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Megaflashes: Long-Distance / Long-Lasting Lightning Discharges

EnolaGaia

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With the proliferation of weather-monitoring satellite technologies researchers are better able to identify and quantify massive horizontal lightning discharges that can span areas hundreds of miles across (and spawn air-to-ground lightning strikes).

Such region-spanning discharges may help explain Fortean incidents in which a ground strike occurs without there being an active thunderstorm in sight.
How Big Can Lightning Get?

On Oct. 22, 2017, storm clouds gathering above the central United States released a flash of lightning so huge that it illuminated the skies above Texas, Oklahoma and Kansas. Horizontally spanning more than 310 miles (500 kilometers) across these three states, the jolt was so unprecedented that a group of researchers wrote a study about it, describing it as a "megaflash": It was one of the longest lightning flashes ever recorded.

Typically, regular lightning flashes measure between just 0.6 miles and 20 miles (1 and 20 km) in length. But as increasingly sophisticated mapping techniques have revealed, some truly colossal bolts are crackling above our heads. These recent discoveries raise an interesting question: How big can lightning actually get? And should we be worried about these atmospheric heavyweights? ...


... Vertically, the extent of a flash is limited by the height of a storm cloud, or the distance from the ground to its pinnacle — which is about 12 miles (20 km) at its highest. But horizontally, an extensive cloud system provides much more room to play with.

Back in 1956, a meteorologist named Myron Ligda demonstrated this when he used radar to detect the longest lightning flash anyone had ever recorded at that point: a bolt that spanned 60 miles (100 km). ...

Then in 2007, researchers broke the record by identifying a flash over the state of Oklahoma that measured 200 miles (321 km) long. The recent study by MacGorman and his colleagues knocked that number out of the park. The light emitted by this flash was so strong that it illuminated a ground area of 26,000 square miles (67,845 square kilometers), the researchers calculated. But even that flash has now been surpassed: Another recent study in the journal JGR Atmospheres described a flash spanning 418 miles (673 km). ...

"Such events can often lead to ground strikes far away from the main lightning activity in the convective core," ... "Someone on the ground could think the storm has passed, but be caught by surprise by one of these spatially extensive discharges seemingly from nowhere." ...
There's much more explanation given in:

FULL STORY: https://www.livescience.com/how-big-can-lightning-get.html
 
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It seems new records for verified megaflash distance and duration have been identified.
700-km Brazil 'megaflash' sets lightning record: UN

The UN's weather agency announced Thursday the longest lightning bolt on record -- a single flash in Brazil on October 31, 2018 that cut the sky across more than 700 kilometres.

That is equivalent to the distance between Boston and Washington DC in the United States, or between London and Basel, Switzerland, the World Meteorological Organization said in a statement.

WMO's committee of experts on weather and climate extremes also reported a new world record for the duration of a lightning flash, with a single flash that developed continuously over northern Argentina on March 4, 2019 lasting for a full 16.73 seconds.

The new "megaflash" records, which were verified with new satellite lightning imagery technology, were more than double the previous known record-holders, WMO said.

The previous record for the longest detected distance for a single lightning flash was 321 kilometres (199 miles), measured on June 20, 2007 in the US state of Oklahoma, WMO said.

The previous duration record was 7.74 seconds, measured on August 30, 2012 in southern France, it said.

FULL STORY: https://news.yahoo.com/700-km-brazil-megaflash-sets-lightning-record-un-174859429.html

See Also:
https://www.accuweather.com/en/seve...s-to-break-a-world-record-wmo-confirms/766082

https://public.wmo.int/en/media/press-release/wmo-certifies-megaflash-lightning-extremes
 
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The UN's weather agency announced Thursday the longest lightning bolt on record -- a single flash in Brazil on October 31, 2018 that cut the sky across more than 700 kilometres.

New records for megaflash distance and duration have been announced by the World Meteorological Organization, based on 2020 data.
Longest lightning bolt record: 477 miles over 3 states

A bolt of lightning that stretched nearly 500 miles across three U.S, states is the new world record holder for longest flash.

The single flash extended 477.2 miles (768 kilometers) across Texas, Louisiana and Mississippi in April 2020, the World Meteorological Organization said Monday. That beat the old record set in 2018 in Brazil of 440.6 miles (709 kilometers).

Also in 2020, a single lightning flash over Uruguay and northern Argentina lasted 17.1 seconds, nipping the old time record of 16.7 seconds. ...
FULL STORY: https://apnews.com/article/science-0b0910d7e69bc4f821c3e9730d4929d8
 
Not a single discharge, mind you, but several times I've had continuous thunder over a period of hours. That's as in, "It just doesn't stop". It's quite beautiful, in its way.
 
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