even had frost here in western Washington. And go to the other side of the Cascades and a lot of places are getting below freezing,” Mass said. “So we’ve definitely had a transition.”
This weekend will be a mixed bag with showers off and on and rain in some places.
Friday will be “a really nice day,” Mass said. “Plenty of sun, a little bit of high cloudiness, temperatures getting back up into the 60s.”
Late Friday and into Saturday, he says a Pacific front will move in, bringing showers with it, especially on Saturday. But Mass says you can escape the wet weather if you know where to go.
“The winds aloft are pretty westerly, which means that Seattle and probably down to Tacoma is going to be rain-shadowed in the lee of the Olympic Mountains. So, I think we’re only going to get a little bit of light rain most of the day tomorrow,” Mass said.
On the other hand, he says the mountains are going to get hit hard. So you probably don’t want to plan a hike for Saturday.
“There could be a few inches (of rain) in some locations on the western slopes of the Cascades,” Mass said. But if you want to escape rain altogether, just cross the Cascades, he says.
“There’ll be a really good rain shadow as you get down into Ellensburg and Wenatchee and Yakima, down on the other side.”
Later Saturday, Mass says a Puget Sound Convergence Zone could develop somewhere between Seattle and Everett, bringing heavier precipitation to that area.
On Sunday, the pendulum will start swinging back to sunny fall weather, Mass says, with light showers in some places in the morning that clear out later in the day.
“So it will end up being partly cloudy during the afternoon and temperatures only getting up to around 60-61. So, cool, but once you get into the afternoon I think it’ll be pretty nice on Sunday.”
After that, he says it looks like a ridge of high pressure starts developing Monday and Tuesday, which should bring sunnier skies again before the showers return later in the week.
“So, we’ve definitely transitioned in temperature, but we’re still way below normal in precipitation for the month,” Mass said.