If your Memorial Day weekend plans include a hike in the mountains, be prepared for rain. And if you’re hanging around the Northwest Folklife Festival or elsewhere in the lowlands, expect showers, says KPLU weather expert Cliff Mass.
He says it’s a continuation of a pattern that started on Thursday and continued into Friday morning.
“We had a lot of low clouds moving in to the west of the Cascade Crest,” Mass said.
“There’s an on-shore pressure gradient and so there’s stratus and strato cumulous (clouds) at lower levels. But at upper levels, we’re getting flow still coming off the mountains,” he said.
Embedded in that are thunderstorms, Mass says, and even a bit of lightening.
He says Thursday in eastern Washington was extremely wet and they had lots of lightning.
“So if you were in Yakima, they had a big flood going on, there were some heavy showers in the mountains and some of those drifted over,” to the west.
His forecast for the weekend
Friday: calmer, but with showers around…mainly on the western slopes of the Cascades and near the Olympics. More thundershowers and heavy rain over the Cascades, “with towering cumulo-nimbus” clouds over the mountains, bringing showers with them. Lots of clouds in the lowlands, maybe some sunbreaks, temperatures getting up into the upper 60s. “So, definitely a knock-down,” Mass said.
Saturday, Sunday & Monday: low clouds burning off as the sun warms up surfaces and the same cloud pattern over the mountains.
“So if you’re going to go hiking over the weekend, be ready for it. If you’re going to be staying overnight, bring a tarp or something, because there could be showers in the Cascades” Mass said, of all three nights this long Memorial Day weekend.
He says he expects the potential for thunderstorms to fade back, especially for lowlands, but he warns there will still be some (potential) over the mountains.
And temperatures will still be above normal as they have been this past week, but “only up into the upper 60s –so definitely a knock-down,” 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.
