We’ve been through a lot of boring weather through early winter, but we’re finally getting some storms again.
I have seen some video of the tornado (here and here) but they aren’t great. In fact, I can’t really see much at all. But the following photo was posted on the NWS Portland Facebook page, and it shows the tornado pretty well.
By the way, this tornado was entirely different than the big ones out in the central and eastern U.S. This kind is called a cold air funnel and is formed by processes different than the big ones that come from supercells. A violently rotating column of air reaching from a convective cloud to the ground is a tornado no matter what the mechanism. But they’re different. It will be easier to explain in a video, so I’ll do that some time.
An NWS storm survey team confirmed that a tornado touched down in McMinnville, OR this afternoon. They have yet to say what rating the tornado was on the F-scale, but there was significant damage to some buildings.
I have heard there is video of the whole thing, but I’ve yet to see it. I will post a link when it comes out. However, I did find this photo of a funnel cloud from Harrisburg, OR this afternoon:
Tornado confirmed and a cool photo of a funnel cloud…in western Oregon no less! Check.
Of course, that’s not enough for me. I like to investigate why these things happen (not surprising, I suppose, since it is my job to forecast these things). Here are the radar images from around the time of the reported tornado in McMinnville:
The cell that caused the twister is fairly obvious. It had a ~60dbz core which is pretty good, but at this distance from the radar, we are sampling at ~3,700 feet above ground level. In other words: we’re not seeing much, if any, of the portion of the cell that contained the tornado.
The cell also had a **very** weak rotation at that level. Green indicates movement toward the radar (which is located in Portland – toward the upper right) and red is away. The values in there are pretty lame, like 10 knots in each direction, but that rotation is cyclonic. Again, though, we’re overshooting most of it at this range.
Finally, here is the sounding from Salem, OR. It is quite close by and, as luck would have it, taken at right around the same time:
There is some **weak** cyclonic rotation on this sounding as well – notice how the wind barbs show southerly wind at the surface and then it gradually turns toward the west/northwest with height (called veering). It’s also pretty moist in the low levels and there is some very marginal instability.
None of this information screams tornado, and I never would have forecast it to occur based solely on what I’ve seen so far. But it’s not hard to see how it happened in hindsight.
This is yet another learning experience and a pretty unusual and neat occurrence to boot.
Wildfire rolled up the hills just east of Grants Pass, OR this afternoon. My understanding is that it’s called the Beacon Hill Fire and was started by a truck throwing sparks as it move along I-5. It was close enough to my home that I was able to check it out for myself. I took the following photos from Grants Pass this afternoon.
There was isolated extreme fire behavior, including pockets of torching. Luckily it wasn’t windier today. I wasn’t able to photograph the worst of it, but the I did get the one below. It’s not terribly dramatic, but those flames are half as tall as the nearby telephone pole. You can also see how close this was to Interstate-5. I would have loved to get in closer to see what was going on, but then I’d just be part of the problem.
This interactive map has a slider bar that you can use to scroll back and forth between the before and after damage photos. You can also zoom in and out. This really puts the unbelievable damage caused by the tornado into perspective.
Big tornadoes rolled through north Texas yesterday. I read some were two miles wide. This photo from CBS news is pretty striking.
Winter may have one parting shot for us in the PacNW next week. The models are showing a big, deep, cold low over the PacNW around the middle of next week.
Here are a few forecast graphics from the American GFS model that show the ugly truth quite well:
Big trough right over us. Period.
And cold! Those blue lines are not great news since they show where the really cold air is. A 528 decameter thickness is cold any time, but for May? Sheesh! For reference, we’d be thinking about snow at sea-level with thicknesses of just 60 meters lower (522 dm). If this is exactly right, snow levels will be quite low – pass level at least, maybe lower.
If you’ve been following this blog for long, you know I wouldn’t post this if it was some wild, one-off solution. All the models show this and have been showing something like this for several days. Model spread is also very low for being this far out and this anomalous. In other words, it’s probably going to happen.
It’s always good to remember that this too will pass.