‘Mainly mountain’ thunderstorms could move west Friday into the weekend
Aug 19, 2026, 12:14 PM
Rain pools and collects along some Seattle city streets. (Photo courtesy of KIRO 7)
(Photo courtesy of KIRO 7)
Enjoy the late-summer sunshine this week, as thunderstorms could strike western Washington starting Friday into the weekend.
“While an eruption of thunderstorms is by no means a certainty just yet, there is the potential for at least some mainly-mountain thunderstorm activity,” KIRO 7 meteorologist Nick Allard stated.
The predicted storms are expected to develop late Friday afternoon, with a chance of becoming more widespread that evening and overnight into Saturday. Meteorologists have described the thunderstorms as “mainly mountain,” but they could move west of the Cascades Friday night.
“An eruption of thunderstorms is far from certain, but we’ll be watching the potential closely because lightning could spark new wildfires,” Allard added.
The biggest fear with the upcoming thunderstorms is the lack of expected moisture with the increased risk of lightning. Lightning occurring without significant rainfall could quickly ignite new fires. As of mid-August, as many as 780,000 acres have burned across the state this year — the third-highest acreage burned on record for the state in the last two decades.
As of this reporting, weather models cannot pinpoint exactly where the thunderstorms will form, but they are expected to occur primarily along the Cascade Mountains in central and eastern Washington with a chance of moving west. In the mountains, heavy rain and hail are expected briefly during the thunderstorms.
Showers and thunderstorms could continue into Sunday for regions east of the Cascades.
“If the trough of low pressure moves across the region, it would also bring more clouds and cooler temperatures with highs in the 60s to low 70s to start next weekend,” Allard said.
As summer wanes, western Washington has most likely experienced its hottest weather for the year. The Puget Sound region is expected to reach 80 degrees a couple of times in September, with the rest of the month hovering around the 70s.
This is a developing story, check back for updates
Contributing: KIRO 7
