Long Lived Supercells (Was in the Forecast Room)

Published by: wktd 2010-03-19

This time lapse follows the storm motion with LSRs, warnings, radar, and watches.
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That loops is amazing! I cant believe how long it had its classic supercell shape...truly amazing! :o

Storm-Relative Flow and its Relationship to Low-Level Vorticity in ::
File Format: PDF/Adobe Acrobat - View as HTMLBlanchard 1998), and between short-lived and long-. lived supercell storms ( Bunkers et al. 2006). .. Test of helicity as a tornado forecast parameter.
http://ams.confex.com/ams/pdfpapers/142086.pdfHOME

Aaron

Severe Weather FAQ::
Supercell storms are usually isolated from other thunderstorms because it . Most tornadoes are abrupt at onset, short-lived and often obscured by rain or
http://www.newtonkansas.com/tornados.htmlHOME

May 18 - 20, 2007 Storm Chase::
I expected supercell thunderstorms but tornadoes would be less likely. The long range forecast models have been especially inaccurate this year and vary
http://www.harkphoto.com/05182007.htmlHOME

I dimly recall an 18+ hour long supercell that occured in May 1991 (or was it 1992?) that tracked from near Colorado Springs/Pueblo around 21Z and was still going strong in Arkansas around 15z the next morning. That was the longest lasting supercell I can recall, but this 6-state supercell tracked the furthest distance (that I can recall).

I recall a few long lived storms...

St. Louis -> NC
http://www.spc.noaa.gov/climo/reports/020501_rpts.html

http://www.spc.noaa.gov/climo/reports/020428_rpts.html
(the central KY-> Atl. Ocean path)

Also the OK storm from 5/29-30/2004... didn't travel as far, but it also had a storm motion nearly half of those today.

Aaron

That first one may have been the one I was thinking of, or one with a very similar track at least. Also, the May 9th, 2003 Oklahoma tornadic storm lasted about 10 hours as well...

An absolutely amazing cell yesterday. I think this storm (along with the other examples cited) proves beyond a doubt that there is really no limit: a supercell in theory can continue forever, as long as the surrounding atmospheric conditions remain favorable. Basically they go until they outrun the good air, or are choked off by competing storms.

The lifetime of individual tornadoes is another matter. The consensus seems to be that there are inherent limiting factors for tornadoes, factors that would preclude a perpetual steady-state tornado, even in theory. I'm not sure I completely buy this, but certainly very-long-track tornadoes are extremely rare. The tri-state tornado is of course the record holder, although some experts question whether this was actually a single tornado. It will be interesting to see how last night's storms stack up in comparison. In particular it will be interesting to see if the overall damage path resembles the one left by the tri-state storm. If so, it would provide some ammunition to those who think the tri-state storm was actually a family of tornadoes.

So what is the record for the most tornadoes, anyway? I'm talking about the total tornado count over the lifetime of a single cell. Anybody know, or want to take a guess? I suspect last night's cell might be in the running as one of the all-time most prolific tornado producing cells. But it's going to be a seriously time-consuming endeavor to attempt a survey of the entire track of the cell. We may never know the true numbers.

The supercell of the year is still T-warned as it slides ENE across Indiana. It should slide just south of Plymouth, if it hangs on that long. You know, if this storm can just hold on for a little longer, it will have traversed FIVE states -- Kansas, Missouri, Illinois, Indiana, and Michigan. I'm not sure what you call a storm like that. The five-state supercell? The five hundred mile storm? Has that even happened before?

It must certainly be rare, but I don't think it is unprecedented. I seem to recall a nontornadic supercell storm several years ago that traversed from somewhere in the Midwest (I think Iowa) ESE all the way to the East Coast (at least that's how I remember it, but it's fuzzy). At any rate, it is an amazing storm.

Speaking of fuzzy memory, my whole mind is pretty fuzzy right now. Just got back from a bust chase in SE KS (though we had some fun toward the end dodging hail cores and a few mesos after dark). Time for bed!

That was certainly interesting... By the way, out of all the storms that I have seen -- that supercell, when it was over Springfield, IL -- was the MOST intense storm that I have ever witnessed (obviously not as photogenic as most, with only a few glimpses of the large tornado, but still). The RFD winds immediately south of the main tornado surpassed 100mph for at least 10 seconds at my location over I-72, nearly lifting my car off the ground. Man, oh man... If it was only in the daytime, what a sight it would have been.

Well, despite my laziness to complete things... Maybe I'll do a case study on this supercell LOL. I have a ton of data available from yesterday, including just about every model run -- and every model sounding since yesterday morning (saved on my Linux box). Just wish I saved some SPC mesoanalysis graphics....

I looked back at the 0.5 degree BREF WSR-88D data archives and this was a *6-state* tornadic supercell. First echo was noted near Morrison, OK (Noble County) at 1726z/12th. Last detectable echo was just north of Jackson, MI (Jackson County) at 0904z/13th. That means this supercell tracked 794 miles (690nm) over a period of 17 hours and 38 minutes. The average heading was from 245 degrees at 45mph (39KT).

Two great radar loops of this historic, long-track tornadic supercell can be viewed on the IA State Univeristy mesonet web site here:

http://mesonet.agron.iastate.edu/cases/060312/supercell/

This time lapse follows the storm motion with LSRs, warnings, radar, and watches.

I dimly recall an 18+ hour long supercell that occured in May 1991 (or was it 1992?) that tracked from near Colorado Springs/Pueblo around 21Z and was still going strong in Arkansas around 15z the next morning. That was the longest lasting supercell I can recall, but this 6-state supercell tracked the furthest distance (that I can recall).
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I thought the May 29, 2001 Tulia-Turkey-Childress supercell was an extreme long-lived event. This one beat it by a wide margin.

Dave Kaplow commented about how in theory a supercell could continue forever. Seemingly things have to be just right for that to happen, though. While Roger Edwards, Rich Thompson, and I were being chased by the long-lived storm on 5/29/2001, several other supercells north of us lined out after a relatively few hours. Something in the environment that day (subtle differences in moisture or shear?) alllowed our storm to continue while allowing the others to line out.

Speaking of squall lines, has anyone looked at similar stats for them? The May 3-4, 1989 derecho line moved from north of Amarillo to New Orleans, while the 5/27/2001 People Chaser went from southwestern Kansas to the Gulf of Mexico. However, I'd be surprised if those were even close to record distances.

Tropical cyclones can also in theory last a very long time, but in practice its very hard to keep one over unobstructed tropical waters for a prolonged time. Ginger of 1971 (Atlantic) and John of 1994 (Pacific) both lasted about a month, which is the known record.

Jack Beven
Tropical Prediction Center