Weathercatch: Cloudy with a chance of picnics

Now that it’s March, two types of clouds are appearing more often and they’re not the kind that will rain on your parade.

Cirrus and cumulus are known as fair weather clouds. Their displays overhead mean the weather is just fine, thank you, and it’s a good day to clean garden debris, take a hike or plan a picnic. Often strewn across cobalt-blue skies, these friendly white clouds produce no rain or snow and typically portend pleasant conditions. Both are more common during spring and summer months.

Beyond that, cumulus and cirrus couldn’t be more different. One forms close to earth and resembles cotton balls; the other is thin and wispy and created miles higher in the atmosphere. They’re not even made of the same thing.

As we move deeper into spring, we’ll be seeing these two wonder clouds more often. That said, let’s bring them down to earth to take a closer look:

Cumulus: These are the fluffy, whimsical clouds that children like to draw. Their name is derived from the Latin term, cumulo, meaning heap or pile. They float at 6,000 feet or lower in the atmosphere and are made mostly of water droplets. They’re also loaded with air bubbles, which gives them their characteristic cotton-candy like appearance. They are formed through the process of convection when the sun heats the ground and causes a column of warm air to flow upward. Warm air holds more water vapor molecules than cool air. As the heated column of air rises, it eventually cools, causing the water vapor to condense and form a cumulus cloud. Mostly, cumulus clouds add tranquil character to bright, sunny skies. Occasionally, however, they don’t stay quiet. Strong air currents can cause them to bubble upward to produce dense and billowing mushroom-like cumulonimbus clouds associated with severe thunderstorms, hailstorms and even tornadoes.

Cirrus: The highest of all clouds, these are delicate swirls or fine, narrow streamers. Their name is derived from the Latin term cirro, meaning curl. They occur anywhere from 16,500 to 40,000 feet – significantly higher than cumulus clouds. They are composed of minute ice crystals that get twirled about in high-altitude winds to produce feathery streaks of clouds. They appear to drift slowly because they’re so far away. But in reality, they can zip along at speeds of up to 200 mph. Most often, their presence means pleasant weather conditions for that day. But if you notice them thickening into dense sheets, it may be a sign that a front is approaching that will bring some unsettled weather. Although silky-white during daytime, cirrus clouds can take on a spectacular array of colors during sunrise and sunset.

There’s a good chance you’ll see one or both of these cloud types over the next few days as the region dries and temperatures edge upward. Expect mostly sunny and partly sunny skies this weekend, with highs in the low 50s.

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Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Weiford can be reached by email at ldweiford@gmail.com