Thunderstorms for some Saturday, cooler Father's Day for Portland area

PORTLAND, Ore. (KOIN) -- The threat of thunderstorms, heavy rain and cooler temperatures returns in Portland's late spring storm threat.

Saturday will likely be the rainiest day of the weekend and the coolest. Mostly cloudy skies will drop temperatures to the mid-60s during the afternoon. Isolated thunderstorms are likely for much of Washington, but northwest Oregon could see a few stray storms as well. No severe weather is expected, but small hail and lightning are the biggest threats to outdoor activities this weekend.