Look at the Sky

Seriously, look up once in a while. The sky can tell you all about what the weather is doing, or even WILL do, later that day or tomorrow. Here’s some tips!

Clear Blue Sky (No Haze or Clouds)

Is really rare in Louisville, KY. We swelter in a humid continental climate, on a large river. Enjoy this nice picture of a cloudless desert landscape, instead.

A teddy bear cholla patch. And now you have a hint at an upcoming post!

By Ciar (Own work) [Public domain], via Wikimedia Commons

A totally clear sky like this means that there’s so little moisture in the atmosphere that clouds can’t form. It probably won’t rain for a while, since water vapor has to move in before that can happen.


Cirrus Clouds

Indicate that a mass of moist air is moving back in, and rain or snow might be possible soon.

Wispy thin cirrus clouds.

By Ron Clausen – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=61703893

Remember: “Mare’s tails and mackerel scales mean rain in three days.”



City haze on main street, Louisville, KY.

There we go. That’s weather we’re all familiar with.

When it’s hazy, it means that there’s a layer of warmer air trapping air pollution and humidity close to the ground. If this inversion is strong, it will prevent clouds from developing. If clouds manage to punch through it, storms could be strong. If you see haze, it probably won’t rain, but if it does, it will storm.


Fair Weather Cumulus

Fair weather cumulus clouds - fluffy and flattened, as if confined by invisible panes of glass on top and bottom.

By Nicholas A. Tonelli from Pennsylvania, USA (Prairie Walk (2)) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

These clouds in an otherwise clear sky mean that there’s convection going on, and enough water vapor in the air to form clouds. However, the air pressure is too high, or the convection too weak to really build up. If you see these early in the morning, it might rain later, but if they’re about in the afternoon, it’s going to continue to be nice for a while.


Cumulus Congestus

And now the clouds are starting to pile up.

Big, intimidating cumulus congestus clouds, towering above the trees.

CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=101225

If you see these before noon, someone’s in for a soggy evening.


Thunderstorm (Cumulonimbus)

A big thunderstorm cloud with a characteristic flat anvil-like top.

CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=100357

A column of convection so strong that it piles up high enough to splash flat against into layer of hot stable air of the stratosphere is certainly a thunderstorm. Always be aware of clouds like this with flat “anvil” tops: they’re the towering monsters of the sky, multiple times bigger than other cumulus clouds, and capable of producing severe weather like hail, tornadoes, and flooding.

And now you know some of what the sky can tell you about the upcoming weather. Keep an eye out, and it might just come in handy!


Weird and Rare Clouds

Although the following clouds are unusual or rare where we live, they are really cool, and that’s worth something by itself.


Fallstreak Hole

Fallstreak hole in a cloud with ice crystals raining out.

By Pfranson – Taken by Paul Franson in Warr Acres, Oklahoma with a Casio EZ-Z1050 Previously published: http://www.flickr.com/photos/pfranson365/4238892215/, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=27741283

This can happen when clouds made of water vapor are just on the point of freezing into ice crystals. When some of the water vapor freezes and clumps together, it snows out of the cloud layer, leaving a hole in the cloud.


Lenticular Clouds

When air pressure drops abruptly (as when wind flows around mountains), layered, lens-shaped clouds like these can form.

Lenticular clouds looking like a stack of pancakes over a mountain range.

By Alpsdake – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16399555


Roll Clouds

Are clouds that occur when a wave propagates in otherwise still air on the verge of being able to make clouds. The low-pressure pocket travels through the air, made visible as a cloud that seems to slowly roll through the air. Gliders and birds can “surf” the atmospheric wave for long distances. There’s a very reliable roll cloud called the Morning Glory that propagates on the Gulf of Carpentaria in Australia. No pictures, because pictures really don’t do it justice.