Massachusetts Tornado - 1 Year Later

[CT Rain]

By the way, good write up about the day too. I enjoyed it. You are right that it will be close to impossible at this point to say whether or not a boundary was at work. Obviously the lowest portion of tornadogenesis remains elusive and is the subject of a lot of research lately. The balance of near-ground parcels with the most positive buoyancy/least M and high angular momentum air being entrained (usually with a second RFD) coupled with an organized / stacked circulation(s) above remains the domain of this issue. Small things like elevation, surface friction etc. are likely factors when you think about the layer near the ground having a significant role in the ability for updrafts to be sustained into the increasing M state.

Good post. Discriminating between tornadic and non-tornadic supercells and what makes tornadogesis go is obviously the big research topic at the present time.

Look at how well documented with observations some of the VORTEX-2 tornadoes are and it's still unclear which factors tip the scale.

[HM]

With respect to the channeled flow...

The feeling among us was that the parameters in place were sufficient to generate a strong tornado regardless of the terrain. Having looked at as much local radar data as I have, watching storms descend the east slope into the valley I do think there is the chance that this may have helped a bit, but the point is that it is speculative and very difficult to prove either way. Anecdotally, and perhaps statistically albeit with little significance, we do tend to see tornadoes more frequently in the N-S running valleys, and the Bosart paper addresses that. However in this case, rather than introduce a fairly uncertain section we initially elected to leave it out entirely. Upon review it was suggested to us to mention it... again, we didn't dispute the idea that it might be a factor, and that gave us an opportunity to introduce it at the behest of a reviewer with the caveat that we couldn't say for sure it's influence.

It's still amazing to see the tornado rip up the hill sides once it got east of Springfield. Perhaps the channeled flow helps in facilitating tornadogenesis, but the atmospheric environment was practically ideal in maintaining the supercell as it moved east. IIRC, the shear at 925mb increased by a good deal from 18z through 00z that day. You are also going into a prime time of day and well removed from any marine influence.

While everything you guys are saying is 100% accurate and obviously the role of topography remains uncertain, I could actually argue against, "everything besides topography was favorable for strong tornadoes so..." type comments. Yes, everything else indicated discrete supercells with strong mesocyclones were possible to likely but those same factors cannot actually tell you if tornadogenesis will or will not happen. Obviously, the likelihood increases with parameters such as the ones present on 6/11' but you cannot actually say they were the cause too. Plenty of new research, particularly from the Markowski clan, show that all of these favorable environmental factors can or cannnot lead to a tornado. They even compared 2 supercells of similar strength and rotation where one produced a strong tornado and the other did not. I am very much looking forward to the PFT and topography work ahead because I think it could tie into the ongoing research above the lowest levels of tornadogenesis.

[CT Rain]

One thing I would like to see is a more complete climatology on storm mode linear vs discrete in the NE US. Storm mode is obviously a challenge to forecast and I wonder what the results would be when you narrow the domain to just the NE US.

[CT Rain]

While everything you guys are saying is 100% accurate and obviously the role of topography remains uncertain, I could actually argue against, "everything besides topography was favorable for strong tornadoes so..." type comments. Yes, everything else indicated discrete supercells with strong mesocyclones were possible to likely but those same factors cannot actually tell you if tornadogenesis will or will not happen. Obviously, the likelihood increases with parameters such as the ones present on 6/11' but you cannot actually say they were the cause too. Plenty of new research, particularly from the Markowski clan, show that all of these favorable environmental factors can or cannnot lead to a tornado. They even compared 2 supercells of similar strength and rotation where one produced a strong tornado and the other did not. I am very much looking forward to the PFT and topography work ahead because I think it could tie into the ongoing research above the lowest levels of tornadogenesis.

Yeah this is what I was talking about in my writeup - but it was speculative. As I said before without a denser mesoscale obs network it's hard to say one way or another wrt tornadogesis in this case. But yeah the research I've seen of late from Markowkski in particular is very interesting. Synoptic environment is clearly important but won't separate tornadic vs nontornadic supercells.

[CoastalWx]

Yeah maybe it needed a kick start? I think the presence of that supercell to the north putting down several outflow boundaries may have been important in getting the southern storm to take off and go tornadic. A feed of relatively higher theta-e air right up the CT River valley with a slightly backed trajectory could have been a factor but we'll never know for sure.

Yeah I wish we had a few obs in that area to tell of that happened. Even PV thinking allows a stretching of air off the mtns to the west. It's not a classic example and the contribution of it could be minimal, but convection is a fickle thing and sometimes the smallest things initiate it.

