PORTLAND, Ore. (KOIN) – Cold rain moving our way as an active November continues Tuesday. The morning should start dry, so if you’re reading this before lunch, you don’t have to worry about the rain just yet.
Showers increase in the afternoon and then the moderate rain follows as a cold front moves through in the evening. If you planned on being out most of the day for a hike, you’ll want to be prepared for a wet drive home.
As we take a look at the upper-level wind, we have an area of low pressure navigating the Gulf of Alaska, associated with a trough. This is the system that will impact our region on Tuesday. The wind aloft is fairly strong, which will support a stronger system for us to work with. What does that mean? Likely more mountain snow and a better chance for rain in the valley.
We look at this system before sunset on Monday to gauge how the weather models are lining up and what we have coming our direction. We are on track for that front to arrive on Tuesday evening around sunset.
This is going to bring in a nice sample of moisture for the Pacific Northwest (PNW). A weak ribbon of moisture is situated in our region. This isn’t a significant atmospheric river that can bring in heavy sustained rains, but enough moisture for measurable rain in the valley and a healthy dose of mountain snow overnight.
Right now the scaffolding is just about in place to support this system on Tuesday. I would say we are likely going to get around .25″ of rain in the valley with enough mountain snow to make the ski resorts happy.
Weather models have been consistent on the timing Tuesday with showers starting as early as 4 PM. At this time, snow levels are going to be above the passes. Weather models have the rain picking up around 7 PM or so with that moisture yet to really impact the Cascades in Oregon. That will follow later at night, after midnight.
At that point, the rain will settle down in the valley and will become more scattered. Snow will be coming down for the mountain at this time, adding to the base of the ski resorts. Snow levels dropping to around 3500 feet by Wednesday morning to mid-day.
As far as temperatures go? We are going to be slightly warmer on Tuesday before that cold air arrives. Temperatures likely topping off in the mid 50s with a cool down on Wednesday as a cold pool moves in. Don’t expect any massive temperature swings in the next 5 to 7 days. We have mountain snow coming but we aren’t quite cold enough to support anything lower.