<p>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):</p>
<p><a href="https://i.sstatic.net/CVTdE.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/CVTdE.gif" alt="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" /></a></p>
<p>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 <em>really</em> is.</p>
<p>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 <em>past</em> them seemed to get almost none at all, almost as if they were in the cities' &quot;shadows&quot; (Aug 18, 10 pm - Aug 19, 9 am):</p>
<p><a href="https://i.sstatic.net/Di9Xq.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Di9Xq.gif" alt="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." /></a></p>
<p>The lightning then seems to pick up again over Connecticut on its way to Boston.</p>
<p>So: <strong>is it true that thunderstorms &quot;lose&quot; their lightning as they pass over cities? If so, why?</strong></p>
<p>Map showing where Boston, NYC, and Philadelphia are:</p>
<p><a href="https://i.sstatic.net/P7oMs.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/P7oMs.jpg" alt="A map showing where Boston, NYC, and Philadelphia are." /></a></p>

CC BY-SA 4.0
2021-08-22T05:11:39.550Z
Ocean shipping lanes have the opposite effect. https://futurism.com/pollution-from-ships-is-causing-lightning-storms-over-ocean-shipping-lanes https://www.wired.com/story/why-lightning-strikes-twice-as-much-over-shipping-lanes/
Keith McClary
CC BY-SA 4.0
2021-08-24T01:20:16.953Z
Cities have skyscrspers which rend to "attract" lightning. Skyscrspers are built with lightning rods to manage this risk.
Oscar Lanzi
<lightning><thunderstorm><united-states>
Does lightning strike density decrease over cities?
Natavi
# Does lightning strike density decrease over cities?

(Asked by: username_0 on 2021-08-19)

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](https://i.sstatic.net/CVTdE.gif)](https://i.sstatic.net/CVTdE.gif)

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.](https://i.sstatic.net/Di9Xq.gif)](https://i.sstatic.net/Di9Xq.gif)

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.](https://i.sstatic.net/P7oMs.jpg)](https://i.sstatic.net/P7oMs.jpg)

**Tags:** lightning, thunderstorm, united-states

> **Comments:**
> **username_1**: Ocean shipping lanes have the opposite effect. https://futurism.com/pollution-from-ships-is-causing-lightning-storms-over-ocean-shipping-lanes https://www.wired.com/story/why-lightning-strikes-twice-as-much-over-shipping-lanes/  
> **username_2**: Cities have skyscrspers which rend to "attract" lightning. Skyscrspers are built with lightning rods to manage this risk.  

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## 0 answers