I also don't know how the obs the Lance suggested would be telling of the PFT before and after since some of those obs can have bizzare wind directions given their location. At least BDL and ALB are in larger valleys and not prone to subtle wind direction changes.

[HM]

Good post. Discriminating between tornadic and non-tornadic supercells and what makes tornadogesis go is obviously the big research topic at the present time.

Look at how well documented with observations some of the VORTEX-2 tornadoes are and it's still unclear which factors tip the scale.

Very true. Even with their efforts, there were numerous issues with data retrieval and manipulation. Basically, most of their criticism came from that end of things. Therefore, there is no way an analysis of that caliber could take place with the 6/11' event.

[CT Rain]

Yeah I wish we had a few obs in that area to tell of that happened. Even PV thinking allows a stretching of air off the mtns to the west. It's not a classic example and the contribution of it could be minimal, but convection is a fickle thing and sometimes the smallest things initiate it.

I also don't know how the obs the Lance suggested would be telling of the PFT before and after since some of those obs can have bizzare wind directions given their location. At least BDL and ALB are in larger valleys and now prone to subtle wind direction changes.

I think you can even look at earlier that day... 45 minutes prior the Northampton supercell had a tight low level mesocyclone yet it didn't go tornadic. The low level shear did increase over the subsquent 45 minutes but I'd argue that some type of sub mesoscale process... OFB interaction?? may have been important.

All of this though is beyond the scope of the paper as the authors discussed. So none of this is in any way a criticism... just the opposite in fact... continuing the discussion and speculating.

[CoastalWx]

While everything you guys are saying is 100% accurate and obviously the role of topography remains uncertain, I could actually argue against, "everything besides topography was favorable for strong tornadoes so..." type comments. Yes, everything else indicated discrete supercells with strong mesocyclones were possible to likely but those same factors cannot actually tell you if tornadogenesis will or will not happen. Obviously, the likelihood increases with parameters such as the ones present on 6/11' but you cannot actually say they were the cause too. Plenty of new research, particularly from the Markowski clan, show that all of these favorable environmental factors can or cannnot lead to a tornado. They even compared 2 supercells of similar strength and rotation where one produced a strong tornado and the other did not. I am very much looking forward to the PFT and topography work ahead because I think it could tie into the ongoing research above the lowest levels of tornadogenesis.

Well that's why I said "perhaps." We really don't know..it's theory and on going research.

[Sugarloaf1989]

I drove up to Monson with my son three days after the tornado hit and we donated some non-perishable food items to the church/foodbank. Tolland had sent crews up across the state line to help and we figured that the tornado's could just as well have moved across Northern Connecticut and then we would need help. It's incredible how concentrated tornado damage can be as you move a very short distance from a zone of untouched area to one of utter devestation.

This is a cool picture of the path that the tornado took, if it's been posted I am sorry for that:

[HM]

Well that's why I said "perhaps." We really don't know..it's theory and on going research.

I'm sorry for the confusion. I didn't mean that against your "perhaps statement" but toward taking away anything microscale/topography related and saying that environmental factors were favorable for tornadoes anyway without it.

So actually, I was arguing for your perhaps statement to some extent.

[CoastalWx]

I think you can even look at earlier that day... 45 minutes prior the Northampton supercell had a tight low level mesocyclone yet it didn't go tornadic. The low level shear did increase over the subsquent 45 minutes but I'd argue that some type of sub mesoscale process... OFB interaction?? may have been important.

All of this though is beyond the scope of the paper as the authors discussed. So none of this is in any way a criticism... just the opposite in fact... continuing the discussion and speculating.

If there is one thing I've learned over the last two years...convection is an interesting topic. Even in HMs example of comparing two similar supercells....the most subtle discrepancies can make the difference between tornadic and non-tornadic. Likewise the most subtle discrepancies can initiate tornadogenesis. Although the environment may be suitable to maintain sups once they get going...mesoscale features are sometimes the difference in whether or not it drops a tornado.

As far as forecasting goes, all we can say is that a certain synoptic environment is or is not conducive to severe wx and tornadoes. Papers like this help us understand the actual setup and even give insight to perhaps how and why this specific example formed.

[CoastalWx]

I'm sorry for the confusion. I didn't mean that against your "perhaps statement" but toward taking away anything microscale/topography related and saying that environmental factors were favorable for tornadoes anyway without it.

So actually, I was arguing for your perhaps statement to some extent.

