Why do clouds disappear during a solar eclipse?

A partial solar eclipse with some dark cloud in the sky

It might sound odd, but in certain weather situations clouds can disappear from the skies during a solar eclipse. The disappearance of clouds is just one of the several eerie impacts such as darkening skies and absence of bird song that are likely to be observed during this year’s total solar eclipse.

The event will take place on 8 April, with several minutes of totality experienced in a narrow corridor across Mexico, the US and Canada.

An eerie chill

As the Moon passes in front of the Sun, casting a shadow on Earth and turning day to dusk, the most noticeable meteorological affect to many will be the drop in temperature.

In blocking out our main source of energy we may notice the drop in warmth on our skins immediately, but it can take up to 20 minutes for the air temperature to reach its lowest point.

This is because of the way our air is actually warmed. It is not warmed directly by the Sun, but instead by the Sun’s warmth radiating back out of the ground, and this takes a little longer.

The amount the air temperature drops will vary depending on the overriding weather conditions, but most places under the line of totality can expect a drop of at least a couple of degrees.

[PSI Editor’s note: isn’t it odd how climate ‘experts’  who peddle the stupid greenhouse gas theory, can’t even admit that this is another empirical proof that the sun, not carbon dioxide, is responsible for warming our planet?]

During the eclipse across Europe in August 1999, Szczawnica in southern Poland observed a temperature fall of as much as 11 Celsius (20F).

It is that change in temperature that also drives other weather changes.

Calm in the darkness

The wind can fall lighter and change in direction slightly. As the air cools it becomes slightly denser (heavier) and so has greater friction with the ground.

This causes it to slow slightly and take an anti-clockwise shift, so a south-westerly wind would become slightly more southerly.

These changes were highlighted in a 1901 study by American meteorologist Henry Helm Clayton, following an eclipse in May 1900.

Drops in wind strength and temperature can also have an impact on energy demand and renewable energy generation, but the effects of an eclipse are now factored into modern weather computer models to help energy companies in managing these.

Disappearing clouds

Perhaps the most magical weather change during an eclipse is the sight of clouds evaporating.

Now, this will not happen in all situations, and not necessarily with every cloud in the sky.

The type of cloud present ahead of the eclipse is crucial. Cumulus clouds, those fluffy fair weather clouds, are the ones likely to be affected the most.

They form on and are supported by pockets of air rising from the ground and condensing into clouds.

A specific temperature is required for that process to begin and continue. That will vary depending on the atmospheric conditions of the day, but should the temperature fall below that crucial value, as it may do during the process of the eclipse, the skies are liable to clear.

Once the eclipse is over, and if temperatures return to where they were before, the clouds should start to reappear. The breeze will pick up too, and nature should wake up from its brief pause.

Source: www.bbc.co.uk

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Comments (11)

  • Avatar

    Herb Roser

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    So if your on the ocean during a solar eclipse the temperature will not drop at all because the water temperature does not change (water absorbs IR).
    Since water does not absorb visible light either, maybe the clouds disappear since they are not scattering the visible light coming from the sun.
    It is amazing what excuses fools will concoct in order to avoid admitting they don’t know. If the sun is heating the Earth and then the Earth heating the atmosphere how does the atmosphere get above freezing while there is still snow on the ground?

    Reply

  • Avatar

    Jerry Krause

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    Hi Herb,

    “So if you’re on the ocean during a solar eclipse the temperature will not drop at all because the water temperature does not change (water absorbs IR).” My exclamation is all radiation incident upon an ocean surface is either reflected from the surface or transmitted through the surface, where it maybe absorbed by impurities in the water. And because water has the highest ‘specific heat of any matter, any localized heating is undetectable.

    Have a good day

    Reply

  • Avatar

    Jerry Krause

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    Hi Herb,

    “So if your on the ocean during a solar eclipse the temperature will not drop at all because the water temperature does not change (water absorbs IR).” My explanation is any radiation incident upon an ocean surface is either reflected from. its surface or transmitted through its surface to be absorbed by impurities in it. Because water has the highest specific heat of all matter; any localized absorption of energy is undetectable.

    Have a good day

    Reply

  • Avatar

    Wisenox

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    It’s a shadow.

    Reply

  • Avatar

    Jerry Krause

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    Hi PSI Readers,

    “Perhaps the most magical weather change during an eclipse is the sight of clouds evaporating. Now, this will not happen in all situations, and not necessarily with every cloud in the sky. The type of cloud present ahead of the eclipse is crucial. Cumulus clouds, those fluffy fair weather clouds, are the ones likely to be affected the most.”

    While I don’t know (have observed) what clouds can be observed to be most affected during a solar eclipse, I know they cannot be cumulus clouds because because these clouds are described as being dense clouds. Cumulus clouds are a factor because they are “fair weather clouds”. I would speculate that very ‘thin’ cirrus clouds near the top of the tropopause during fair weather would likely be the clouds most affected.

    Have a good day

    Reply

    • Avatar

      Jerry Krause

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      Hi PSI Readers,

      Need to correct what I just wrote. Just went out for a walk and observed what I would term thin cumulus clouds. However, they’ were rapidly evaporating (disappearing).

      Have a good day

      Reply

  • Avatar

    JaKo

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    That is great news indeed!
    Wow, so there will be no clouds during this eclipse, maybe any eclipse; the same as during the night… Oh, wait a moment, don’t these night clouds get “support heat” from the man-made OCO at the night time? Now, wouldn’t that be fair for the eclipses? — No green-building for them, even for the few minutes they last. Despicable, we should complain to the IPCC to issue a Manndate to fix that oversight (I suggest a ground-hockey stick).
    Cheers, JaKo
    BTW, cumulus clouds have many forms in the troposphere and beyond: from the (stage one) lovely puffy creatures all the way to the monster anvil-shape cumulonimbus incus with lightning, hail and all, the latter would surely laugh at any eclipse.

    Reply

  • Avatar

    Jerry Krause

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    Hi JaKo,

    Hadn’t read your comment before my last. But clearly a “cumulonimbus incus with lightning, hail” is not a fair weather cumulus cloud.. Are you trying to confuse readers?

    Have a good day

    Reply

    • Avatar

      JaKo

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      Hi Jerry,
      Confuse? By stating the fair truth??
      You see, if you’ve ever driven across the prairies in, say August, you may notice a fair weather in the morning with these fluffy cumuli, turning a bit too big for that fluffy depiction by noon and by mid afternoon these become quite extensive and vertically unchallenged, and by late afternoon you could get it all: lightning, rain and hail, and, if you’re “really lucky,” and a couple liddle fronts happen to glide by, you may get a tornado or two by the evening. All made by the same phenomenon (pssst, do not mention any “thermals,” there may be some evil genius vortices standing by to blast us out of our element…)
      So, unless we’re talking Texas PM, nothing of that sort would happen during our liddle April eclipse and we may see some disappearing fluffies!
      Cheer-up, JaKo

      Reply

      • Avatar

        Matt Holl

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        You’re confused, yuh moron. (nod nod, wink wink) 🙂

        Reply

  • Avatar

    MC

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    BBC writer? Haha haha haha haha haha haha haha haha haha duck off herb haha haha haha haha duck off even more Jerry crouse,haha haha haha haha. All 3 of them are self idolising idiots. Rate met. 138.

    Reply

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