Severe Weather 2022

[Richardjacks]

Someone needs to make a thread for Tuesday/Wednesday. You know it will not be me.

I can! Oh wait...

 

[akt1985]

I see that there is now a chance of thunderstorms next Saturday 4/2 for north Alabama. Is this the system that everyone is concerned with?

 

[Fred Gossage]

I see that there is now a chance of thunderstorms next Saturday 4/2 for north Alabama. Is this the system that everyone is concerned with?

That system has trended toward being sheared out. However, teleconnections, MJO progression, and the overall pattern as a whole makes it look like the next few weeks may very well be fairly active.

 

[Casuarina Head]

That system has trended toward being sheared out. However, teleconnections, MJO progression, and the overall pattern as a whole makes it look like the next few weeks may very well be fairly active.

I understand that I will be criticised for saying this, but this has been happening abnormally frequently, at least this winter, under an otherwise conducive -PDO/-ENSO setup. With an exception or two, have been seeing a lot of high-amplitude, meridional, sheared-out systems this winter instead of low-amplitude, latitudinal, consolidated systems. Normally, a near-record-breaking -PDO combined with a solid Niña would be producing something closer to what was observed during the winters of 1999, 2008, etc. I think that global warming is altering the background state due to expanding Hadley cells and warming seas (Indian-Pacific) and is thus leading to more high-latitude blocking and fewer synoptic-scale setups that are conducive to widespread outbreaks with multiple cyclic storms over a broad area vs. an isolated significant tornado or two. The December 2021 outbreak, like Easter 2020, was an exception to the otherwise pronounced downtrend in large-scale events since 2012, regardless of ENSO and PDO.

 

[pohnpei]

I understand that I will be criticised for saying this, but this has been happening abnormally frequently, at least this winter, under an otherwise conducive -PDO/-ENSO setup. With an exception or two, have been seeing a lot of high-amplitude, meridional, sheared-out systems this winter instead of low-amplitude, latitudinal, consolidated systems. Normally, a near-record-breaking -PDO combined with a solid Niña would be producing something closer to what was observed during the winters of 1999, 2008, etc. I think that global warming is altering the background state due to expanding Hadley cells and warming seas (Indian-Pacific) and is thus leading to more high-latitude blocking and fewer synoptic-scale setups that are conducive to widespread outbreaks with multiple cyclic storms over a broad area vs. an isolated significant tornado or two. The December 2021 outbreak, like Easter 2020, was an exception to the otherwise pronounced downtrend in large-scale events since 2012, regardless of ENSO and PDO.

Late 1955-early 1956, Late 1988-early 1989 Both negative PDO combined with soild Nina didn't produce the high end outbreak you definite. This negative PDO/Nina period already had 12/10 outbreak which was historic and unprecedented for winter season.
The conclusion you made was possible theoretically, but I don't believe the whole evolution of the climate system is as simple as you said.
All these high TNI/negative PDO things was more about possiblity. I don't think there was a certain setup ought to produce historic outbreaks.

 

[tennessee storm chaser]

Going into April top analog seems be april 2006, that had bad outbreak with 60 percent tornado probs , crazy

 

[Casuarina Head]

Late 1955-early 1956, Late 1988-early 1989 Both negative PDO combined with soild Nina didn't produce the high end outbreak you definite. This negative PDO/Nina period already had 12/10 outbreak which was historic and unprecedented for winter season.
The conclusion you made was possible theoretically, but I don't believe the whole evolution of the climate system is as simple as you said.
All these high TNI/negative PDO things was more about possiblity. I don't think there was a certain setup ought to produce historic outbreaks.

The winter of 1955–6 actually did feature one or more significant outbreaks on 15–16 Nov ‘55 (eight F2+ tornadoes, including three F3s, per Grazulis [1993], p. 991) and 24–25 Feb ‘56 (14 F2+ tornadoes, including two F4s, per Grazulis [‘93], p. 992). Springtime ‘56 also began with the major outbreak of 2–3 Apr (33 F2+ tornadoes, including nine or more violent tornadoes, depending on sources ranging from the NWS to EJSSM and Grazulis [‘93]).

