I've been noticing that large (for the northeast US!) lightning storms seem to lose their lightning as they move over downtown Boston. Example gif below (from today, August 19 2021, ~5 am - 11 am local time; taken from lightningmaps.org):

Closeup of Connecticut and Massachusetts, showing dozens or hundreds of strikes over central Connecticut decreasing to about a dozen total as it passes over Boston

This storm isn't as extreme a case as I've more typically seen, where the cities ~10 miles southwest of Boston will get dozens or hundreds of lightning strikes; the Boston College area (about 5 miles from downtown, in a greener/ less paved area) will get dozens; and the downtown will get only a few. But I haven't looked at the data to see how typical that observation really is.

I also looked at this storm's lightning map around New York City and Philadelphia. Those cities appeared to get more lightning than Boston, but then the areas past them seemed to get almost none at all, almost as if they were in the cities' "shadows" (Aug 18, 10 pm - Aug 19, 9 am):

Closeup of New Jersey and surrounding regions, showing hundreds of lightning strikes over eastern Pennsylvania that decrease rapidly in number after passing over NYC and Philadelphia. The lightning increases again, at a lower density, over Connecticut.

The lightning then seems to pick up again over Connecticut on its way to Boston.

So: is it true that thunderstorms "lose" their lightning as they pass over cities? If so, why?

Map showing where Boston, NYC, and Philadelphia are:

A map showing where Boston, NYC, and Philadelphia are.

  • 2
    $\begingroup$ Ocean shipping lanes have the opposite effect. futurism.com/… wired.com/story/… $\endgroup$ Aug 22, 2021 at 5:11
  • $\begingroup$ Cities have skyscrspers which rend to "attract" lightning. Skyscrspers are built with lightning rods to manage this risk. $\endgroup$ Aug 24, 2021 at 1:20


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