PORTLAND, Ore. (KOIN) – When it is time to start planning your next hike or local winery to check out for the weekend, you probably want to be aware of the chance for a few isolated thunderstorms, right?
We may have some stormy moments come Saturday with cold air rolling in with a trough that will lead to some instability in our atmosphere. A positive-tilt to this trough, where the deepest area of low pressure is to the northeast, doesn’t tend to lead to severe weather but for us in the Pacific Northwest, that cooler air may be enough for some small hail to mix into our shower activity.
The futurecast, which is using model data from the ECMWF (European Centre for Medium-Range Weather Forecasts), is rumbling a system through on Friday night with additional energy Saturday. Leading to some showery conditions from the coast to the Cascades. Snow levels will be dropping in this pool of cooler air for the mountains and even to about 1,000 feet on Sunday morning.
When we are anticipating thunderstorms, we use a product called CAPE or convective available potential energy, which you can think of as fuel for thunderstorm development. There is a modest amount available come Saturday afternoon with the likelihood of some sun breaks bringing some heat to the table. With that pool of cold air aloft, that will keep the freezing level low as well and with some action aloft, the ability for some hail to form is possible.
If you’re interested in how hail forms, you can watch the video or check out the graphic in the slideshow. To bring this back around, if you’re thinking of being outside come Saturday afternoon, that will also be the timeframe where we may see that hail embedded into our small isolated cells that develop come Saturday afternoon. Safe hiking!