Lightning Frequency vs Storm Mode

[Dave Marshall]

Until very recently I lived in the deep South, squarely in lightning country. Having originally come from the Great Lakes, the frequency and intensity of lightning down there was quite impressive.

Over the years down there, I did notice an interesting trend. Linear thunderstorms, airmass type storms in particular tended to be prolific lightning producers, while supercells occurring in the same region, even just a few days apart, weren't nearly as electrically active. That wasn't a hard and fast rule, as I saw some wicked light shows from supercells, but those storms were definitely outnumbered by the supercells with just 'average' lightning production.

I know that much of the science behind lightning is still vague, but does any one know of a particular reason this is the case? I know that instability plays one of the largest roles in overall lightning production, and I don't recall a whole lot of supercell events happening down there with instability tickling 3,500j/kg, while airmass thunderstorms under those conditions are nearly a weekly occurrence in the summer. I also thought I read somewhere that lapse rates play a role, as ice formation within the storm is necessary.

Anybody able to fill in some details for me?

 

[Terry Tyler]

Dave, leading research has said that ice crystals in the upper-level of storms; instability magnitute and quality of moisture has a hand in the lightning production of storms. More often than not, the midsouth has an abundance of these conditions due to our close proximity to the GOMEX. When you are looking at your cold season set-ups with low tops and weak instability. It is not uncommon to have tornadic storms with almost no lightning. As you said, the science behind lightning is very vague. I do not have a degree or certification in weather so I couldnt tell you for sure, only what I have read. What I can say is it depends on the day and the conditions in play. Storms down south tend to have alot more lightning than the northern counterparts, but they too have an abundance of lightning as well. Basically, It is all dependant on the conditions in the atmosphere. Personally, I believe that the quality of the moisture and the tops of the storm make the most difference in which ones make lightning and which ones do not.

Professionals on this forum, such as rdale may be able to furthur explain this to you. I noticed that your question had not been responded to, and since I am from the south I figured I would try to answer the best I could.

 

[Adam Adkins]

I'm not too sure moisture has that much to do with it. Based on this map, there is an increased area of lightning frequency in Colorado - which is a high plains desert. And that area is on the palmer divide which is almost always the least moist zone of the state (apart from the mountains).
I really think it comes down to CAPE. The higher the thunderstorm instability, the stronger the updrafts. With the more significant cooling of the air at the top of the updraft produces a glaciation charge differential in the anvil. This is directly related to lightning frequency. And that explains the increased lightning in CO, higher elevation results in faster cooling temps with height. There is also wind shear which can help mix around the moisture and the air. But I guess moisture also has to do with it now that I think about it. More moisture usually results in more instability, and lightning frequency is directly related with the mass of the water and ice in the storm.