Mother Nature decided that today is cool clouds day! A speedy eight-hour loop of today's satellite imagery across the eastern U.S. reveals plenty of cool features to drool over, including a vanishing storm and a mysterious swirl over Lake Huron. Let's take a look...

[The image at the top of this post is animated and somewhat large—it may take a moment to load.]


It was a pretty foggy morning across much of the middle East Coast between Charlotte and Baltimore, with visibility reaching zero in many locations. Fog is pretty cool to look at on visible satellite because, unlike most clouds, fog is a uniform, white deck of gloom that often forms around terrain instead of above it. The result is usually a spidery, splotchy deck of low clouds that twists and turns with rivers, lakes, hill, and mountains.

As the sunlight heats the atmosphere and causes the temperature to climb away from the dew point (lowering the humidity), the fog starts to burn off, leaving clear skies in its wake. In areas where the fog burns off early enough and sunlight is able to directly heat the surface, patches of cumulus clouds often develop.

Pennsylvania Thunderstorm

Watch the animated image at the top of this post. See the thunderstorm that comes into view across south-central Pennsylvania around sunrise? It completely dissipates as soon as it hits the cooler, more stable fog bank. It vanishes into a puff of high-level cirrus cloud in just a few frames.

More thunderstorms are forming behind that line as of 400PM EDT, some of which could reach marginal severe levels with hail the size of quarters being the main threat.

Mysterious Swirl Over Lake Huron

Starting around 1700 UTC (200PM EDT) this afternoon, a very interesting feature popped up over Lake Huron (the one that makes up the eastern shore of Michigan). A defined swirl in the clouds followed by an almost eye-like clearing appeared over Kincardine, Ontario and spun southwest back over the lake. The feature is approaching the center of the lake and is becoming obscured by high-level clouds in recent satellite imagery.

The best theory I've come up with regarding this feature's creation is that it's a bookend vortex—a counterclockwise rotation that forms at the northern end of a squall line—created by a line of showers and storms that moved through the region during the morning and early afternoon hours. If any meteorologists have a better theory, chime in down in the comments!

NASA's website is one of the best sites available for GOES East and GOES West satellite imagery. Give it a look every once and a while—odds are, you'll find something interesting when you least expect it.

[all images via NASA]

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