The deep upper-level low-pressure weather system over the Gulf of Alaska will begin to swing toward the Pacific Northwest today with increasing cloudiness expected throughout the day. A moisture laden cold front will also move on to the Washington Coast and toward the Cascades by late in the afternoon spreading light showers. Southerly winds will increase ahead of the incoming weather system with the strongest speeds setting up through the Okanogan Valley, Waterville Plateau, and portions of the Western Columbia Basin. By tonight, we could see winds from 10-20 mph and gusts to 25 mph. Big changes will then arrive as the Gulf low moves into the Pacific Northwest. Almost all of Northcentral Washington locations will stand a decent shot of wetting rains tonight and into the early morning hours of Saturday. Rainfall amounts between a quarter and half an inch with locally higher amounts are expected. We have an 80% chance for showers and maybe even a thunderstorm tonight and early Saturday morning.
As the slow moving weather system moves east on Saturday and Sunday we will continue to see windy conditions of 10-20 mph and much cooler temperatures with highs only in the mid to upper 60’s. Rainfall and cooler temperatures are no surprise for Northwest in June however, given the warm and dry weather of late, those participating in outdoor adventures should be prepared for a sharp change in weather conditions, particularly those with interest in mountain recreation.
On Monday and through the middle of next week, high pressure will build into the region ahead of the next incoming weather system on Thursday. This will bring a couple of days of dry weather with temperatures warming up into the 70s and lower 80s.