Search results
Results from the WOW.Com Content Network
Altocumulus (from Latin altus 'high' and cumulus 'heaped') [1] is a middle-altitude cloud genus that belongs mainly to the stratocumuliform physical category, characterized by globular masses or rolls in layers or patches – the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus. [2]
When these high clouds progressively invade the sky and the barometric pressure begins to fall, precipitation associated with the disturbance is likely about 6 to 12 hours away. A thickening and lowering of cirrocumulus into middle-étage altostratus or altocumulus is a good sign that the warm front or low front has moved closer and it may ...
The altocumulus undulatus is a mid-level cloud (about 8,000–20,000 ft or 2,400–6,100 m), usually white or grey with layers or patches containing undulations that resemble "waves" or "ripples" in water.
Mid-level stratocumuliform clouds of the genus altocumulus are not always associated with a weather front but can still bring precipitation, usually in the form of virga which does not reach the ground. Layered forms of altocumulus are generally an indicator of limited convective instability, and are therefore mainly stratocumuliform in structure.
The base of the cloud can form as low as 2,000 metres (6,500 feet), or as high as 6,000 metres (20,000 feet). They are very similar to cumulus congestus clouds, but at a higher level and with the cloud heaps joined at the base. Castellanus clouds are evidence of mid-atmospheric instability and a high mid-altitude lapse rate. [2]
Cumulus humilis clouds usually indicate fair weather. [23] Cumulus mediocris clouds are similar, except that they have some vertical development, which implies that they can grow into cumulus congestus or even cumulonimbus clouds, which can produce heavy rain, lightning, severe winds, hail, and even tornadoes.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Heights of various cloud genera including high-, mid-, and low-level clouds. Altostratus and altocumulus clouds are the two genera of mid-level clouds that usually form between 2,000 and 6,100 m (6,500 and 20,000 ft). [4] [39] These are given the prefix "alto-". These clouds are formed from ice crystals, supercooled water droplets, or liquid ...