Clouds may disappear during April 8 Total Solar Eclipse, scientists say

Accurate weather forecasts for the April 8 path of totality won’t be available until a few days later, but scientists have confirmed that cumulus clouds over Earth begin to disappear almost immediately when a partial solar eclipse begins.

It’s something eclipse chasers have known for at least 40 years. Still, the Publication of paper inside Communications Nature Earth and Environment lends further credence to the long-observed phenomenon.

However, how the cloud evolution caused by the eclipses works will likely have huge implications for those traveling to parts of 15 US states – as well as Mexico and Canada – to see the final total solar eclipse in consecutive USA by 2044.

Eclipse Cooling

Although the effect of solar eclipses on clouds has been observed for centuries, this is the first time the strength of the ‘eclipse cooling’ effect has been measured.

Science is elementary. Ground warming drives convective clouds. So if the ground cools, they disappear. The disappearance of cumulus clouds during a partial solar eclipse was confirmed by researchers using satellite images taken during three partial solar eclipses in Africa between 2005 and 2016. They calculated the percentage of the sun that was shadowed for each location and time on Earth.

Unofficial data

“From Earth, you can count the clouds and watch them disappear, but that only provides anecdotal evidence.” he said Victor Trees, lead author, at Delft University of Technology in the Netherlands. “So far, most of the solar eclipse consists of a partial eclipse, where there is still plenty of light outside,” he said. “In this partial eclipse, the satellites receive enough reflected sunlight, after correcting for the obscuration, to count clouds reliably.”

The 15% rule.

Cumulus clouds over the earth are very sensitive to solar eclipses and begin to disappear on a large scale when the sun is about 15% eclipsed by the moon. The researchers also simulated the disappearance and reappearance of clouds, revealing that air ascent is affected almost immediately when a partial eclipse begins. However, over the sea, clouds remain unaffected during a solar eclipse because seawater does not cool as quickly.

Amazing Speed

“It’s been known to eclipse hunters for 30 years that convective clouds break up during an eclipse — and it works everywhere,” said meteorologist Jay Anderson, who plans eclipse missions and whose climatological analysis of eclipse tracks in Eclipsophile is avidly read by eclipse chasers. He did not participate in the investigation. “What surprises people is how quickly they can disappear during a total solar eclipse – it can go from 70% cloud cover to 1% in five to 10 minutes.” Small convective clouds only have a lifespan of 10 minutes at most, “so if you cut off the heating, they’re done,” Anderson said.

For eclipse hunters in the northeastern US and Canada looking for a 60%+ chance of cloud cover based on historical weather maps, the “eclipse cooldown” is a reason to ignore the naysayers and get in the path of totality.

Path of Wholeness

While everyone in North America will see the partial phases through solar eclipse glasses, only those within the 115-mile-wide path of the moon’s shadow will enjoy a brief totality. This will last up to 4 minutes and 26 seconds in Mexico and Texas, reduced by about a minute as the path of totality tracks southwest to northeast across the US and Canada.

This path of totality will cross parts of five states in Mexico (Sinaloa, Nayarit, Durango, Coahuila and Chihuahua), 15 US states (Texas, Oklahoma, Arkansas, Missouri, Illinois, Kentucky, Tennessee, Michigan, Indiana, Ohio, Pennsylvania , New York, Vermont, New Hampshire and Maine) and six Canadian provinces (Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia and Newfoundland).

For the latest on all aspects of the April 8th total solar eclipse in North America, check out my main stream for new articles every day.

I wish you clear skies and open eyes.