I probably wasn't clear either..lol. It's all good. I just meant that once it got going, the overall setup and past climo would say that a supercell can probably maintain itself given the combo of strong CAPE and shear. Obviously it's not certain that every cell would behave that way...just that the environment would support it.

[radarman]

While everything you guys are saying is 100% accurate and obviously the role of topography remains uncertain, I could actually argue against, "everything besides topography was favorable for strong tornadoes so..." type comments. Yes, everything else indicated discrete supercells with strong mesocyclones were possible to likely but those same factors cannot actually tell you if tornadogenesis will or will not happen. Obviously, the likelihood increases with parameters such as the ones present on 6/11' but you cannot actually say they were the cause too. Plenty of new research, particularly from the Markowski clan, show that all of these favorable environmental factors can or cannnot lead to a tornado. They even compared 2 supercells of similar strength and rotation where one produced a strong tornado and the other did not. I am very much looking forward to the PFT and topography work ahead because I think it could tie into the ongoing research above the lowest levels of tornadogenesis.

Well it's a bit of minutia, but I said the parameters were "sufficient" and not "favorable". I am in full agreement with the comment however that parameters alone don't explain why some cases turn out to be null and others put down tornadoes. I have good examples of this from our work in Oklahoma especially where we have more samples.

Looking at the full case of June 1st, I see strong rotation and a hook echo present well before even the Northampton supercell, way up over the Berkshires. Without any way to back this up, I believe that the destructive interference from the Northampton supercell to the south may have prevented that from going tornadic before it ever hit the valley, and in turn the Springfield storm may have robbed the Noho storm. Remember this was really a quasi-linear storm mode initially, and really only later did we see the southern most storms break off into something "discrete".

As the valley funnels to the north, one would expect the low-level velocities to increase up there, but yet those weakened and further south strengthened. In this case, I think the being the southern-most recipient of unimpeded moisture influx may have been the biggest factor, although there is definitely a chance that outflow boundaries from the earlier storms to the north could have helped, and certainly most storms in those positions would put down E-W running outflow in about the right place. Unfortunately, from the MA1 radar perspective we are looking through the main rain shield and experiencing intense radome attenuation in the early stages of the Springfield tornado, which effectively reduced the sensitivity enough to make the outflow signature weaker than the noise floor. In good conditions we can see those pretty well...

[CT Rain]

Well that's why I said "perhaps." We really don't know..it's theory and on going research.

Yeah... what we DO know is that there were some storm scale/sub mesoscale interactions that helped lead to tornadogenesis. What those were we'll just never know.

We can take some guesses based on previous research (several Bosart papers on channeled flow) or the presence of a supercell just north of where tornadogesis occurred that may have put down some sort of boundary (which would agree with latest research from Markowski on sig tornado tornadogenesis).

So our discussion is in the realm of speculation beyond the scope of the paper... but nonetheless interesting stuff.

[CoastalWx]

Yeah... what we DO know is that there were some storm scale/sub mesoscale interactions that helped lead to tornadogenesis. What those were we'll just never know.

We can take some guesses based on previous research (several Bosart papers on channeled flow) or the presence of a supercell just north of where tornadogesis occurred that may have put down some sort of boundary (which would agree with latest research from Markowski on sig tornado tornadogenesis).

So our discussion is in the realm of speculation beyond the scope of the paper... but nonetheless interesting stuff.

What was Markowski's arguments? I've never read his stuff..other than a paper on dry air and lapse rates. Even in his paper..his argument is that dry air does not work to lower lapse rates....but I can't help but think in strong tstms...it very well might. I'm no expert like he is, but looking at it from a physical standpoint.

[CT Rain]

What was Markowski's arguments? I've never read his stuff..other than a paper on dry air and lapse rates. Even in his paper..his argument is that dry air does not work to lower lapse rates....but I can't help but think in strong tstms...it very well might. I'm no expert like he is, but looking at it from a physical standpoint.

He's had a lot of great stuff recently. The older stuff from VORTEX-95 was about the presence of outflow boundaries or other areas of enhanced horizontal vorticity around storms that went tornadic. There was a really impressive number of sig tornadoes that stemmed from OFB interaction in the storms that they studied.

[CoastalWx]

He's had a lot of great stuff recently. The older stuff from VORTEX-95 was about the presence of outflow boundaries or other areas of enhanced horizontal vorticity around storms that went tornadic. There was a really impressive number of sig tornadoes that stemmed from OFB interaction in the storms that they studied.

Joplin always comes to mind.

I'll have to look. I've heard of him...but never read much of his stuff. I'll give it a look.

[CT Rain]

Joplin always comes to mind.

