Cloud Formations

It was drizzling when I got up this morning, but I just peered out the window from office and the sky looks gorgeous! So many different types of clouds in the sky, which is somethig rather unusual. Lemme see...

There's Cirrus Clouds which are the thin and wispy ones. The most common form of high-level clouds are thin and often wispy cirrus clouds. Typically found at heights greater than 20,000 feet (6,000 meters), cirrus clouds are composed of ice crystals that originate from the freezing of supercooled water droplets. Cirrus generally occur in fair weather and point in the direction of air movement at their elevation.

I see puffy cotton balls floating in the sky, otherwise known as Fair Weather Cumulus Clouds. Fair weather cumulus have the appearance of floating cotton and have a lifetime of 5-40 minutes. Known for their flat bases and distinct outlines, fair weather cumulus exhibit only slight vertical growth, with the cloud tops designating the limit of the rising air. Given suitable conditions, however, harmless fair weather cumulus can later develop into towering cumulonimbus clouds associated with powerful thunderstorms. Fair weather cumulus are fueled by buoyant bubbles of air, or thermals, that rise upward from the earth's surface. As they rise, the water vapor within cools and condenses forming cloud droplets. Young fair weather cumulus have sharply defined edges and bases while the edges of older clouds appear more ragged, an artifact of cloud erosion. Evaporation along the cloud edges cools the surrounding air, making it heavier and producing sinking motion (or subsidence) outside the cloud.

Also, there are some Stratus Clouds. The word stratus comes from the Latin word that means "to spread out." Stratus clouds are horizontal, layered clouds that stretch out across the sky like a blanket. Sometimes a layer of warm, moist air passes over a layer of cool air. Stratus clouds often form at the boundary where these layers meet. Where two such layers of air meet, the warm air is cooled. If the warm air is cooled below its dew point, the excess water vapor condenses to form a blanket - like layer of stratus clouds. If the layers of air are very large, the stratus clouds may extend for many kilometers across the sky.

These are the three main categories of clouds. One more type is the Cumulonimbus Clouds, which reach high into the atmosphere. Cumulonimbus clouds (Cb) are much larger and more vertically developed than the fair weather cumulus. They can exist as individual towers or form a line of towers called a squall line. Fueled by vigorous convective updrafts (sometimes in excess 50 knots), the tops of cumulonimbus clouds can easily reach 39,000 feet (12,000 meters) or higher. Lower levels of cumulonimbus clouds consist mostly of water droplets while at higher elevations, where temperatures are well below 0 degrees Celsius, ice crystals dominate. Under favorable atmospheric conditions, harmless fair weather cumulus clouds can quickly develop into large cumulonimbus clouds associated with powerful thunderstorms known as supercells.

Source: http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/cumulonimbus.rxml?hret=/guides/mtr/cld/cldtyp/home.rxml