Sometimes, in the mountains or hills, these clouds appear to be fog. Weather prediction: Fair, but gloomy. Cumulonimbus clouds grow on hot days when warm, wet air rises very high into the sky. From far away, they look like huge mountains or towers. Weather prediction: Look out for rain, hail, and tornadoes! Stratocumulus clouds are patchy gray or white clouds that often have a dark honeycomb-like appearance.
Weather prediction: Fair weather for now, but a storm might be on its way. Contrails are made by high-flying jet airplanes. They are still clouds, though, because they are made of water droplets condensed from the water vapor in the exhaust of the jet engines. Weather prediction: Contrails can provide information about the layers of moisture in the sky. Mammatus clouds are actually altocumulus, cirrus, cumulonimbus, or other types of clouds that have these pouch-like shapes hanging out of the bottom.
The pouches are created when cold air within the cloud sinks down toward the Earth. Weather prediction: Severe weather might be on its way!
Orographic clouds get their shape from mountains or hills that force the air to move over or around them. Cirrocumulus clouds are usually associated with fair weather, as precipitation from them never reaches the ground, although their appearance can often be before stormy weather, meaning you should make the most of the sun while you still can. The thin, layered cirrostratus cloud is composed of ice crystals. Cirrostratus form a veil or thin sheet of cloud that covers all or part of the sky.
Altocumulus clouds normally appear white or grey with shading. They are usually seen in settled weather. They are usually composed of droplets, but may also contain ice crystals. Precipitation is rare, but if it does fall, it never reaches the ground, re-evaporating before it reaches the surface. Altostratus evolves as a thin layer from a gradually thickening veil of cirrostratus.
They appear as almost featureless sheets of cloud and are usually grey or blue. Their appearance precedes a warm front and usually indicates a change in the weather is close. As the front passes, the altostratus deepens and bulks out to become nimbostratus.
These dark, grey, featureless clouds are usually accompanied by moderate rain or snow, lasting several hours. Nimbostratus clouds are dark, grey, featureless layers of cloud. They are thick enough to block out the sun and often produce persistent rain or snow that will last until the front has passed.
If there is hail, thunder or lightning present as well as rain, it is a cumulonimbus cloud rather than nimbostratus. Stratocumulus cloud consists of large, rounded, clumpy masses of cloud that form groups, lines or waves. They can be seen in all weather conditions from dry settled to wetter weather.
Why do clouds form at different heights in the atmosphere? The characteristics of clouds are dictated by the elements available, including the amount of water vapor, the temperatures at that height, the wind, and the interplay of other air masses.
How is fog formed? There are many different types of fog, but fog is mostly formed when southerly winds bring warm, moist air into a region, possibly ending a cold outbreak. As the warm, moist air flows over much colder soil or snow, dense fog often forms. Warm, moist air is cooled from below as it flows over a colder surface. If the air is near saturation, moisture will condense out of the cooled air and form fog.
With light winds, the fog near the ground can become thick and reduce visibilities to zero. You need warm air! They are mostly made of drops of water. Wayfinder navigators use clouds to work out where the wind is coming from or if it changes direction so they can trim their sails accordingly. Like smoke from a haystack, cloud roads follow the wind. A cloud road indicates the wind is coming from the horizon.
If the road is straight, the wind is steady — but if you see the road curve, it means that the wind direction will change. The way the road curves will tell you the new direction. Instead, you have to observe changes over time. The Connected article Sun, wind or rain? Clouds and the weather observes cloud types and how they help predict the weather.
0コメント