Weather Blog

Sunshine to hail to... funnel cloud?

Sunshine to hail to... funnel cloud?

Whoever penned the phrase, "Don't like the weather? Just wait 20 minutes" was probably experiencing a day just like today in Seattle, where we've gone from blazing sunshine to raging hail storm with even a little lightning and perhaps a brief funnel cloud.

Here is a time lapse video of the entire day Monday through 3 p.m., taken from atop the University of Washington Atmospheric Sciences Building. You can see how our cold, unstable air mass had the clouds bubbling through the day, followed by what we called the "Cone of Sunshine" where it was mostly clear over the city, but raining just to the north and south of the city limits. (See satellite image of that here.)

Finally, a big cell moved through bringing hail and lightning:

But right at the end of the video, we noticed something that sure looks like a funnel cloud.

Here is a still shot of what it looked like:

And here is the video again -- just the last 30 minutes. The funnel comes right at the end and it's quick -- at 2:55 on the time stamp and the video ends at 3:00. I think it's a funnel cloud because you can see the rotation in the clouds and that distinguishes it against what we call "scud" which is just low hanging cloud gunk that frequently gets mistaken for funnel clouds.

This is likely a "cold core" funnel cloud. They're like a tornado's little brother in that they look like tornado/funnel clouds, but aren't nearly as destructive. These are spawned from non-severe storms and can occur when you get a tightly wrapped rush of rising air that can appear as a funnel.

Cold-core funnels rarely reach the ground, and if they do, are very weak and rarely cause any destruction.

They are actually, well, I don't want to say "common" but they aren't that rare either around here, especially on days like today when you have cold, unstable air around, and Convergence Zones are typical culprits.

Speaking of cold, unstable air, hail was also on the docket for today. Here is some video taken from a KOMO employee in South Seattle:

And here is video from KOMO Photographer Eric Jensen that shows a Seattle press conference deluged by the big storm, and other hail video from the city:

We'll see these random showers through the end of the day, then we'll clear out for the rest of the week.

How can you tell it's a funnel cloud?

If I had seen that photo at the top by itself, I would be skeptical that it was indeed a funnel cloud -- it's the animation that's the key in that it shows some rotation.

Many times, low hanging "ragged" clouds are mistaken for funnel clouds because at first glance it can appear as one. But the way to know for sure is to watch for rotation.

About two hours after the funnel cloud was noticed, some more ominous clouds moved over Seattle. But these were harmless.  I took a video with my cell phone camera off our balcony to illustrate how they might look like funnel clouds, but aren't: