What differentiates cirrocumulus from cirrostratus is the presence of instability at cloud level. Cause: Lifting of a large air mass, followed by condensation combined with wind shear at cloud level. spider's web of contrails that occurred day after day, high above England, as the Luftwaffe and the Royal Air Force engaged

As cirrus uncinus generally indicates the presence of high- Hazard Warning: Severe turbulence in cloud, strong winds, lightning, hail, and even tornadoes at ground level. In this variation, the wind shear gives rise to a more intricate pattern of small waves, which produces the much finer texture of mackerel sky. Are as wide as they are tall.

In dry areas, showers may fall from the cloud base but evaporate before reaching the ground, a phenomenon known as virga. Cause: Lifting of a large air mass, followed by condensation combined with instability. The powerful convective updrafts associated with calvus clouds can produce significant turbulence. Height: 0 to 1000 feet above ground level. Mount Everest, and sometimes reaching 60,000 feet in tropical and subtropical areas. This reverse-direction convection is enhanced by the effects of gravity and by precipitation from the cloud. air temperature drops below freezing, this part of the cloud is composed of ice crystals, which forms a crown of cirrus above Cumulus humilis is the smallest form of cumulus cloud and results from relatively weak convection (humilis means humble in Latin). This creates vertical eddies, or waves, of air between the layers, and if sufficient moisture is present, cloud will form where the wave rises and dissipate where it falls. They are inevitably more common in highly fire-prone areas such as California, the French Riviera, and southeastern Australia. Strong wind They are not large enough to produce precipitation.

A mature cumulonimbus incus is definitely the "King of Clouds", a mighty mountain of moisture often considerably taller than Less common, but equally dramatic, is cirrus radiatus, which forms in long, parallel lines that seem to radiate from a point on the horizon. As with other undulatus forms, these ripples are produced ABN: 88 495 561 455, Copyright 2020 Higgins Storm Chasing ® | All Rights Reserved | Powered by. rises and dissipating it as the air descends on the other side

Congestus seldom forms as a result of convection alone. The principal difference between the two formations is that altocumulus is affected by instability in the surrounding Associated Weather: Can produce moderate to heavy showers. often forming spectacular patterns that may stretch for In this case, lightning strikes If several ground observers have noted castellanus development by the middle of the day, then there is a greater Cirrocumulus, like cirrostratus, occurs when a large area of moist air at a high level of the atmosphere reaches saturation and forms ice crystals. In most cases, however, the turbulence would cause little discomfort to pilots or passengers.

cumulonimbus clouds, but particularly those bearing mammatus formations, as these indicate especially severe turbulence within the cumulonimbus. The wind flows through the area of In this case, the clouds may subsequently develop into cumulus Among the most common are fibratus and nebulosis. Hazard Warning: Clouds may develop into cumulonimbus and trigger further fires through lightning strikes. The base of this medium-sized cloud (mediocris means moderate in Latin) can begin to form from 2,000 feet upward, depending on the surrounding humidity. Cause: Saturation of air mass at upper levels. Cause: Strong convection followed by The exact causes of this pattern have not been firmly cumulonimbus clouds occur, but it is particularly common in areas where thunderstorms are severe, such as tropical and subtropical areas. Its also this ice which leads to cirrus clouds being some of the most known clouds for producing cloud iridescence which is where clouds can produce rainbows from the sun refracting off ice crystals. and about 6,500 feet.

Normally, the lifting of the air mass is a result of an incoming frontal system or wind encountering a large landmass such as a mountain range. As with all cumulus clouds, this is a result of a certain amount of instability at cloud level, which gives rise to further Contrails also have a military and strategic significance in These streaks of cloud have a characteristic flick, like a horse tail. Similar to cirrocumulus, but individual segments are larger and darker. The winds in these levels of the atmosphere can be constantly strong to very strong and its this wind shear that can morph and shape the clouds into different formations. To report a Copyright Violation, please follow Section 17 in the Terms of Use.

This motion is normally a result of wind shear, which occurs when one layer of air slides over another layer moving at a different speed or in a different direction (or both). Often altocumulus and altostratus appear together in a Cirrus may be the result of local thunderstorm activity. They can indicate an approaching warm front, however, they can also be an indication that fair weather will follow. shape and wind may move at different speeds at different In its full magnificence, it is crowned with a huge, wedge-shaped mass of high cloud resembling a blacksmith's anvil (incus is the Latin word for anvil). Cause: Lifting of a large air mass, followed by condensation. When translated to their Latin heritage, the word cirrus can mean lock or tuft of hair, and thats exactly how they can appear in the sky as many photographers refer to cirrus clouds as horse-tail clouds. Stratus is the lowest altitude cloud formation, with As with altostratus, altocumulus normally occurs when a large air mass is lifted to middle levels by a landmass or an incoming frontal system, and condensation occurs over a wide area. The former consists of long, thin filaments, known as striations, that spread out

It is this visible formation that is known as a contrail. by atmospheric waves generated by wind shear. or two after forming and, as a result, is rarely observed. the cumulonimbus cloud reaches the top of the troposphere, Associated Weather: Drizzle or slight rain, or snow in sub-zero temperatures. cloud will produce precipitation.

cloud over a period of time, it may indicate the approach of a frontal system. However, the precipitation associated with the cloud can usually be located by onboard aircraft radar and evasive action taken. Cause: Saturation of a large airmass at high levels, combined with instability at cloud level. It was first described in the late nineteenth century by Baron Kelvin (1824-1907), a Scottish physicist, and Hermann von Helmholtz (1821-94), a German physicist -- hence the name of the cloud. Nimbostratus usually produces precipitation over a wide area, due to instability in the atmosphere. Generally, no significant weather is produced by altocumulus lenticularis, but, occasionally, if there is sufficient moisture in the surrounding atmosphere, these clouds can become thick

hundreds of square miles. Altitude above 6,000 m (Above 20,000 ft).