We May Finally Break The Heat Wave

GFS 10-day

We’ve had a stretch of heat over the Pacific Northwest the likes of which I can scarcely remember from growing up in the area and which I’ve certainly not seen in the 4 years I’ve lived in southern Oregon. Temperatures reached 110F at times at my house over the last couple of weeks, and many records have been broken. In fact, one site in Washington State may have broken the all-time state record.

But it looks like we may finally get a break in the heat wave over the next week or so. A monster ridge of high pressure has been the culprit in the heat wave, but some long range models show the ridge retrograding offshore and allowing a trough to drop in over the PacNW. Here is the GFS 500 mb ensemble mean and spread for 10 days from now:

GFS 10-day

GFS Ensemble Mean (lines) and spread (fill), Valid 09July2015

The spread is actually pretty low for that far out, and thus troughing seems like a good bet over the west coast. This probably wouldn’t mean cool weather, but at least the oppressive heat we’ve seen should be gone.

The fly in the ointment, however, is the European Forecast. I don’t have access to its ensembles right now, but its deterministic forecast shows a brief troughy interlude followed by the ridge rebounding over the area.

Of course, we’ll have to wait and see, but at least there is some hope for those of us who don’t like living in ovens.

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Potential Wind Storm In PacNW

We’ve been through a lot of boring weather through early winter, but we’re finally getting some storms again.

 

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McMinnville, OR Tornado Rated EF1

Following up on the post I made yesterday about the tornado touchdown in McMinnville, OR, the NWS survey team rated it as an EF1. This means the damage was indicative of winds of 86-90 mph.

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.

Tor pic

Tornado near McMinnville, OR on 13Jun2013. Photo taken by Bonnie Helpenstell and grabbed from NWS Portland Facebook page.

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.

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Tornado In McMinnville, OR

Funnel cloud from Harrisburg, OR today (13Jun2013)

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:

Funnel cloud from Harrisburg, OR today (13Jun2013)

Funnel cloud from Harrisburg, OR today (13Jun2013)

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:

KRTX 0.5 degree reflectivity

KRTX 0.5 degree reflectivity valid 13Jun2013/2333Z

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.

KRTX-0.5Z-V13JUN13-2333Z

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:

2013061400.72694.skewt

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.

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Tropical Storm Andrea Is Born

We are about to get our first named tropical storm of the season this afternoon. Hurricane hunter aircraft reportedly found a well-defined circulation with the cloud shield seen southwest of Tampa on the following satellite photo. She will be called Andrea. June seems a little early for this! :)

Visible

Visible satellite image of tropical system currently forming in the Gulf of  Mexico, valid 05Jun2013/2115Z. It will be called Andrea.

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Photos Of Wildfire In Grants Pass, OR today

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.

20130531_170635

 

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. 😉

20130531_165007-c

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More Tornado Terror For OKC Area

Three hooks on radar within 50 miles of Oklahoma City, OK this evening.

Radar

0.5 degree reflectivity from OKC radar – valid 31May2013/725pm CDT. Yellow arrows point to hook echoes.

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Interactive Before/After Map of Tornado Damage In Moore, OK

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.

Snapshot of application - click to go to the app

Snapshot of the app – click to go to the app itself

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Debris Ball Signature On Radar – Moore, OK Tornado

When I saw this radar signature, I knew it was bad. I had no idea though. Absolutely awful.

Radar

Radar

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Photo Of Destruction From Texas Tornadoes

Big tornadoes rolled through north Texas yesterday. I read some were two miles wide. This photo from CBS news is pretty striking.

before-and-after-TXtors

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