I'll have to look. I've heard of him...but never read much of his stuff. I'll give it a look.

The 2009 paper that he coauthored with Yvette Richardson (A phenomenal professor!!!) on the current understanding of tornadogenesis is wonderful. A good place to start and then go from there.

http://bricker.met.psu.edu/~marko/pubs/2009/MR09ATMOSRES.pdf

[HM]

Well it's a bit of minutia, but I said the parameters were "sufficient" and not "favorable". I am in full agreement with the comment however that parameters alone don't explain why some cases turn out to be null and others put down tornadoes. I have good examples of this from our work in Oklahoma especially where we have more samples.

Looking at the full case of June 1st, I see strong rotation and a hook echo present well before even the Northampton supercell, way up over the Berkshires. Without any way to back this up, I believe that the destructive interference from the Northampton supercell to the south may have prevented that from going tornadic before it ever hit the valley, and in turn the Springfield storm may have robbed the Noho storm. Remember this was really a quasi-linear storm mode initially, and really only later did we see the southern most storms break off into something "discrete".

As the valley funnels to the north, one would expect the low-level velocities to increase up there, but yet those weakened and further south strengthened. In this case, I think the being the southern-most recipient of unimpeded moisture influx may have been the biggest factor, although there is definitely a chance that outflow boundaries from the earlier storms to the north could have helped, and certainly most storms in those positions would put down E-W running outflow in about the right place. Unfortunately, from the MA1 radar perspective we are looking through the main rain shield and experiencing intense radome attenuation in the early stages of the Springfield tornado, which effectively reduced the sensitivity enough to make the outflow signature weaker than the noise floor. In good conditions we can see those pretty well...

Thanks for the post, good stuff, and I agree with everything you said. Good point about the radar.

[CT Rain]

As the valley funnels to the north, one would expect the low-level velocities to increase up there, but yet those weakened and further south strengthened. In this case, I think the being the southern-most recipient of unimpeded moisture influx may have been the biggest factor, although there is definitely a chance that outflow boundaries from the earlier storms to the north could have helped, and certainly most storms in those positions would put down E-W running outflow in about the right place. Unfortunately, from the MA1 radar perspective we are looking through the main rain shield and experiencing intense radome attenuation in the early stages of the Springfield tornado, which effectively reduced the sensitivity enough to make the outflow signature weaker than the noise floor. In good conditions we can see those pretty well...

Part of the reason for the strengthening in the valley may have been the channeling PLUS the developing inflow up the N-S river valley with basically a highway of high theta-e air right up 91.

[CT Rain]

Love the TBSS off the debris ball. That's wild.

[CoastalWx]

Love the TBSS off the debris ball. That's wild.

That's wild.

[CoastalWx]

The 2009 paper that he coauthored with Yvette Richardson (A phenomenal professor!!!) on the current understanding of tornadogenesis is wonderful. A good place to start and then go from there.

http://bricker.met.p...R09ATMOSRES.pdf

Nice bone thrown to Chris.

[CT Rain]

Nice bone thrown to Chris.

Shabbott love

[Arnold214]

I appreciate the comments. Not a big fan of case studies, but we thought that this paper went well beyond the normal case study and was a really good observational follow-up to the initial paper.

We did give the outflow boundary theory some brief props, but without significant observational evidence of it actually allowing the tornado to go nuts east of the CT valley, we probably would have been hit pretty hard. In my opinion, it was probably a player and we made sure to give it mention as a possibility without stirring the pot too much.

Secondly, another study is currently just underway that will hopefully answer some questions about river valley influences on supercells and tornadogenesis here in the northeast. We are just starting this, and will probably take a good two years to complete, but it looks like an exciting project so far.

[CT Rain]

I appreciate the comments. Not a big fan of case studies, but we thought that this paper went well beyond the normal case study and was a really good observational follow-up to the initial paper.

We did give the outflow boundary theory some brief props, but without significant observational evidence of it actually allowing the tornado to go nuts east of the CT valley, we probably would have been hit pretty hard. In my opinion, it was probably a player and we made sure to give it mention as a possibility without stirring the pot too much.

Secondly, another study is currently just underway that will hopefully answer some questions about river valley influences on supercells and tornadogenesis here in the northeast. We are just starting this, and will probably take a good two years to complete, but it looks like an exciting project so far.

Awesome work, Mike. Great read, well written, and a perfect supplement to the 2010 research.

[radarman]

If anyone is interested in the case study that couldn't access EJSSM, the NWS Taunton page has it up under the top news banner.