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July 11-14 Severe Weather Event


Powerball

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Agree with all of this. I'm think if you strengthen the low level flow, particularly in the lowest km, you get a totally different result. With the number of discrete storms that were on the board through parts of this, that would've gotten out of hand in a New York minute.

 

There was also a big problem with moisture depth further west, as exemplified by the 00z ILX sounding. Sure you had 80s Tds near the surface, but the layer was very shallow.

 

 

Moisture depth was indeed fairly shallow at ILX.  Maybe it was a factor but I think I'd lean more toward the meager shear/inflow in the lowest km.  BTW, another reason why it would be nice to have a RAOB site in Indiana, to see if this shallow moisture problem existed farther east.

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IND did confirm an EF0 with that cell that OHweather was following.

It was very weak and in a very sparsely populated area...it looks like the tornado they confirmed occurred a bit farther SE and about 15 minutes after I saw a brief touchdown just north of Pine Village. I'm glad someone else saw it and they confirmed it...was worried because really it only briefly touched down in a few corn fields.
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It was very weak and in a very sparsely populated area...it looks like the tornado they confirmed occurred a bit farther SE and about 15 minutes after I saw a brief touchdown just north of Pine Village. I'm glad someone else saw it and they confirmed it...was worried because really it only briefly touched down in a few corn fields.

 

 

Yeah, I'm really familiar with that area as I would sometimes take 26 west out of LAF...I think Warren county is the least populated county in the state.  Did you contact IND about what you saw?

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Yeah, I'm really familiar with that area as I would sometimes take 26 west out of LAF...I think Warren county is the least populated county in the state. Did you contact IND about what you saw?

We were ironically on route 26 just east of Pine Village looking NW when we saw our brief touchdown...and ended up on the maze of gravel roads as the rotating wall cloud and occasional brief funnels continued to slowly move SE past Pine Village.

My friend tweeted a picture (the one I posted here) and approximate location to them. None of us had their phone number out there so when we saw the initial touchdown we called it into the local authorities. The warning was updated with confirmed tornado wording about 5 minutes after we called so we assumed that they either had our report relayed or had someone else call them.

I'll send them an email later this afternoon with a few more details than a quick tweet.

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Ah, hindsight.

 

I think Tony hit the nail on the head. Looking back at that special sounding out of DVN now, it should have had more impact on me than it did. The EML was really damn low, ~850mb. It's not a common problem to have around here, since most of the time we deal with EML bases around 700mb. But looking back at sat pics, Ma Nature was flying a strong signal yesterday with the general lack of decent cumulus fields in the uncontaminated portion of the warm sector.

 

I would guess the lack of a decent SW flow hurt the moisture quality aloft, with the outflow from the morning round of storms simply adding insult to injury (between subsidence from the MCS drying out the atmosphere and further disruption of the low-level flow).

 

And of course the lack of a decent SW flow can probably be attributed to the lack of a decent shortwave, as height falls were minimal at best.

 

As far as the low EML, I'm guessing that also goes back to the atmosphere still being somewhat worked over from the morning MCS...

 

In comparison, the atmosphere on 6/22 - 6/23/15 recovered nicely for a modest tornado outbreak in spite of fairly extensive cloud debris and the morning MCS ongoing through peak heating, thanks to a 60kt southerly LLJ and unseasonably significant height falls.

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WOOD TV out of Grand Rapids is reporting it, in SE Kent County

 

http://woodtv.com/2015/07/14/thousands-without-power-across-west-michigan/

Thanks, Stebo... that's not too far from where we are in Allegan Co. Maybe 15 miles or so as the crow flies. The storms we got here from the west weren't as bad, but the cell that popped up overhead here and then built northward toward GR got pretty scary in this sardine can "cottage" we're in!

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NWS MKX confirmed 100 MPH winds on Sunday night... bringing the total number of significant wind reports from that MCS to 3. Is that enough to be called a derecho? SPC's faq says "several" significant reports... but that's pretty vague.

I didn't even think there was requirement for "significant" reports.

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Yup

http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm

Edit: oh sweet, they updated/included more events since I last checked... including the June 30 derecho last year

Interesting. Pretty sure I've read papers in which the author(s) didn't use that criteria. I wonder if it's one of those things where there's not an "official" definition per se.

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Interesting. Pretty sure I've read papers in which the author(s) didn't use that criteria. I wonder if it's one of those things where there's not an "official" definition per se.

