Chance of Thunderstorms, Cool, Showery conditions expected across parts of Western Oregon, Portland

. As the low moves east of the Cascades, showers will become less frequent, signaling the start of a slow pattern shift.Photo byAndrew SonUnsplash

The National Weather Service in Portland is forecasting cool and showery conditions through Saturday due to an upper-level low-pressure system moving eastward. There is a 20%-25% chance of thunderstorms through the evening, particularly across the forecast area. As the low moves east of the Cascades, showers will become less frequent, signaling the start of a slow pattern shift. By early next week, a shortwave ridge will build over the Pacific Northwest, leading to a warming and drying trend. By Wednesday and Thursday, offshore flow is expected, bringing warmer and drier conditions to the region with possible gusty easterly winds, the NWS stated.