When will we reenter an active severe cycle? (1 Viewer)

When will once again see large-scale outbreaks similar to those of 2008–14?


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Now that the recent +PDO trend since 2013 seems to be reversing itself, given -ENSO/-PMM in place as well, one may reasonably ask whether the background state will begin to favour large-scale outbreaks with multiple long-tracked supercells each producing one or more EF4+ tornadoes. By “active severe cycle,” I am referring to a period with outbreaks like those of 21–22 March 1932, 11–12 April 1965 (Palm Sunday II), 3–4 April 1974 (first Super Outbreak), 26 April 1991, 3 May 1999, 5–6 February 2008 (Super Tuesday), 27–28 April 2011 (second Super Outbreak), 24 May 2011, 27–28 April 2014, and so on. We have certainly seen significant events since 2014, but these have mostly been confined to localised, isolated, outstanding supercells that produce a violent tornado or two, rather than multiple, long-lived, violent families.
 
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I believe our long-range severe guru @andyhb touched on this in another thread...apparently despite the flip back to -PDO, the indicators aren't exactly looking great if you're looking for big dog severe next spring. We're still pretty much in voodoo territory in that regard, though. I might give the long-range EPS and CFS a little credit at 2-3 months lead time, but 6?
 
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I believe our long-range severe guru @andyhb touched on this in another thread...apparently despite the flip back to -PDO, the indicators aren't exactly looking great if you're looking for big dog severe next spring. We're still pretty much in voodoo territory in that regard, though. I might give the long-range EPS and CFS a little credit at 2-3 months lead time, but 6?
I wonder why the dearth of large-scale, major outbreaks is forecast to persist under a completely different pattern from that of 2015–20. Since 2015 we have been in a +PDO/+PMM regime. Now we are entering a -PDO/-PMM regime, coupled with a solid -ENSO. Yet the climate models continue to depict a stubbornly inactive pattern in terms of high-end severe-weather episodes. What, logically, could be the cause of this? The pattern has changed considerably, yet the results are still the same. Hmm.
 
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I wonder why the dearth of large-scale, major outbreaks is forecast to persist under a completely different pattern from that of 2015–20. Since 2015 we have been in a +PDO/+PMM regime. Now we are entering a -PDO/-PMM regime, coupled with a solid -ENSO. Yet the climate models continue to depict a stubbornly inactive pattern in terms of high-end severe-weather episodes. What, logically, could be the cause of this? The pattern has changed considerably, yet the results are still the same. Hmm.
@andyhb
 

Kory

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I wonder why the dearth of large-scale, major outbreaks is forecast to persist under a completely different pattern from that of 2015–20. Since 2015 we have been in a +PDO/+PMM regime. Now we are entering a -PDO/-PMM regime, coupled with a solid -ENSO. Yet the climate models continue to depict a stubbornly inactive pattern in terms of high-end severe-weather episodes. What, logically, could be the cause of this? The pattern has changed considerably, yet the results are still the same. Hmm.
Where are you coming up with this?
 

andyhb

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The question posed in the thread title is not one that can be answered with any degree of accuracy. We lack the tools to be able to reliably forecast severe weather activity relative to "normal" at those ranges.
 
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Ironically we may have our answer just two days later with the way this has overachieved...we'll see what happens next spring.
For this event to meet my definition of a top-tier outbreak, it would need to have spawned multiple EF4+ tornadoes from separate supercells. A single supercell generating multiple violent tornadoes (i.e., the recent long-tracker in MO, TN, and KY) would not meet my criteria. However, if the supercells that struck Defiance MO and Bowling Green KY generated EF4+ tornadoes as well—which is yet to be determined—then this outbreak would count as a top-tier event. The event has already proven to have been significant and tragic, but whether it can called a top-tier outbreak is yet to be seen.
 
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Ironically we may have our answer just two days later with the way this has overachieved...we'll see what happens next spring.
Ironically we may have our answer just two days later with the way this has overachieved...we'll see what happens next spring.
Way this la Niña is going. We may not have to wait to spring . I can see more big outbreaks Down road this winter particularly in south
 

Fred Gossage

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For this event to meet my definition of a top-tier outbreak, it would need to have spawned multiple EF4+ tornadoes from separate supercells. A single supercell generating multiple violent tornadoes (i.e., the recent long-tracker in MO, TN, and KY) would not meet my criteria. However, if the supercells that struck Defiance MO and Bowling Green KY generated EF4+ tornadoes as well—which is yet to be determined—then this outbreak would count as a top-tier event. The event has already proven to have been significant and tragic, but whether it can called a top-tier outbreak is yet to be seen.
I think you have an overwhelmingly, devastatingly horrible misunderstanding of just how rare the type of outbreak you're looking for actually is in the United States. Since the mid/late 1880s, we average a tornado outbreak with five or more violent-rated tornadoes... something on the caliber of Super Tuesday 2008, May 4 2003, etc... once every 9-15 years. There is occasionally a sequence where they are more frequent, such as 2003-2008-2011, but that is the long term average. Having a gap in that level of event since 2011 is climatologically very normal based on over 100 years of tornado records... but it also suggests that we are rapidly nearing the end of that.
 

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Taking the opinions of Ryan Maue and Mike Smith seriously on climate change is nonsense.
 

Kory

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Believing FEMA/federal government is actually competent in managing the aftermath of a disaster is a joke...the folks in Louisiana have been abandoned after Hurricane Ida. But that's a topic for another time.
 
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Taking the opinions of Ryan Maue and Mike Smith seriously on climate change is nonsense.
In a 2007 interview on The Larry King Show, Lindzen said:[69] And if we had warming, it should be accomplished by less storminess. ...the physics says we should see less.
https://en.wikipedia.org/w/index.php?title=Richard_Lindzen&oldid=1059862525#Views_on_climate_change

Frankly, I am tired of the MSM attributing every severe-weather episode to climate change. If anything, the evidence suggests an inverse correlation.
 

andyhb

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All of these are climate change deniers. Do better.
If the scientific basis is sound, then I don’t need to do so.
If the models are correct, global warming reduces the temperature differences between the poles and the equator. When you have less difference in temperature, you have less excitation of extratropical storms, not more. And, in fact, model runs support this conclusion. Alarmists have drawn some support for increased claims of tropical storminess from a casual claim by Sir John Houghton of the U.N.'s Intergovernmental Panel on Climate Change (IPCC) that a warmer world would have more evaporation, with latent heat providing more energy for disturbances. The problem with this is that the ability of evaporation to drive tropical storms relies not only on temperature but humidity as well, and calls for drier, less humid air. Claims for starkly higher temperatures are based upon there being more humidity, not less -- hardly a case for more storminess with global warming.
http://www.heatisonline.org/contentserver/objecthandlers/index.cfm?id=5903&method=full

For the record, none of those three personages actually denies that warming is occurring, but contests the media and government’s role in skewering interpretations.
 

andyhb

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I'd really love to know where he's getting the "drier, less humid air" idea from considering the air's ability to hold water vapor increases with increasing temperature. This is basic Clausius-Clapeyron physics.
 
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I do wonder how much climate change is going to have on the distribution and intensity of tornadoes and tornado outbreaks; Grazulis posted some stuff on his Twitter that showed a trend that climate change might kill spring chasing, among other things. I wonder if tornadoes in America will shift locations as to areas where they most commonly occur (Dixie taking the Plains' place as the main hotspot for tornadoes, for instance) and maybe tornadoes and major outbreaks may not occur as often but when they do they will be much more powerful and intense (I think climate change has had that effect on hurricane frequency and intensity, actually). Perhaps violent outbreaks of tornadoes in unexpected places will happen more often? No clue, just thinking out loud.
 
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I do wonder how much climate change is going to have on the distribution and intensity of tornadoes and tornado outbreaks; Grazulis posted some stuff on his Twitter that showed a trend that climate change might kill spring chasing, among other things. I wonder if tornadoes in America will shift locations as to areas where they most commonly occur (Dixie taking the Plains' place as the main hotspot for tornadoes, for instance) and maybe tornadoes and major outbreaks may not occur as often but when they do they will be much more powerful and intense (I think climate change has had that effect on hurricane frequency and intensity, actually). Perhaps violent outbreaks of tornadoes in unexpected places will happen more often? No clue, just thinking out loud.

That certainly seems to be the trend given the last few years. It feels like chasers have to be ready to go anytime, anywhere if they want to get the good stuff. Taking a week or two in the Plains in May or early June just doesn't cut it anymore. Case in point, I was shocked by the number of chasers out Friday night (and many of them not local to the affected area) for what was sure to be an after-dark event with highway-speed storms (and no guarantee of a classic mode, I was thinking any significant tornadoes were likely to be shrouded in mist like the 3/25 Alabama long-tracker) and two major river valleys/crossings to contend with. There was a time, not so long ago, when chasing an event like this was something that just wasn't done even by the most veteran chasers (unless maybe if it was in your backyard).
 

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