After the week of high pressure and record setting temperatures, the region is transitioning to cooler temperatures with an upper level low pressure system moving towards the coast. The system will move into Washington overnight, but we will get a cold front with it. This frontal boundary will bring isolated showers to most locations. The coastal locations and the Cascades will see the most precipitation throughout the day. We do expect measurable amounts of precipitation in the West-side valleys as well, but unfortunately it will not be enough to satisfy any deficits.
Cooler air moving in overhead will create some instability in the region on Monday. A small chance of isolated thunderstorms will occur on Monday afternoon. Areas that could potentially get these storms include the coast, Northern California, the valleys, and the Cascades. It’s not likely that the instability can surpass the mountains therefore the Basin will just get spotty rain showers Monday.
Snow levels are expected to remain high with this system. Sunday snow levels will be around 6,500′ and will decrease shortly to 5,500′ early Monday morning. If we get any winter precipitation, it will be for a brief few hours on Monday morning and will mostly be a rain/snow mixture in the upper elevations of the Cascades and Siskiyous. Surface temperatures will get above freezing pretty quickly, therefore no accumulation is expected.
Shower activity should subside by Tuesday and then a weak high pressure ridge will build back into the area for Wednesday.
Thanks for logging on and enjoy the rest of your weekend!
Meteorologist Seth Phillips