Keep your rain gear handy.
The record rain that hit Seattle and drenched the Olympic Mountains Thursday will keep pounding the region for most of the weekend, says KPLU weather expert Cliff Mass.
Warm temperatures are also continuing with highs expected to get near 60 degrees around western Washington.
“And the freezing level is way up there, at 7,000 or 8,000 feet,” he said, with the snow level at 6,000 feet. “So the passes are getting rain, I’m afraid,” he said.
‘A Primo Atmospheric River Event’
Seattle charted a one-day record rainfall of 1.03 inches at SeaTac on Thursday. “And the Olympic Mountains got as much as 7 or 8 inches,” Mass said.
“That’s a lot of rain — potential for flooding,” he said, though he added that the mountains also produced a “phenomenal rain shadow” in many locations to the northwest, sheltering areas north of Seattle and places like Whidbey Island and the southern San Juan Islands, sparing them from much rain. “They’ve only gotten a tenth of an inch,” he said.
The wet warmth is the result of what he describes as “a primo atmospheric river event,” in which a narrow stream of warmth and moisture coming from the subtropics hits our region. It’s also bringing a lot of rain to parched areas of Oregon and northern California.
Dry Patches Possible Sunday Morning
There’s a prospect of some dry patches in western Washington on Sunday, Mass says, but as a series of storms moves in, the timing is very difficult to predict.
The rain will pick up in some periods and back off in some other as the storms come through, he says. Saturday will be a warm, wet and possibly windy day.
“There could be a little bit of a gap Sunday morning, but only for a few hours,” Mass said.
Late in the day Sunday or early Monday, Mass says we can expect another system with the potential to bring stronger winds to western Washington.
“So we have to watch that. It’s a pretty intense low pressure system coming in,” he said adding it could produce a windstorm.
Drier Skies Likely Tuesday
Monday will likely be a transition day with some showers and the likelihood of drier skies.
“Several of the models right now suggest that Tuesday and Wednesday, a big ridge is going to develop over the west coast and it will finally start to dry out,” Mass said.
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The weekly KPLU feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KPLU Environment Reporter Bellamy Pailthorp. Cliff Mass is a University of Washington Professor of Atmospheric Sciences, a renowned Seattle weather prognosticator, and a popular weather blogger. You can also subscribe to a podcast of “Weather with Cliff Mass” shows.
