They float in the sky above us and block out the Sun. Sometimes, they are in the form of a continuous layer with an undulating surface. Altocumulus clouds are also more commonly observed than cirrocumulus. They signify a change in the weather, and indicate that a cold front is closing in normally resulting in subsequent thunderstorms in spring or summer or a rain front in autumn and winter that will rapidly clear as the cold front with its associated weather sets in. High cloud - cirrus, cirrocumulus, cirrostratus, Middle cloud - altostratus, altocumulus, nimbostratus. Other planets with atmospheres have clouds including Venus, Jupiter, and Saturn. They will often form in patterns appearing as bands of clouds slowly progressing across the sky. High - High level clouds form above 20,000 feet. Altocumulus clouds are a type of mid-level cloud that forms at between 2,000 and 6,000 meters in altitude. The name is derived from unda, the Latin word for a wave. High level clouds usually have the prefix "cirro" or "cirrus" in their name.

Meteorologists study the formation and make up of clouds to understand the weather better. They are grayish-white with one part of the cloud darker than the other. Because it is colder higher up, these clouds are mostly made of ice crystals. They can appear when cold fronts are moving in and brief periods of bad weather can be expected. Given that they can form at heights from 6,000 feet to altitudes as high as 20,000 feet they can be made up of water particles or ice particles at the higher altitudes.

As they are found at relatively high altitudes, they are not affected by thermal updrafts and they are not susceptible to the weather conditions that form the lower level cumulus nimbus clouds, nor do they produce such dramatic results in the form of thunderstorms in spring and summer time or heavy downpours in the autumn or winter. Known as Altocumulus Standing Lenticular (ACSL) or Altocumulus Standing Lenticularis clouds, they are associated with waves in the atmosphere that develop when relatively stable, fast moving air is forced up and over a topographic barrier that is oriented more or less perpendicular to the direction from which the upper-level wind is blowing. Even though clouds float in the air, a single cumulus cloud can weigh hundreds of tons. They are often composed of mostly water droplets. They are often composed of mostly water droplets. It is rare but not impossible to see these clouds when there are higher layers of cirrostratus clouds above. Altocumulus may also be observed on or near the sides of Cumulonimbus. These clouds are very tall and may span many of the cloud levels. Low level clouds usually have the word "stratus" in their name. Vertical - Some clouds are vertical clouds. These are called contrails. The text enclosed in grey-shaded boxes, like this example, comprises Annex I to the Technical Regulations (WMO-No. Fog formed when relatively mild air flows over a relatively cold surface is a. radiation fog. c. a mixture of water droplets and ice crystals. Vertical clouds usually have the word "cumulus" in their name. Should you hold your thumb up raised to the sky, your thumb will be able to obscure an individual altocumulus cloud. When you can see altocumulus clouds you should be aware that a cold front is moving in to replace warmer weather and you can expect bad weather or at least cloudy conditions to arrive within the next 24 to 48 hours.   Â, Altocumulus clouds can be found in the middle-level altitudes that are between 6,000 to 20,000 feet, they can be a much as 1 kilometer in thickness, and they are transitory clouds that will only be seen for a number of hours, rarely for days. Low - Low level clouds form below 6,500 feet. Vertical - Some clouds are vertical clouds. c. upslope fog. Vertical clouds usually have the word "cumulus" in their name.

b. steam fog.
Altocumulus (Ac) - the name derives from the latin words altus = high and cumulus = mass or heap.Altocumulus is a member of the ten fundamental cloud types (or cloud genera). The most common locations to find altocumulus clouds:  Â. Altocumulus clouds are classified as a middle altitude cloud that can be found at heights of between 2,000 to 7,000 meters. Altocumulus floccus clouds are normally formed at about 6,500 feet but can even be formed as high as 13,000 feet. Worldwide; they can be found in any part of the globe. These clouds are found whenever there are high hills or mountains. This Altocumulus often forms while the mother-cloud is still in the Cumulus stage.

How are altocumulus clouds formed? Sometimes they are dark and cover the entire sky.

They can be easily spotted thanks to their clumpy or blotchy appearance and they are normally colored from white to a medium grey color. Some clouds you see in the sky might be from airplanes. Altocumulus and cirrocumulus clouds share many of the same cloud species, but cirrocumulus clouds are higher in altitude, so their cloudlets appear smaller. A slow up lift of the water particles creates clouds that are either white or grey if they are denser. They may be made up of water droplets or ice crystals. Altocumulus clouds are made up of water particles that are sucked up from the ground or the sea and carried to higher levels thanks to gentle up winds.

Introduction and principles of cloud classification, Orographic influence on the windward side, Nitric acid and water polar stratospheric clouds, Noctilucent clouds (polar mesospheric clouds), Classification and symbols of meteors other than clouds, Definitions and descriptions of meteors other than clouds, Observation of meteors other than clouds from the Earth's surface, Observation of hydrometeors other than clouds, Observation of clouds from the earth's surface, Observation of clouds from mountain stations, Code specifications and coding procedures, Coding instructions of clouds in the codes C, Issues for observation of clouds from aircraft, Descriptions of clouds as observed from aircraft, Appendix 1 - Etymology of latin names of clouds, Appendix 2 - Historical bibliography of cloud classification, Appendix 3 - History of cloud nomenclature, Appendix 4 - Lists of tables, figures and acronyms, Foreword to the 1987 edition of volume II, Supplementary features and accessory clouds, Main differences between Altocumulus and similar clouds of other genera, An increase in size or a thickening of at least some elements of a patch, sheet or layer of Cirrocumulus (Ac cirrocumulomutatus ), Subdivision of a layer of Stratocumulus (Ac stratocumulomutatus), Transformation of Nimbostratus (Ac nimbostratomutatus), Spreading of the tops of Cumulus when they reach a middle level stable layer (, Cease at the stable layer, resulting in patches of Altocumulus spreading out from the top of the Cumulus, Temporarily stop at the stable layer and then resume their growth in places or throughout, resulting in Altocumulus on the sides of the Cumulus. It is a middle-level cloud, thus they usually form between 2 to 7 kilometers (6,500 to 22,000 ft). These clouds are very tall and may span many of the cloud levels.


Altocumulus is a type of cloud which belongs to the group of clouds found at medium height, between 8,000 and 18,000 feet (around 2,500 to 5,500 meters). Sometimes clouds are white and puffy. All clouds with ‘undulatus’ in their name have wave-like features to them. Altocumulus clouds are found at a mid level between 6,000 and 20,000 feet and they appear to look like beaded or bands of cloud or they are round like cotton wool balls that almost appear to  be stuck to  the deep blue sky above. Middle - Middle level clouds form between 6,500 and 20,000 feet high. Low level clouds usually have the word "stratus" in their name.  Â. Altocumulus clouds are very common and can be found anywhere where there are hills or mountains in their vicinity. Low - Low level clouds form below 6,500 feet. High level cirrus clouds may travel at speeds up to 100 mph. d. Any of the above is correct. Altocumulus clouds usually form in groups and are about 1 km thick. Medium level clouds usually have the word "alto" in their name. advection fog.