2017-10-22 "Megaflash" Lightning is Longest on Record

[Randy Zipser]

Wow! I'm having a hard time "getting my head" around this one, but here is the story (dated July 31, 2025) from NBC News:
A shocking record: Lightning bolt stretched 515 miles, crossed three states

 

[Dan Robinson]

The news articles about these tend to misunderstand what these record-length flashes are. These are basically overachieving "anvil crawler" flashes entirely within the stratiform regions of long squall lines. I wrote an article on the first of these (I'll need to update it with this one when I get a chance):

MYTH: World-record "megaflashes" mean that lightning can strike hundreds of miles away from a thunderstorm

 

[Randy Zipser]

The news articles about these tend to misunderstand what these record-length flashes are. These are basically overachieving "anvil crawler" flashes entirely within the stratiform regions of long squall lines. I wrote an article on the first of these (I'll need to update it with this one when I get a chance):

MYTH: World-record "megaflashes" mean that lightning can strike hundreds of miles away from a thunderstorm

Thanks, Dan, for your article. I had never heard of this phenomenon until now! RZ

 

[Randy Zipser]

Thanks, Dan, for your article. I had never heard of this phenomenon until now! RZ

Dan, BTW, here in Florida we see a lot of what we call locally "heat lightning," especially on summer nights. Flashes occur silently (no thunder) overhead seemingly with no storms anywhere nearby, sometimes even with few or no cumulus clouds even around. I suspect these are also due to long-ranging propagation of ordinary light at the altitude of typical thunderstorm anvils which could be 20 or more miles away, which is refracted horizontally under certain atmospheric conditions (such as differing air-mass density away from the near-storm environment). Have you seen this phenomenon and do you have an explanation for it?

 

[Dan Robinson]

Dan, BTW, here in Florida we see a lot of what we call locally "heat lightning," especially on summer nights. Flashes occur silently (no thunder) overhead seemingly with no storms anywhere nearby, sometimes even with few or no cumulus clouds even around. I suspect these are also due to long-ranging propagation of ordinary light at the altitude of typical thunderstorm anvils which could be 20 or more miles away, which is refracted horizontally under certain atmospheric conditions (such as differing air-mass density away from the near-storm environment). Have you seen this phenomenon and do you have an explanation for it?

Randy,

'Heat lightning' refers to horizon-level flashes from distant storms during clear, calm nights, but as it's a colloquialism it might have regional variants in meaning. At least here in the Midwest, I can see flashes from storms 200+ miles away with nothing but cloudless skies overhead. Back in WV we'd have 'heat lightning' from storms much closer as the horizon was usually much higher.

 

[Boris Konon]

The news articles about these tend to misunderstand what these record-length flashes are. These are basically overachieving "anvil crawler" flashes entirely within the stratiform regions of long squall lines. I wrote an article on the first of these (I'll need to update it with this one when I get a chance):

MYTH: World-record "megaflashes" mean that lightning can strike hundreds of miles away from a thunderstorm

In the original article on megaflashes:
"Megaflashes are not altogether uncommon, but they typically only occur in parts of the world where specific geographical and atmospheric conditions can produce the most severe thunderstorms, Cerveny said. In the Great Plains and across the Midwest, for instance, warm and humid air from the Gulf of Mexico collides with drier, colder air from the north, creating strong atmospheric instability."

The same tired trope about the "clash of air masses." We see the same thing when it comes to tornadoes. This is something that the MSM never seems to get or shed. And even w/ the statement itself here, it is wrong, as in "creating strong atmospheric instability," You don't need a "clash of air masses" for that!

 

[Boris Konon]

When it comes to how far a CG can strike from the parent updraft, when a thick downwind anvil from a cell is present, I have seen strikes occur as far as 90 mi from the updraft core. It's not that the bolt travels 90 mi originating from the updraft, a +CG occurs vertically from the anvil itself overhead.

 

[Randy Zipser]

The same tired trope about the "clash of air masses."

Remember, Boris, that Cerveny's remarks are intended for a public audience, not higher-educated, formally-trained meteorologists like us. So, Cerveny's statements are intentionally of the unsophisticated variety that a non-meteorological person will understand and accept without much additional consideration. In addition, Cerveny is a regular contributor in several informational programs, such as Weird Earth, for example, on The Weather Channel. So, I wouldn't be "too hard" on Cerveny or others whose comments are intended to appeal to (or even to educate on a very basic level) the lay public. My 2 cents...

 

[William Monfredo]

...statements are intentionally of the unsophisticated variety that a non-meteorological person will understand and accept without much additional consideration...

I'm glad that you have patience for this sort of thing, but the media does not get a pass for misleading people w/ meteorological misinformation.

 

[Boris Konon]

Remember, Boris, that Cerveny's remarks are intended for a public audience, not higher-educated, formally-trained meteorologists like us. So, Cerveny's statements are intentionally of the unsophisticated variety that a non-meteorological person will understand and accept without much additional consideration. In addition, Cerveny is a regular contributor in several informational programs, such as Weird Earth, for example, on The Weather Channel. So, I wouldn't be "too hard" on Cerveny or others whose comments are intended to appeal to (or even to educate on a very basic level) the lay public. My 2 cents...

Understood, but we shouldn't promulgate a myth or falsehood for sake of simplicity for the general public. Educate up, not dumb down I always say. Things can be explained in a way that the general public understands, and I have found many appreciate that. For instance, the reason why the Plains are so conducive for svr wx and tornadoes has little to w/ the clash of air masses, everything to do w/ the area's geography! On a large-scale, it is unlike anywhere else in the world, and that's why it is the absolute max for tornadoes. Most of the general public I bet do not know this, but would be able to understand the concepts behind this (large, relatively shallow warm gulf next to flat, sloping Plains that are just E of a high N-S mountain chain).

It's like how ball lightning keeps coming up in the media, where there is no concrete proof that is exists, at least in the form of how it documented going back 100s of years. Tell *that* the general public and the level of uncertainty, instead of shallow speculation or conjecture loaded w/ tropes.

On a New England wx Facebook page I am part of, most are not meteorologists, lots of wx enthusiasts and those that have at least a passive interest in wx. I post often, esp. about false or exaggerated claims about wx, and will explain what is what, and so many appreciate it b/c it is very hard these days to know what is what w/ the information overload and so many sources to get information. They also like their skepticism they have about certain claims and stories are valid often. They say, "that doesn't seem right" or "is it really that bad?" but they not sure what the real deal or explanation actually is. This is where meteorologists can step in and explain to them the who, whats, wheres, and whys, and do it w/o hype or flowery language.