My point still stands, however, that strong -PDO/Niña combinations, along with the +TNI that you mentioned, almost always feature one or more big wintertime outbreaks, and often generate multiple such events. If not, the following spring usually delivers in terms of multiple big events. Yet -PDO/-ENSO/+TNI combinations in a warming climate no longer seem to deliver top-tier outbreaks in terms of intensity and geographic scope as often.

If I recall correctly, Thomas Grazulis has tweeted about his research’s having implied that climate change may result in lower frequencies of high-end, widespread outbreaks, though the few that do occur may be more severe within concentrated areas/timescales and occur “out of season” more often. Since Palm Sunday ‘65 the gap between major events has accentuated as planetary-scale warming (especially in the Indian-Pacific area) has ensued.

 

[MichelleH]

Between the Enigma Outbreak of February 19, 1884 and the outbreak of March 21, 1932 was a span of 48 years, between March 21, 1932 and April 3, 1974 was a span of 42 years and between April 3, 1974 and April 27, 2011 was a span of 37 years. The gap is lessening and this is just the major outbreaks, not counting the lesser outbreaks. Climate changes - that's what it does - and things cycle. The first English settlers of this nation recorded tornado events as well. It is sheer hubris to think humans have any control of the weather.

 

[CheeselandSkies]

That system has trended toward being sheared out. However, teleconnections, MJO progression, and the overall pattern as a whole makes it look like the next few weeks may very well be fairly active.

Looks like that system got pushed back to around 4/4-4/5 on the GFS. Then there are hints of another one possibly around the 10th. Also some hints that one or both of these troughs may not be as highly amped with a squashed E-W wavelength.

 

[Fred Gossage]

Looks like that system got pushed back to around 4/4-4/5 on the GFS. Then there are hints of another one possibly around the 10th. Also some hints that one or both of these troughs may not be as highly amped with a squashed E-W wavelength.

I actually think that timing may be a bit too fast, and it looks too fast when looking at the ensemble data. The period from the 3rd to probably the 6th or 7th is going to be about the -NAO coming to the end, but it's going to take a few days to do it. The big start of April troughing in the east shifts northeastward, and that dislodges the ridging over Greenland. I wouldn't rule out a threat (maybe even a significant one) around the 7th-8th or so right after the -NAO weakens. From there on out, all ensemble data is screamingly consistent (run to run and ensemble family to ensemble family) that the whole pattern lays down and goes low amplitude, the classic low amplitude pattern that you would expect during a strong -PDO, a firmly established La Nina and a high-end +TNI spike. This is honestly acting much more like a first-year La Nina than a second-year, which isn't too much of a surprise given that last year acted more like a Nino than a Nina with the subtropical interference, the consistent -SOI, etc. That concerns me because when this does go low amplitude, we aren't just going to strongly ridge out and all this shift northwest of Dixie Alley.

 

[DetectiveWX]

I actually think that timing may be a bit too fast, and it looks too fast when looking at the ensemble data. The period from the 3rd to probably the 6th or 7th is going to be about the -NAO coming to the end, but it's going to take a few days to do it. The big start of April troughing in the east shifts northeastward, and that dislodges the ridging over Greenland. I wouldn't rule out a threat (maybe even a significant one) around the 7th-8th or so right after the -NAO weakens. From there on out, all ensemble data is screamingly consistent (run to run and ensemble family to ensemble family) that the whole pattern lays down and goes low amplitude, the classic low amplitude pattern that you would expect during a strong -PDO, a firmly established La Nina and a high-end +TNI spike. This is honestly acting much more like a first-year La Nina than a second-year, which isn't too much of a surprise given that last year acted more like a Nino than a Nina with the subtropical interference, the consistent -SOI, etc. That concerns me because when this does go low amplitude, we aren't just going to strongly ridge out and all this shift northwest of Dixie Alley.

In other words, Deep South and OH Valley are stuck with high-end severe risk like it was back in last half of April 2011?

 

[Fred Gossage]

In other words, Deep South and OH Valley are stuck with high-end severe risk like it was back in last half of April 2011?

Not in the same universe as what I'm saying. Welcome to the forum, but please sit back and lay off the mass death and destruction. Not every severe weather pattern will be that.

 

[CheeselandSkies]

4/27/11 was such an extreme outlier, that there is plenty of room for outbreaks that are well short of that threshold yet still plenty impactful and dangerous in their own right. We just had a good example of one in December.

