The Willamette Valley was treated to not just one, but two consecutive nights of thunderstorms this past weekend.
A fairly rare pattern developed to where thunderstorms bloomed off the Washington Cascades but the upper air flow brought the storms south into northern Oregon. (Typically, thunderstorms tend to move in from the south or east around here.)
The unusual air flow was caused by low pressure to our southeast, wrapping upper level winds back around from the north/northeast. The air was also a bit unstable, and all we needed were the Cascade Mountains to provide lift and, voila!, thunderstorms.
It was even more rare to have the pattern repeat itself for a second day and have isolated storms just happen to find their way into Portland once again. It was as if Portland was the head pin on Mother Nature's bowling alley this weekend.
The storm brought some torrential downpours in addition to the vivid (and loud!) thunder and lightning. According to University of Washington research meteorologist Mark Albright, a spotter in Vancouver just west of I-5 reported a whopping 0.40" of rain... in 5 minutes!
The show made for some dramatic photographs. Aside from the lightning, there were dazzling displays of mammatus clouds -- those bumpy, circular clouds. They're a signal of very unstable air and usually accompany strong storms. The photo at the top perfectly captured both the mammatus clouds and lightning. (Great shot!)
Here are a couple other videos from the storm, including one that shows a lightning strike in slow motion that hit near Portland's Airport:
Here's to a much calmer week around here!