Warm but Cloudy Forecast with Thunderstorms Likely

Aug 9, 2013

Today we’ll get plenty of sun and temps in the upper 70s to lower 80s, but clouds and precipitation are moving in for the weekend, says KPLU weather expert Cliff Mass.

“An upper-level low is approaching us from the Southwest right now,” said Mass, professor of atmospheric sciences at the University of Washington. The clouds and rain that are already in Oregon are going to move northward.

Mass says the air is moist and unstable, so it has the potential to produce thunderstorms. Computer models suggest that most of these thunderstorms will be over the Cascades and on the eastern slopes of the mountains, Mass says.

“But it is certainly possible later today and tonight that some of these thunderstorms will drift over into Western Washington, particularly southwest Washington.”

He says Saturday will be a repeat of Friday’s weather, with possible thunderstorms in the late afternoon.

“There will be a lot of lightning over the next 48 hours,” Mass said.

The thunderstorms bring with them the danger of lightning sparking new wildfires, as well as flash floods, especially east of the Cascades, Mass says.

Then on Sunday night, the threat of thunderstorms will dramatically reduce and we’ll be back to the typical mid-summer pattern on Monday and Tuesday, with morning clouds on the coast and maybe in the interior, burning off by afternoon.


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.