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[DetectiveWX]

Ok I'll lay off the extremes. My bad.

 

[Fred Gossage]

4/27/11 was such an extreme outlier, that there is plenty of room for outbreaks that are well short of that threshold yet still plenty impactful and dangerous in their own right. We just had a good example of one in December.

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Right. You can take 4/27/11 and cut it into just a third, and you'd still end up with a day that has as many EF4+ tornadoes as days like Super Tuesday 2008, May 4 2003, etc. You can take just a small fraction of 4/27/11 and have a fully verified SPC High Risk tornado outbreak event.

 

[tennessee storm chaser]

What amazing , as bad as April 27. 2011 was , the system think it was April 6. 2006 actually had a higher ceiling , with 60 percent tornado probs , almost unheard of course it didn’t quiet pan out that way but still significant everything popped up that day went to rotation quick , with plenty spacing for long tracking violent tornadoes. And 2006 April keeps popping up top analog for this coming April . Interesting

 

[CheeselandSkies]

What amazing , as bad as April 27. 2011 was , the system think it was April 6. 2006 actually had a higher ceiling , with 60 percent tornado probs , almost unheard of course it didn’t quiet pan out that way but still significant everything popped up that day went to rotation quick , with plenty spacing for long tracking violent tornadoes. And 2006 April keeps popping up top analog for this coming April . Interesting

Just hope that analog doesn't extend into the following month (May 2006 flipped to eastern troughing and was horrible for chasing).

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[Fred Gossage]

What amazing , as bad as April 27. 2011 was , the system think it was April 6. 2006 actually had a higher ceiling , with 60 percent tornado probs , almost unheard of course it didn’t quiet pan out that way but still significant everything popped up that day went to rotation quick , with plenty spacing for long tracking violent tornadoes. And 2006 April keeps popping up top analog for this coming April . Interesting

Where and from whom?

April 2006 was ENSO neutral after coming out of a brief, weak La Nina that had previously registered as neutral peak in previous climo sets, that was sandwiched between two El Ninos... with a firmly negative TNI and a neutral to positive PDO in place. From December 2005 to May 2006, the lowest the PDO got in that whole period was -0.04. Not a good match to what we have in place right now, especially in terms of the things that drive a severe weather pattern. Spring 2006 was much less favorable in a classically speaking sense than what this is.

 

[tennessee storm chaser]

Where and from whom?

April 2006 was ENSO neutral after coming out of a brief, weak La Nina that had previously registered as neutral peak in previous climo sets, that was sandwiched between two El Ninos... with a firmly negative TNI and a neutral to positive PDO in place. From December 2005 to May 2006, the lowest the PDO got in that whole period was -0.04. Not a good match to what we have in place right now, especially in terms of the things that drive a severe weather pattern. Spring 2006 was much less favorable in a classically speaking sense than what this is.

What was thinking be honest , read it over on couple other weather forums be honest…

 

[Fred Gossage]

While we are briefly mentioning April 2006 and that outbreak on the 7th in particular, let's be clear. It did NOT have a higher ceiling than 4/27/11 just because there was a 60% tornado risk issued. 2006 was a season that was characterized by boundary layer moisture mixing issues with every system, despite there being multiple active systems. 4/7/06, in particular, had a warm sector with dewpoints that mixed out into the upper 50s before the 20z Day 1 got the upgrade to the 60% tornado risk. There was also veered low-level flow that evolved mid-event prior to the 60% tornado risk upgrade in the afternoon. The midday and early afternoon portion of the outbreak (the Tennessee part) was indeed a swarm of spaced and discrete cells, but the wave that actually prompted Broyles to issue the 60% risk was a mess of closely spaced HP supercells. There was a total of 73 tornadoes from the three-day outbreak overall. It definitely was an outbreak. It deserved the High Risk that was issued. However, the majority of the tornadoes in the outbreak were lower-end. Despite the Day 2 High Risk (first of only two ever issued) and the 60% tornado risk at 20z on the 7th (the only one EVER issued), the entire three-day stretch only had two tornadoes rank F3, and there were none that were ranked as violent. A forecaster's response to an event does not equal an event's actual potential or outcome.