As the eclipse begins, some clouds blocking the view may disappear. A recent study found that after 15 percent of the sun is covered, cumulus clouds, the small cotton balls common on a sunny day, can disappear. Even if you’re outside the path of totality, watch what happens to the clouds.
If the sky is full of these tiny clouds at the start of Monday’s eclipse, it will be fun to count them and watch them slowly disappear, said Victor Trees, a study author and a Ph. D. candidate at Delft University of Technology and Royal Netherlands Meteorological Institute. But if the sky is overcast, he said, “we don’t expect the eclipse to let this cloud deck disappear, and it could actually spoil the view of the eclipse for a local observer.”
The type of clouds in Dr.’s study. Trees, the cumulus, tend to bubble because the sun’s heat on the Earth’s surface forces low-level air to rise, similar to the way water collects as it boils in a pot. As warm air rises, it cools to a point where condensation can occur. During the eclipse, the temperature near the ground will cool, limiting the rising air, much like a person turning down the heat on a pot of boiling water to bring it to a boil.
Although some cumulus clouds may be present on Monday, the dominant cloud cover over parts of the South and Northeast will likely come from several storm systems that are creating the types of clouds that are less affected by temperature changes created by the eclipse.
For those lucky enough to be in an area where the clouds disappear, wait and watch as they begin to pop back into view after totality.