Yeah there's a lot of confusion/misunderstandings about the definition of a derecho. We get a good amount of long-lived severe squalls... but they rarely produce significant winds because the environment isn't good enough. In the winter of 2013-14, we had 3 of those events... they all happened because there were very strong winds off the surface and the atmosphere was just unstable enough (100-400 j/kg) to bring those winds down. Then compare that to the 10/26/10 derecho which had this environment ahead of it. Soon after this sounding, the line came through ILN's CWA and produced a couple significant wind reports (one measured 79 MPH)

dXC4V5Q.gif

 

Sorry I kinda went off on a tangent :P

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Yeah there's a lot of confusion/misunderstandings about the definition of a derecho. We get a good amount of long-lived severe squalls... but they rarely produce significant winds because the environment isn't good enough. In the winter of 2013-14, we had 3 of those events... they all happened because there were very strong winds off the surface and the atmosphere was just unstable enough (100-400 j/kg) to bring those winds down. Then compare that to the 10/26/10 derecho which had this environment ahead of it. Soon after this sounding, the line came through ILN's CWA and produced a couple significant wind reports (one measured 79 MPH)

dXC4V5Q.gif

Sorry I kinda went off on a tangent :P

Speaking of tangents, I was thinking about the November 1998 and October 2010 bombs. Both had something in common... they occurred after very robust Ninos transitioned to Ninas. I don't know if there's anything to that but it makes you wonder if Fall 2016 will feature a huge low.

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Speaking of tangents, I was thinking about the November 1998 and October 2010 bombs. Both had something in common... they occurred after very robust Ninos transitioned to Ninas. I don't know if there's anything to that but it makes you wonder if Fall 2016 will feature a huge low.

That'd be sweet. 2014 Fall severe season was a huge miss... so we're due for a hit.

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Speaking of tangents, I was thinking about the November 1998 and October 2010 bombs. Both had something in common... they occurred after very robust Ninos transitioned to Ninas. I don't know if there's anything to that but it makes you wonder if Fall 2016 will feature a huge low.

Didn't April 2011 happen after the biggest switch from El Niño to La Niña ever?

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Didn't April 2011 happen after the biggest switch from El Niño to La Niña ever?

Well 1997-1999 was a bigger Nino -> Nina switch. The one you're thinking of happened in July 2010... by the time April came around, a moderate Nina had been in place for a while. There's been case studies that link La Nina to a more active tornado season. There was also a very negative PDO. There's also been a couple of case studies that link a -PDO to more stronger tornadoes. The TNI (Trans-Nino Index) was also very positive, which has been linked to more tornadoes. Both Super Outbreaks happened when there was a moderate Nina, very -PDO, very +TNI

 

PDO-tornado connection: http://www.drroyspencer.com/2011/05/the-tornado-pacific-decadal-oscillation-connection/

TNI-tornado connection: http://cpo.noaa.gov/sites/cpo/Webcasts/MAPP/2013/Presentations/1-15/Lee.pdf

The Nina-tornado connection is widely studied I think, but here's one of the studies: http://www.spc.noaa.gov/publications/schaefer/el_nino.htm

 

The TNI one might be less known... but I think it's worth noting that, among other instances, the past 3 years (the infamous tornado drought) have been a strongly -TNI.

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Well 1997-1999 was a bigger Nino -> Nina switch. The one you're thinking of happened in July 2010... by the time April came around, a moderate Nina had been in place for a while. There's been case studies that link La Nina to a more active tornado season. There was also a very negative PDO. There's also been a couple of case studies that link a -PDO to more stronger tornadoes. The TNI (Trans-Nino Index) was also very positive, which has been linked to more tornadoes. Both Super Outbreaks happened when there was a moderate Nina, very -PDO, very +TNI

PDO-tornado connection: http://www.drroyspencer.com/2011/05/the-tornado-pacific-decadal-oscillation-connection/

TNI-tornado connection: http://cpo.noaa.gov/sites/cpo/Webcasts/MAPP/2013/Presentations/1-15/Lee.pdf

The Nina-tornado connection is widely known I think... but here's one of the studies: http://www.spc.noaa.gov/publications/schaefer/el_nino.htm

Thank you for this. I had thought it was the major switch that then down the line caused that pattern to become so hectic. That month is something I doubt I'll ever see again in my life

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