An unusual recipe of conditions could produce small funnel clouds across western Oregon and Southwest Washington today, according to the National Weather Service in Portland.
The combination of an unseasonably cool low-pressure system and strong sunshine is causing an unstable air mass over the region, according to a special weather statement issued earlier today. As a result, strong updrafts within heavier showers could cause weak rotation or a weak cold core funnel cloud.
Those funnel clouds rarely touch down as tornadoes, according to the weather service. But a small tornado did cause damage in McMinnville, Ore., last week. And in March, a small tornado damaged a barn in Hockinson.
The forecast includes much of Southwest Washington, including Clark County. It also affects Oregon's Willamette Valley and the Coast Range, among other areas.