Type of Supercell: tornado strength/type etc.

[Jason Harris]

Jerry's question makes me wonder if there are any compiled statistics on the frequency, intensity, and variety of tornadoes associated with LP, Classic, HP, and "hybrid" respectively. How does the likelier event of a rain-wrapped tornado with an HP effect the tornado's shape (width etc.), duration (shorter?), and strength? Have long-tracked tornadoes generally been from classic Supercells? What are the exceptions and why? Does the amount of cycling vary by supercell type as well? Do you make decisions based on the likelihood of a storm getting its act back together with a new circulation after occlusion depending on the supercell type? Have you noticed that certain supercell types tend to more often have satellite tornados than others? What about gustanadoes, land-spouts, straight-line winds etc? Cyclonic vs. anti-cyclonic? Maybe most of these things have no relation whatsoever, but if they do, it would be great to know. I'm interested to hear about both the gathered data and anecdotal experiences.

 

[Chris Lott]

I honestly have no idea on this subject, but I would think HP sups would produce more short lived tornadoes, due to the rain cooled air cutting off the inflow to the storm, but I'm sure I'm completely wrong on this subject.

 

[Laura Duchesne]

Very interesting question, Jason. Well I would tend to think that HP supercells would produce more brief tornadoes (a la May 26th last year. Chris you pretty much nailed it with the HP supercell tornadoes. In fact... most rain wrapped tornadoes will be brief, although there are some exceptions (a la Kearney EF-2). I saw a nice rain wrapped one back in 2006 with only lasted a minute or two but it sure looked like a nice decent cone! Although it did become rain wrapped, the supercell itself was considered a classic.

Correct me if I am wrong here, but I think LP supercells would produce less tornadoes compared to other supercells. I am not quite sure exactly why, but I think it has to do with the structure, lacking RFD etc. Perhaps someone else with more experience than I could elaborate?

IMO the classic supercells are the best for the most frequent, most photogenic tornadoes because their structure usually allows for better inflow, rear flank downdrafts, etc.

Gustnadoes I personally don't really consider tornadoes, because they are caused by outflow winds at the surface. The only times I have witnessed these were on outflow dominant storms. They can also occur in the RFD from supercells.

As for tornado shape.... I am not sure. I have seen a wedge-like but weak tornado near Odessa, TX in 2007. So size does not really indicate how strong the tornado is.... I think classics would tend to have a better chance of producing wider tornadoes. You really got me thinking and asking myself questions now!

 

[Brandon Ivey]

I always like to look at it from a perspective of balance of inflow/outflow in the storm.

LP's are inflow dominate storms. They do produce some tornadoes when enough moisture is available, but tend to produce large hail as their main severe weather threat.

Classic supercells are well balanced in relation to the inflow/outflow of the storms. This leads to a lot of the cyclic storms and long tracked, violent tornadoes. I think the tornadoes can sustain themselves longer becuase the inflow is not overpowering the RFD and the RFD is not too strong that it cuts off the inflow right away. The FFD also plays a role in this balace by containing just enough rain cooled air for the updraft, but not too much.

HP's are messy and contain rain-wrapped tornadoes (most of the time). Many tornadoes in HP storms are short lived due to stronger RFD and heavy precip easily cutting off inflow and occluding the circulation.

Being very brief there, but mainly look at the balance of inflow vs. outflow. If both are strong and well balanced then that is when you will most likely see that large wedge that stays on the ground for miles. Classic supercells are a storm chasers dream! I also like the LP's due to thier photogenic nature, but classic's can be tornado machines at times! Even moreso when they parallel a surface boundary.

 

[Shane Adams]

One thing to remember on this subject, all supercells are constantly in a state of flux, and are morphing from one type to another. It's easy to get stuck on "this is a so-and-so type supercell", but all sups are fluid and are always changing. The best example of a true, steady-state supercell type would be an LP, but even those are subject to minute-to-minute changes.

More than supercell type, I would say tornado type depends on other things in the local environment, such as the LLJ, LCL, and any boundary that might be lying around. One thing to look at as a possible "tell-tale" sign of what kind of tornado you could expect is the LL meso/tornado cyclone. Many times the parent rotation's characteristics will shed some light on what the tornado may be like. Large, rapid, consistent wall clouds/tornado cyclones often-times produce large, strong tornadoes. On the other hand, higher-based storms with little or no wall cloud (but rapid cloud base rotation) are likely to produce skinnier, more "landspoutish" looking tornadoes.

None of this is set in stone, just some observations I've noted over the years.

 

[Dean Baron]

Correct me if I'm wrong but I'm pretty sure the Parkersburg storm this year was an HP. I've seen reports from a couple different people who were chasing it and they never actually saw the monster wedge, the only way they knew that there was a tornado was the damage they came across. This question would be interesting to do some research on. June 11th of this year featured nothing but HP monsters and most of the tornadoes that were reported in IA/MN that day were relatively weak and short lived but then the storm I was chasing put down an EF2 near Spencer. To me it doesnt seem like it really matters what type of supercell it is, there is some other deciding force behind it...

 

[Jason Harris]

The Parkersburg supercell was one of the storms I had in mind wondering about here.
http://www.stormtrack.org/forum/showthread.php?p=213061#post213061
I was lucky enough to be with a group who was following that storm, though we only got to see the second Fairbank to Hazleton area tornado that followed up. Bob Hartig's video there captures our experience.
http://www.stormtrack.org/forum/showthread.php?t=16588&highlight=parkersburg&page=6


We got pelted from some falling mud and what looked like aluminum while driving when the Parkersburg tornado was active--blasting past some imminent hail to get in a better position. Kurt Hulst did get video of the Parkersburg wedge
http://www.stormtrack.org/forum/showthread.php?t=16588&highlight=parkersburg&page=5

 

[Matt Gingery]

The supercell thunderstorm has one side of the wall cloud is rain-free, while the other is neighbored by dense shafts of rain. Simply because the downdraft never impedes the updraft. Usually the more dominant cells are capable of producing the long track type tornadoes. Those that have no impedence on inflow or outflow. Nearly a perfect balanced scenario. In alot of cases the UA will push the cells out ahead of the surface boundary and like in one of the earlier posts, it has almost everything to do with having a balanced scenario. Now, I don't know if the Parkersburg Iowa Cell was part of the HP mess that hit Kearney etc. I was chasing that day, and The Parkersburg cell seemed to hang out ahead of the initial HP mess, unless I am wrong, may have to check the data base. I would say that it was a perfect balanced scenario. I cannot imagine a HP rain wrapped tornado being long track, that depends on what you would call long track. Personally, precip is a tornadoes worst enemy. I would say the Parkersburg core was H.P. but the rear flank would have most certainly been a localized tight rain free area. Just a thought. Lots of good questions in your post Jason.

 

[Bobby Prentice]

Jerry's question makes me wonder if there are any compiled statistics on the frequency, intensity, and variety of tornadoes associated with LP, Classic, HP, and "hybrid" respectively.

None that I can recall. But in general, classic supercells are the most prolific producers of strong and violent tornadoes. Significant tornadoes with true LP supercells are very rare.

How does the likelier event of a rain-wrapped tornado with an HP effect the tornado's shape (width etc.), duration (shorter?), and strength?

There's lots of speculation, but I don't know of any research studies on these topics.

Don't get too caught up in supercell type. Supercells fill a spectrum and don't fit into nice neat boxes. Also, supercells continually evolve and its rather common for LP supercells to transition to Classic and then HP (i.e., they get messier over time).

Have long-tracked tornadoes generally been from classic Supercells?

Yes. That's a safe assumption. Most long track tornado families are produced by classic supercells.

What are the exceptions and why?

HP supercells can produce strong and violent tornadoes, too. But they generally aren't long track family events. Speculation is that there is too much interference from precip and other factors.

Does the amount of cycling vary by supercell type as well?

Yes. See above.

Do you make decisions based on the likelihood of a storm getting its act back together with a new circulation after occlusion depending on the supercell type?

Yes. Problem is tornadic supercells rarely "get their act back together" (e.g., after they are undercut by cold outflow, new cell's can't form due to increasing convective inhibition, etc.).

Have you noticed that certain supercell types tend to more often have satellite tornados than others?

Satellite tornadoes are rare. I've seen more with classic supercells than other types, but that might be because significant tornadoes produced by LP supercells are very rare, while HP supercell tornadoes are often rain-wrapped and not easily observable..

What about gustanadoes, land-spouts, straight-line winds etc? Cyclonic vs. anti-cyclonic?

What about them?

Maybe most of these things have no relation whatsoever, but if they do, it would be great to know.

What relationships are you asking about?